Bulletin


WAX. HIST. SURVEY

(^ tura.1 IIisto]:*3r Suii^vey

The Crayfishes and Shrimps
(Decapoda) of Illinois

The Ubrary of ttit

NOV 41985

Unive(»/,, u.
It UrteiM-CiMinoaj^q

Lawrence M. Page

STATE OF ILLINOIS

DEPARTMENT OF ENERGY AND NATURAL RESOURCES

NATURAL HISTORY SURVEY DIVISION

CHAMPAIGN. ILLINOIS

VOLUME 33, ARTICLE 4

SEPTEMBER 1985



SIAIt OK II-UNOIS DtPARIMtMOF KNtROV ASH NA R RAL RtSOl R(.LS

BOARD OK NA ri'RAl. RKSOIRCKS AND CONStRV A HON

Don Ktciiison. Ph.D.. Chairman; H..S. (.iTnwsKV. Ph.D.. Snyrlajy. (:heitn\tt\: Robert U Me7< aij. Ph.D.. fiiohfisy: Wai TF.lt E.

Hanson. M.S.. t.u^inreriti^: Lorin I. Nrvi.iN*.. Jr.. Ph.D.. Fotrstry: I,. 1.. .SrjOvi. Ph.D.. f>o/<»)fy. riiPoix»Rr- 1.. Broun. PhD . Hrprr-

srulinii tfir i*re<,i<ifnl of ihf I'mTfrsily oj llUuon: .\ni\ joHS (;. (il ^on, Ph D , Hrpmrnliini thr Frr^idrnt of \oulltrTJi tllmnis I 'nn>rrMr\

NATURAL HISTORY SURVEY DIVISION, Champaign, Illinois

SC:iKN riKIC: AND rE<:HNK;AL S lAFK

Paul (;. Risser. Ph.D.. CJnrf

Amcf., K. Adam.s. Secretary lo thr Chirf

SECTION OF AQUATIC BIOLOGY
C.c)KI>^N. RoBKRi VV. Pn-D.. l(/NHf/( Rioloni^l nnd llrad

Bi'CK, D- HoMKR. PiiD., .lijwilK liinlttiii\l

I,ARiM(iR». R. Wfiiion. PhD. Aquain Riiilnii,i\(

Sharks. RrcHARU K. Ph.D.. Aqunlii Rioloi>i\t

Hf.hkndfjn. Robf.rt a,, Ph.D.. AssiHiatr Atftiatu Rntlo^isi

pHH iPf. David P.. Ph.D.. Asfiotiate Aqualu fiiolni^ist

Rfinboi D, Kfti'Rah a,. PhD . Awnnate Aqualu Binl<>si\t

Ross. Phji iPCF., Pii.D . Aystxtatf Aqunlu /iioi(>iii\l

Bavi.fv. Pftkr B., Ph.D.. Ay-^nlanl Aqualu liuilof'isl

Hfnfbrv. Mtchaki. S., Ph.D.. Awistanl Aqunlu Builoi^i\l

Hicks. Randai.i,. Ph.D.. As'.islani Aquniu Hinloiiist

Horns, Wh.i.iam H.. Ph.D.. AsM\ianl Aqualu Bioloiiist

I.l'BiNSKl, Kennfiii S., Ph.D.. Ay\islant Aqualu Binlo^isl

Starnf.s, Wavnf. PhD-. A\si\laul Aqualu Biolotiist

.Storc:k. IfdW,. Vu.U.. Awnlanl Aquafu Biolofiist

Wn.KY, MicHAKr J.. Ph.D.. A--\i\tan( Aqualu Butlaf^ist

San[)BFR<.er. Jf-Ns-Diftfr. M.S.. A\'-i\lanl Supporlur Si ifnli.\l

Waitf. Jana I... M.S.. Assislnnl Supportn-r Si trnii.\l

W'arrfn. (.arv 1. , B.S.. AsM.Uanl Supptntivf SnrtUnl
Ai'sTFN. Doi'f.l.AN, M.S.. }u>u(n I'Tiilrwinnal SiifnliU

Hoof,, M u:ha F-I. M.S.. Juuun l>Ti>frss,„nal St irnli.yl

HiftFRT. Bfveri.f.y. Junior l*ii)fe\Mi)iial Surnlist

KwAK. Thomas |.. M.S., Junmr Pmfrwinunl \iifttlt\t

Pfrrv, l.ANCF-. M.S.. Juniur I'rnfr.ynitnal Si it'Ulisl

SoBASKl. .StfPHES v.. B.S., luni'ir I'rulrwional Siirntist

.Sons. tii<;FNK. Junior PrnfrsMotml S< irnlist

Iazik. Pamf-1-A p.. M.S.. Junuir P^ofewional Siifnti\l

Dovvi,iN(.. David, M.S., Tri imnal Assistant

twiN(., Kathar^n I... B.S,, Tnhniinl Awistanl
KoPHFiMAN, Jfffrf\. M.S.. Tfi liniinl Awistanl
I.voN, Dai.f. M.S.. Tnhnunl Assislnnt

Nf.wman. Barky t.. B.S., Tr-ihnual Assislnnl

.ScHMiTTi.FH. Crak. D . M.S., Trifiuuat Assi\lant

Wai.nfr. Ri'iH. Tr< hnnal A\si\lnnt

{^I.Ai'S.SF.N. Ji'I.iF,. B.S., Junior Trihnual .-tssnlnnt

C^RAWFORD, LoI'Ann, B.S,. Junior Tri linual A.wnlanl

(;ros.sf.tt. Lorrik, MS., Junior Tfihnuat .-ixMslitnt

DfQi'fnnf, Barbara, yuM/or Tnhnifal Assistant

Das, Daviu, E.S.. Junior Tn hniial A\\i.\lnnt

K1FID.S, Robert, H.S.. Juuioj Tnlinnnl A<<si\tanl

CiRUBAlHiH, Jack, M.S., Junu>r Trihnual Awistant
MAtiNEl.lA. Stfve. B.S,. Junior Trihnual Awntanl
Mai.mf.R, Sl'San. B.S.. Junior Trihnual Awislanl

Mavfr. (jiRl.STiNF, B.S-, Junior Trt hnual AsM\tanl

McDoWF.l.l.. Brian D, M.^.X.. Junior Trt hnual Assistant

Mcl.CCKrF, AiAN D,, B.S, /i/n/ur Trt hint nl Assistant

Mit.l.FR. Sli/.ANNF. M.. M.S.. Junior Trthnunt Assistant

WiKF. I.VNN, M.S., Junior Tri hnii at .Assistant

SECTION OF BOTANY AND PLANT PATHOLOGY
(iRUNWAi.u, Ci.Ai'N. I'h.D., Botanist ami Hratt

(iRANF.. J. [.ELAND. Ph.D,. M\i oloiilSl

HiMFJ.lcK. K. B.. Ph.D., I'lanI I'alholoiiist

Neei.y. Dan. Ph.D.. Plant I'nlholoi^ist

.SciiOENEWF.iss, D, v., Ph.D.. l*liint I'alholngi.st

Robertson. KENNnn R . Pn D , Botanist

KNDRE.VS, Anton (i., Ph.D., Assoi tntr Botanist

IvFRsoN, I.oris R., Ph.D.. AsMstanI Botanist

Sfr(.fni. |a.mf:s K... Assoanlr Suppintwr Surnlist
Nfiaon. Bfttv. Assistant Supportivr Surntist
McKnk.hi. Bh I N., M.S.. Junior ProfrssKfnal Si irntist

Bl'RtoN. Phhip, M.S.. Trihnual Assistant

Harrison. Robert .*\., Trihnual .-tssisiant

Hi'ANc 1.1-Shar. Ph.D., Tn hnual Assistant

Karnf.s, Jean K,. M.S.. Tn hnual Assiytanl

MoRAN. RoBBiN (:.. M.S.. Hrsrari h As.Kistant

Noi.TE, David, B.S.. Hrsranh A.s.ti.Uani

SECTION OF ECONOMIC ENTOMOLOGY
Ri EsiNK. W'h I lAM (... Ph.D., Assoi intr t.ntoinohiiiisl and llrnil

.\itifbn. Jami.s K , Ph.D., hntomolufiist

.\KMBHtiM, Kdward J.. Pii.D., h.nlomotofiist

Ko(.AN. MARt:os. Ph.D.. hnliniuilonist

kt'Ht.MAN, DoNAio K.. Pii.I>.. hnlomoloiiist. h.xtrnsion

Maduox. Josei'H v.. Ph.D.. l:ntotnoh}nnt
Randei.i.. Rosr.oE. Ph.D.. UntmnototiiU. hMrnsmn
B()ti>E\iAN, John K,. M.S., Assminlr hnlonioh^isl
Kasiman. Catherine K.. PhD., .issm intr Kniomotonisl
Kfi.soi. Alt.AN S.. Ph.D.. .4s\iHiittr hlntinnoloiiisl

Irwin. Michafi. 1-... Ph.D.. Assimntr h.ntinnohmist

Levinf, ti.i. Ph.D.. AssiMiatr hnlomologisl
Stefffv. Kevin. Ph.D., .-tsso<iatr t.ntonutlngLst, t.xtm\ti»n

Bhic.us. Stiphen P-, M.S.. Assistnnt Sprtialnl. hxlrnston
Fischer, Daniel. Pii.D.. Assistant I'ralrssuinal StimtiU
Jeffords. Michael. Ph.D.. Assistant Entumutoi^tst
kiLiioN. Ki(;enf K.. B,S.. Assistant hntomohnii.sl. hxtrnsutn
I.AMV. William O.. Ph.D.. Assistant l*rufr\sionat Si irnltU

On.stad. David. Ph.D.. .-tssisiant Profrwumai Si irntist

Mil I FR. t-RFUERic D.. Ph.D.. .issistant Entomoiuf^ist. f.xtrnston

Wei, I.kstlr, Pii.D . Assistant Prnfrwumal Srimttst

Wein/ilri , Richard A,, Pw.li., .•isststant hntomolof^tst, f.xteniirtn

/avaifta, l.iis, Ph.D.. Assistant Frofrsnonal \timtttt

Heim, Charles. C;.. M.S., AssiMiatr Supportn-r Sfirnlist

koGAN. Jenny, M.S., Associalr Supportn-r St irntist

WiusoN. Jean Ci.. B.A., .4sswiatr Supportn-r Stirnttst

.\i bif. JoAnn, Assistant Suppitrtur S<irnti%t

Brfwfr, l^i.i.EN, M.S.. A.ssistant Supportwr Stirntist

(Jit. izi'-SlAN. M.S.. Assistant Supporlnf Sctrntist

C.lsE. (lHARrE.<>, B.S., Axsist. h\t. Sprc, Cornpulrr Applitalntns
Ka.mpmfier, Gail. M.S.. Assistant Supparliif Siirrtltst

l.EpAR. CfERAl D. Assistant Supfmrtn-r Surnlist
McC.iFFFN. MiiTON K,. Jr.. ,\I.S., .4ssistant Supportn-r Stimtisl

HaYER. Karen. .M.S.. Assistant Suppifrtwr Si irntist

Roberts. Stephen J.. B.S., .issislant Supportn-r Scirntist

.Swoeford. David. Ph.D., Assistant Suppojtn-r Siirnlisl

Wai.sh, i.Al'RA. M-S., .-tssisiant Suppinln'r S* imtisl

Da/ey. Doyi e. Junior Profrssumat Stirnlisl

Post, SrsAN. Junior Suppurln'r Stirntisl

(Carpenter. Sherla I.., \..\., Tnhnical Assistant

i'.jssY. I.At'RiE, B.S., Trihnual .issistant

PeteR-s. Brenda M.. Trihnual Assistant

Sherman, Renee. B.S., Trihnual A ssisiani

WiisMANN, Janet I... B.S.. Trihnual Assistant

WiTiiROW. Jane. Trt hnual Assistant

Morris. Marilyn. M.S.. yumor Trihnual A.s.sisiant

Mc(;iiRE. .Michael. M.S.. Junior Trrhnual Axststani

CtRlDER. DntolliCii. Tran.si-ribinfi Srtrrtary, l:\lrnMtttl

Lrdman, Diane. (.Irrk-Typist III

1 RAiB, Joan. (Irrk-T\pist III

S/KonxiNsKl. .\\.\c.f,(.lrrk-Typisl II

BaI'CHMAn. I'homas \.. (iraduatr Hrsranh As.sislanl

.\rif, Syed Moha.mmad, M.S.. (iraduatr Hrsrarch A\st\tanl

Day. tRic. M.S., (iraduatr Hrsrarch .Issisiant

SciiRoEDER. .\i.AN, M.S.. (iraduair Hrsranh .^vw.w«n/

Smith, I.ane. M.S.. (iraduatr Hrsrarfh .-txiislant

KiELDiNc, Dennis J., (iraduatr Trathin^ Assistant

SECTION OF FAUNISTIC SURVEYS AND INSECT
IDENTIFICATION

LaBergf. Wali A( e t.. Ph D,. Insri-t Taxonomisl and Hrad
Brigham. Warren l\, Ph.D . Insrft Taxonomist
Pa(.f. Iamrencf M.. Ph D . Fish Taxonomisl
Webb. Donald W,. Ph.D . Insnl Taxonomisl
Bric.ham, Allison R., Pii.D . .issonatr Piofrssional Stirnti.st

Godfrey, (>eor(.f I... Pil D.. .4\si>tiatr Insrtt Taxonomisl
I'nzicker. John D , Ph.D.. .isAiu lalr In.snt Taxonomisl
Von;riiN. David J.. Ph.D.. Assi.stant Insnt Taxotutmist
rREWoRf.i. C^oLlN (;.. B.S.. As\4uialr SuppttrtuT Sitrnlist

Bi'TCHER. Matthew K. M.S., A\Mslant Supportnr Sarnlifi

Gardner. Genf. M.S.. .issi.stanl Supporln-r Stirntut
HoEMANN. lovcE, Ph.D.. Assistant Supportit^ Siirrtltst

McfiiFFEN. Katiirvn. M.S.. Assistant Supporln^ Sumlisi
PFRAIT. Si'ZANNF J., .issistant Supp<trtii-r Si irntisl

•SoLEiKi, Mar\ Kay. M.S.. A.-i.M.slant Supportiif Surntisl

SiiowAY. LlA.NE B,. M.S.. Assistant Supportn'r Sfirnltsl

Sweeney. Bernice P.. A\sisianl Suppoiiit-r Snmfnt
Kaft. John B.. M.S , .iisistanl Suppintiir Surntisl
I'lMMONs. Randam ('•.. B.S., .iMt.stant Supportu-r Surun':
I'lA/FK, Kric K . B.S,. .4s\islant Suppoilixv Scirnii^f

Wfi/fi. Mark J., M S., Assistant Supporlu-r Stim ^f

Biii.FR. R\ndai I,,. B.S., Junutr Profrssionol Stirn:i\l

BrcH)Ks. Khovlas M . B.S.. Junior Suppotlitf Surnlist
Hoi 1, .\i El A .\ . B.S,. Junior \ii/>/M»rlnr Sarntist
Kasprowu/. jE\NiNf M., B.S.. Junuir Suppo^tnr Stirntisi

Kefnf, Dennis. B.S.. funun Supportnr Surntnn
Mai mboR(., Pmti I.., MS., Srnior Trt hnual .i&sislani

Bkowir. Joan 1... B.S.. Tn hnual Assistant

HtMH)N. Steven. ,\I.S.. Trihnual Assistant

Kffvin, Khomas M.. M-S.. Trthnuat .i\si\tant

KiRTN, .\nn, B.S. Trihnual .issistant

MiiF.s, Chari.ene. Trihnual Assistant

PosMiA, SiE^F. Trt hnual .issistant

Sw ANSON. C^iiARLE.s. S.. B.S,, Tri hnuat Assistant \

U.S LSSN 0073—1918



Nra.tii.ra.1 History Sixrvey

The Crayfishes and Shrimp
(Decapoda) of Illinois

Lawrence M. Page

STATE OF ILLINOIS

DEPARTMENT OF ENERGY AND NATURAL RESOURCES

NATURAL HISTORY SURVEY DIVISION

CHAMPAIGN, ILLINOIS

VOLUME 33, ARTICLE 4

SEPTEMBER 1985



Frontispiece: Orconectes illinoiensis form I male from Gibbons Creek. Herod, Pope
County. Illinois. 4 March 1973.

i



^nis' tepo^i/ i&' dedicated to/

MRS. BERNICE SWEENEY
o*v tke^ occasion' ol k&i/ leiUement/ and uv

konon/ ot ne^ 22 uewi& at se^dce^ toy the/

Section/ ot'^aunisUo SiMueus' and/ 'insect/

'ddenliiication/ ol tAc/ ^(jtinois/ '^yialwiai

^~}(AstjOAij/ SiAAMeu/. '~^teA/ numetous' ketplut

cantuAutions' to/ this/ and oth&i/ studies'

OAe/ sinceAeiu/ ofipneciaied.

Ill





CONTENTS
INTRODUCTION 335

Historical Studies of Illinois Decapods 335

Present Survey Methods 336

Extralimital Species and Studies 336

GEOLOGICAL HISTORY OF ILLINOIS AND ZOOGEOGRAPHY OF
NATIVE ILLINOIS DECAPODS 339

NATURAL HISTORY 343

Crayfish Life Cycle 343

Freshwater Shrimp Life Cycle 345

KEYS TO ILLINOIS SPECIES 345

Key to Decapods of Illinois 348

Key to Illinois Crayfishes, Based on Form I Males 353

SYSTEMATIC ACCOUNTS 356

Family Palaemonidae—Freshwater Shrimps 356

Genus Macrobrachium Bate 356

M. ohione (Smith) 356

Genus Palaemonetes Heller 358

P. kadiakensis Rathbun 359

Family Cambaridae—Crayfishes 362

Genus Cambarellus Ortmann 363

C. shufeldtii (Faxon) 363

C. puer Hobbs 366

Genus Procambarus Ortmann 369

P. gracilis (Bundy) 370

P. acutus (Girard) 376

P. viaeviridis (Faxon) 378

P. clarkii (Girard) 381

Genus Orconectes Cope 386

O. illinoietisis Brown 386

O. immunis (Hagen) 388

O. indianensis (Hay) 394

O. kentuckietisis Rhoades 396

O. lancifer (Hagen) 400

O. placidus (Hagen) 404

O. propinquus (Girard) 406

O. rusticus (Girard) 412

O. slannardi Page 415

O. virilis (Hagen) 4 1

7

Genus Fallicambarus Hobbs 422

F. jodiens (Cottle) 422

Genus Cambarus Erichson 426

C. tenebrosus Hay 428

C. rusliciformis Rhoades 432

C. diogenes Girard 434

C. robustus Girard 439



CONSERVATION 440

ACKNOWLEDGMENTS 440

LITERATURE CITED 441

INDEX 447

Page, Lawrence M. 1985. The Crayfishes and Shrimps (Decapoda) of Ilhnois. Illinois

Natural History Survey Bulletin, Vol. 33, Art. 4. p. 335-448.



The Crayfishes and Shrimps (Decapoda) of Illinois

Lawrence M. Page

Crayfishes and shrimps (Decapoda)

are conspicuous components of the

aquatic environments of Ilhnois. Al-

though only 23 species are known to

inhabit the state (Table 1), they are

among our largest aquatic invertebrates

and often are present in large popu-
lations.

HISTORICAL STUDIES OF
ILLINOIS DECAPODS

Most of the historical information

available on crayfishes and shrimps of^

Illinois is that published by Forbes

(1876), Rietz (1912), and Brown (1955).

The "List of Illinois Crustacea" was,

as Forbes (1876) noted, "a first contri-

bution to the knowledge of our Crusta-

cea," and contained the "results of a

single season's work." Included in the

list were Macrobrachiurn ohione, Pal-

aemo7ietes kadiakensis (as P. exiUpes),

Procambarus acutus (including Cam-
barus stygiiis), P. gracilis, Orconectes

immunis, O. propinquus, O. rusticus

(as O. placidus), O. virilis (including

O. wisconsinensis), and Cambarus
diogenes (as C. obesus). Hagen, in his

earlier (1870) monograph on North
American crayfishes, had noted the

occurrence in Illinois of all of the above

crayfishes except P. gracilis. Hagen
erroneously also recorded for Illinois

P. troglodytes, an Atlantic Coast

species.

A bachelor's thesis submitted to the

University of Illinois in 1912 (Rietz

1912) and entitled Ecological Relations

of the Crawfishes of Illinois added to the

list of Illinois species O. indianensis, C.

robustus (also listed for Illinois by

Faxon 1885), C. tenebrosus (as C. bar-

toni brevis), and Fallicambarus fodiens

This papti is published by aiilhoriiy of the

.Stale of Illinois and is a contribution of the Ser-

lion of Kaunistif .Surveys and Insect Identification

of the Illinois Natural History Survey. Dr. Lav\-

rence M. Pa^e is a Zoologist in the- .Sec tion.

(as C. argillicola, also listed for Illinois

by Faxon 1890).

A doctoral dissertation submitted to

the University of Illinois in 1955, The

Biology of the Crayfishes of Central

and Southeastern Illinois (Brown 1955),

was based on extensive collecting (at 4 10

stations) in the Sangamon, Wabash, and

Table 1.—Classification of the crayfishes

and shrimps of Illinois, primarily following

Holthuis (1952) and Hobbs (1974b).

Order Decapoda
Family Palaeinonidae

Genus Macrobrachiurn

1. M. ohione (Smith)

Genus Palaemonetes

2. P. kadiakensis Rathbun
Family Cambaridae

Subfamily Cambarellinae

Genus Canibarellus

Subgenus Dirigicambarus

3. C. shufeldlii (Faxon)

Subgenus Pandicambarus
4. C. puer Hobbs

Subfamily Cambarinae
Genus Procambarus
Subgenus Girardietla

5. P. gracilis (Bundy)

Subgenus Ortmannicus
6. P. acutus (Girard)

7. P. viaeinridis (Faxon)

Subgenus Scapulicambarus

8. P. clarkii (Girard)

Genus Orconectes

9. O. illinoiensis Brown
10. O. tmniunis (Hagen)

11. O. indianensis (Hay)

12. O. kentuckiensis Rhoades
13. O. lancifer (Hagen)
14. O. placidus (Hagen)

15. O. propinquus (Girard)

16. O. rusticus (Girard)

17. O. stannardi Page
18. O virilis (Hagen)

Genus Fallicambarus

Subgenus Creaserinus

19. F. fodiens (Cottle)

Genus Cambarus
Subgenus Erebicambarus

20. (.'. tenebrosus Hay
21. C rusticijormis Rhoades

Subgenus Lacunicambarus
22. (.'. diogenes Giraid

•Subgenus Puncticamhnrus
23. (',. robuslus Girard

335



336 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

Ohio river systems. To the growing list

of lUinois species, including Cambar-

ellus shujeldtii and O. lancijer reported

in the interim by Faxon (1914), Brown
added P. clarkii, O. kentuckiensis, and
O. illinoiensis (described by Brown in

1956).

Statewide collections made for the

present survey have added Cambarellus

puer, P. viaeviridis, O. placidus, O.

sta?}nardi, and Cambarus rusticiformis

to the list of Illinois species. The list

of Illinois shrimps and crayfishes now
stands at 23 species.

METHODS
Collecting for the present survey of

Illinois decapods spanned a decade

(March 1972 to September 1982). Col-

lections were made at 1,294 localities

(Fig. 1) in all counties of the state (Fig.

2), but were most heavily concentrated

in southern Illinois, where the largest

diversities of habitats and species occur.

All species of aquatic Malacostraca

(Isopoda, Amphipoda, Decapoda)
present at each site were collected. A
plethora of taxonomic problems among
the isopods and amphipods prevent

their inclusion in this report. Lewis
& Bowman (1981) and Lewis (1982) re-

cently have published distributional

studies on the subterranean isopods of

Illinois.

A dot on Figure 1 indicates that one
or more malacostracans were collected

at that locality. Stations sampled at

which no species were found are not

shown on the map. Although the ab-

sence of malacostracans at a site can be

informative, it may indicate only that

insufficient time was spent in searching.

Old records (pre- 1972) are included on
the species distribution maps when they

document significant changes in distri-

bution (e.g., for Mac robrachiuin
ohione). A lew recently (1984) dis-

covered localities are plotted for O.

rusticus and O. stannardi.

Because ecological analyses were
attempted for each species, all indi-

viduals encountered usually were pre-

served; if large numbers were encoun-

tered, only the early portion of the

sample was preserved, and subsequently

collected individuals were returned

to the water.

Specimens usually were collected by

dipnetting, minnow seining, or by

digging them from their burrows.

Malacostraca require cover, and the

most successful method of collecting

was to place a dip net downstream from,

or (in standing water) next to, accumu-
lations of stones, brush, living vegeta-

tion, etc., and to kick through the

material, thereby dislodging specimens

into the dip net. The most successful

method of collecting burrowers was to

dig into the burrow down to the water

table, splash the water, wait for the

curious crayfish to investigate the dis-

turbance, and grab it. This worked well

in the relatively shallow burrows of

C. diogenes but less well in the deepjer

burrows of P. gracilis. P. viaei'iridis,

and F. fodiens.

Specimens were placed in 10-percent

formalin if large, in 70-percent ethyl

alcohol if small enough to go into a

3-dram \ial. In the laboratory, speci-

mens were washed in water, identified,

counted, sexed, and placed in 70-

percent ethyl alcohol for permanent
storage in the Illinois Natural History

Survey collection. Records were kept

on the presence of form I males and of

females carrying eggs or young.

Measurements of crayfishes are given

in millimeters of carapace length (CL).

Length-frequency distributions are

presented for those species for which
no published growth or longevity data

are available and of which large col-

lections were made in Illinois. Keys,

diagnoses, and descriptions are based

on Illinois populations only. Taxa are

arranged phylogenetically. except
within Orcoiifi tes where species arc

arranged alphabeticalh because of our

present lack of understanding of inter-

specific relationships.

EXTRALIMITAL SPECIES AND
STUDIES

Several spec ies of crav fishes not found



August 1985 Crayfishes and Shrimps of Illinois 337

Fig. 1.— Localities in Illinois where aquatic Malacostraca were collected between March
1972 and September 1982.



338 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

in Illinois live in eastern Missouri and
western Kentucky in streams draining

directly into the Mississippi and Ohio
rivers, and they eventually may be

found, presumably as waifs, in Illinois.

In Missouri, these are Orconectes har-

risoni, O. hylas, O. luteus, O. medius,

O. nais, O. peruncus, P. punctimanus,

O. quadruncus, and Cambarus hubbsi,

and in Kentucky, O. bisectus and O.

tricuspis. It is more likely, however,

that additions to the Illinois fauna will

result from human introductions,

deliberate or otherwise, and could

originate from anywhere.

Regional publications on freshwater

decapods of North America are avail-

able for Alabama (Bouchard 1976),

STEPHENSON WINNEBAGO BOONE McHENRt

Fig. 2—Coun-
ties of Illinois.



August 1985 Crayfishes and Shrimps of Illinois 339

Arkansas (Bouchard & Robison 1980),

California (Riegel 1959), Colorado

(Unger 1978), Florida (Hobbs 1942),

Georgia (Hobbs 1981), Indiana (Hay

1896; Eberly 1955), Iowa (Phillips 1980),

Kansas (Williams & Leonard 1952),

Kentucky (Rhoades 1944a), Louisiana

(Penn 1952, 1956, 1959; Penn & Marlow

1959), Maryland (Meredith &: Schwartz

I960), Michigan (Pearse 1910; Creaser

1931), Nebraska (Engle 1926), New
Jersey (Fowler 1912; Francois 1959),

New York (Crocker 1957), Ohio (Turner

1926; Rhoades 1944b), Oklahoma
(Creaser & Ortenburger 1933; Reimer

1969), Ontario (Crocker & Barr 1968),

Pennsylvania (Ortmann 1906), Texas

(Penn &: Hobbs 1958), West Virginia-

(Newcombe 1929), Wisconsin (Creaser

1932), the Cumberland Plateau and
Cumberland Mountains (Bouchard

1976), New England (Crocker 1979), the

Ozark Plateaus and Ouachita Provinces

(Williams 1954), the Southern Appa-
lachians and Cumberland Plateau

(Ortmann 1931), and Mexico (Villa-

lobos 1983).

Extremely useful publications on
crayfishes are Hobbs' key and check-

list to all described crayfishes of North

America (Hobbs 1972a, 1974b).

GEOLOGICAL HISTORY OF
ILLINOIS AND

ZOOGEOGRAPHY OF NATIVE
ILLINOIS DECAPODS

Prior to settlement by Europeans,

Illinois was covered by oak-hickory

forest, maple-basswood forest, and
bluestem prairie. Today much of Illi-

nois has been cleared and developed,

primarily for agriculture and urbaniza-

tion.

The oldest prominent physiographic

features of Illinois are remnants of the

Appalachian Revolution near the close

of the Paleozoic. The intense folding

and faulting during the formation of

the Appalachian Mountains, and the

more moderate folding and tilting to

the west, created the template for the

topographic diversity present today in

southern Illinois (Fenneman 1938).

During the Mesozoic, the seas enlarged,

and by the Cretaceous they inundated

the Coastal Plain as far north as south-

ern Illinois. The subsequent uplifting

of the continent in the late Cretaceous

exposed much of the Coastal Plain, in-

cluding the flatlands persisting today

as swamps along the lower Ohio River

in southern Illinois (Fenneman 1938).

In the late Tertiary the Mississippi

River ran along the western edge, and
the lowermost Ohio River followed the

eastern edge, of Crowley's Ridge (a

ridge on the Coastal Plain of south-

eastern Missouri and northeastern

Arkansas). The two great rivers met near

where Helena, Arkansas, is now (Fenne-

man 1938; Fisk 1944). The Ohio River

was comparatively small, had its head-

waters in southern Indiana and central

Kentucky (Wayne 1952), meandered
across southern Illinois through the

present Cache River valley, and, after

being joined by the Cumberland and
Tennessee rivers, flowed south to its

confluence with the Mississippi. It is

uncertain whether the Tennessee River

joined the Ohio above the entrance of

the Ohip into the Cache lowland or

whether it flowed from its present

mouth down the present course of the

Ohio and Mississippi rivers and joined

the Ohio near southern Tennessee.

The Mississippi River followed much
of its present course in Minnesota and
Wisconsin, then cut through northern

Illinois (Willman & Frye 1970), where

it was joined by its major tributary,

Teays River, and flowed south along the

present course of the Illinois River. The
Teays River began along the western

side of the Blue Ridge Mountains of

Kentucky, Virginia, and West Virginia,

flowed northward to central Ohio, then

turned west across central Indiana and
Illinois through the Mahomet Valley to

the Mississippi (Horberg 1945; Wayne
1952; Teller 1973); or in Indiana turned

south through the present Wabash
Valley to the Ohio River (Fidlar 1948).

It may be that an early Pleistocene ice

advance blocked the original course of



340 Illinois Natural History Survey Bulletin Vol. 33, An. 4

the Teays through the Mahomet Valley

and diverted it into the Wabash Valley

(Wayne 1952).

In the Pleistocene, continental ice

caps advanced in stages and interrupted

the progress of post-Tertiary erosion

cycles. In glaciated areas, topographic

diversity was reduced, valleys were ob-

structed, and river courses were altered.

Areas of low relief, including the Cen-

tral Lowlands, were covered by deep

deposits of drift, forming undulating

till plains.

The earliest glacial invasions, the

Nebraskan and the Kansan, extended

into northern Missouri, southern Il-

linois, southern Indiana, and south-

central Ohio. Streams which formerly

had drained northward into Hudson
Bay and eastward to the Atlantic Ocean
were blocked and diverted to the Mis-

sissippi basin. The lower Teays River

was eliminated, and its tributaries

were diverted into the ancestral Ohio
River (Flint 1971; Hocutt, Denoncourt,

Sc Stauffer 1978), greatly increasing the

area drained by the Ohio.

To the west of the Mississippi River

the Kansan ice cap extended farther

south than other Pleistocene glaciers

and terminated in Missouri, approxi-

mately along the present course of the

Missouri River. East of the Mississippi

River the Kansan ice cap was exceeded

in its southern extent by the later Illi-

noian glacier, which in some areas

reached the present course of the Ohio
River. The Illinoian leveled or buried

in drift most of Illinois. Because it was
the last of the glaciers, drift of the Wis-
consinan covers a large area of Illinois

(Fig. 3) and its ecological impact is

enormous.
As the ice caps retreated, huge quan-

tities of drift were left behind, filling

river channels and valleys. Mounds of

drift (moraines) sometimes reached
heights of 30 m or more and widths of

several kilometers. Moraines generally

were concentric to one another and,
when they formed extensive lakes,

lacked drainage outlets. Ultimately, low

COASTAL PLAIN

Fig. 3.—Glacial boundaries and major ptiys-

iographic features in Illinois.

points of the moraines became drainage

outlets. Water flowing from one lake

to another along the concentric mo-
raines gradually formed streams and,

eventually, complete drainage systems.

With drainage, the process of erosion

began. As sediments were carried into

lakes, the coarser particles (sand and
gravel) were deposited and the smaller

particles (silt and clay) were carried

away. Eventually, the lakes became
marshes and. later, prairies. Thick
layers of sand were sometimes left be-

hind, such as those found today in the

Kankakee Ri\er system of Illinois and
Indiana. Dunes were subsequently
formed as the wind piled sand into

hills.

Throughout the Pleistocene, an area

of southwestern Wisconsin and north-

western Illinois remained imglaciated.



August 1985 Crayfishes and Shrimps of Illinois 341

This "Driftless Area" supports a topo-

graphic diversity, due in part to recent

erosion, absent in the glaciated region.

Interglacial periods, the Aftonian,

Yarmouth, and Sangamon, were char-

acterized by warmer and drier climates

similar to that of today (Braun 1950).

The Wisconsinan ice cap was up to

3 km thick and in some areas, melting,

interrupted by periodic advancement,
took more than 10,000 years (Clark &
Stearn 1960). New drainage systems

eroded the glaciated area, and the junc-

tion of the Ohio and Mississippi rivers

moved progressively northward (Mat-

thes 1933; Fisk 1944). The Great Lakes
were formed as water was impounded ip

the former Laurentian River basin. The
present drainages of Illinois (Fig. 4) are

discussed in detail by Forbes & Richard-

son (1908) and Smith (1971).

Pleistocene glaciers that covered most
of Illinois had profound effects on the

distributions of organisms. The princi-

pal zoogeographic effects were the

elimination of populations (probably

including entire species) and the dis-

placement of species farther south than

they had occurred preglacially. Princi-

pal postglacial zoogeographic events

were the reinvasions of glaciated regions

and the crossing of previously insur-

mountable basin divides through the

newly established drainage systems.

The Illinoian glaciation reached

within 30 km of the northern boundary
of the Mississippi Embayment in south-

ern Illinois (Willman & Frye 1970). A
few species may have maintained pop-
ulations in the surviving uplands, the

Shawnee Hills of southern Illinois

(Fig. 3).

It must have been easy for animals to

invade the new drainages of the gla-

ciated region of Illinois as they became
connected to the existing Ohio and
Mississippi rivers. Postglacial invasions

(cjr reinvasions) undoubtedly were
mostly from the south; i.e., the Ozark
Plateau, Mississippi Embayment, In-

terior Lowland, Appalachian Plateau,

and ephemeral drainages along the

southern edges of the glaciers. Because

all of northern North America (48° and
north) except a large part of Alaska was
covered by ice, the only possible non-
southern postglacial origins of the

decapod fauna of Illinois are east coast

drainages (presumably via the Sus-

quehanna Outlet connecting the eastern

Great Lakes and the Susquehanna
River), the Driftless Area of north-

western Illinois, and the upper Missouri

River drainage. Some species may have

invaded from more than one refugium.

Species likely, because of their present

distributions, to have invaded from the

south are M. ohione, P. kadiakensis,

P. acutus, F. fodiens, and C. diogenes.

All but C. diogenes are sluggish-water

inhabitants that probably invaded the

low-gradient drainages of Illinois from
similar low-gradient streams on the

former Mississippi Embayment. C.

diogenes presumably moved from the

Shawnee Hills and other southern areas

into new drainages to the north.

P. gracilis, O. im?nunis, andO. I'irilis

now occupy western drainages that were

unglaciated, principally the upper
Missouri, and they probably entered

Illinois from the west. The eastward

movement of other grassland and plains

animals during the recent Xerotliermic

Period is discussed by Smith (1957).

O. propinquus now occurs only in

glaciated areas of eastern North America
but is most closely related to species

living in streams in unglaciated south-

ern Ohio, eastern Kentucky, West V'ir-

ginia, and Pennsylvania (Fitzpatrick

1967). It and C. robustus probably in-

vaded Illinois from the east. C. robustus,

as discussed in the species account, has

since retreated from Illinois.

O. stannardi does not now occur in

areas considered to have been Pleis-

tocene refugia, and it may i)e auto-

chthoncjus to the Little Wabash River

system of Illinois. Autochlhonism
would require it to have differentiated

from its closest relatives since the

Pleistocene.

The present decapod fauna of Illinois



342 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Michigan

Fig. 4.— Present drainages of Illinois.



August 1985 Crayfishes and Shrimps of Illinois 343

Table 2.—Native species grouped according to their distributions among physiographic
divisions of Illinois.

Coastal Plain Shawnee Hills Lowland Glaciated Area Statewide

C. puer

C. shujeldtii

P. clarkii

P. viaeinridis

O. tancifer

O. itlinoiensis

O. indianensis

O. kentuckiensis

O. placidus

C. tenebrosus"

M. ohione

P. kadiakensis

P. gracilis

O. propmquui
O. slannardi

O. virilis'

C. robuslus

P. acutus

O. immunis
F. jodiens

C. diogenes

"Also found on the Coastal Plain.

.\lso found in one locality in east-central Illinois.

may be divided into Coastal Plain,

Shawnee Hills, Lowland, Glaciated-

area, and Statewide species groups

(Table 2). The Statewide species group
includes two burrowers (C. diogenes

and F. jodiens) and two sluggish-pool

inhabitants {P. acutus and O. im-

munis).

Those sfjecies found on the Coastal

Plain and in the Shawnee Hills pre-

sumably have been there for a long time

and have undergone little or no post-

glacial dispersal. Those in the glaciated

regions must have invaded or re-invaded

after glaciation (i.e., within the past

10,000-100,000 years) or must have

speciated since then. Illinois' endemic
decapods, O. illtnoiensis and O. slan-

nardi, and its near-endemics, O. ken-

tuckiensis and O. indianensis, occur

south of the boundary of the Wiscon-
sinan glaciation. All except O. slan-

nardi, which occurs on Illinoian glacial

till, are occupants of the Shawnee Hills.

NATURAL HISTORY
Crayfish Life Cycle

During the mating season, form I

males (males in which one or more of

the terminal elements on the gonopods
[first pleopods] are corneous) actively

seek receptive females by grasping other

crayfishes with their chelae. When a

male or nonreceptive female is grasped,

it resists, and the aggressive male re-

leases his catch and continues search-

ing. When a receptive female is grasped,

it stretches the antennae, chelae, and
walking legs forward, curves the end of

the abdomen ventrally and anteriorly.

and becomes motionless. The male
turns the female on her back, holds her

chelae in his, positions his abdomen
over hers (still curved forward), inserts

the ischial hooks on his pereiopods into

the coxal membranes of the pereiopods

of the female (which locks the two cray-

fish together), and inserts the tips of

his gonopods in the annulus ventralis

(seminal receptacle) of the female.

Sperm travel from the reproductive

openings on the bases of the fifth pe-

reiopods along the gonopods to the

annulus ventralis, and mating is com-
pleted. A waxy sperm plug projecting

from the annulus indicates that the

female has recently mated.

Frequencies of form I males among
Illinois collections of crayfishes indicate

that most matings occur between Sep-

tember and March, although consider-

able interspecific variation occurs.

Species of Cambarellus have a high

incidence of form I males throughout

the year.

Sperm are carried by the female until

oviposition (egg laying), which in

Illinois occurs mostly in March, April,

and May but may begin in some species

as early as December or January. In

preparation for oviposition the female

cleans the underside of her abdomen,
mostly through brushing motions of

the fifth pereiopods. During oviposi-

tion the female turns on her back, curls

the abdomen forward, and from glands

on the abdomen secretes a clear, sticky

substance (glair) which fills the area

between the curled abdomen and the

thorax. Sperm and eggs are released



344 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Fig. 5.—Female Orconectes immunis with eggs attached ("in berry").

into the glair from the anmilus ventrahs

and external openings of the oviducts,

respectively. Following oviposition,

the glair hardens and cements the fer-

tilized eggs to the pleopods. With eggs

attached to her abdomen, a female cray-

fish is said to be ovigerous or "in berry"

(Fig. 5).

Eggs are carried by the female for

2-20 weeks, depending on the water

temperature. When the eggs hatch, the

young remain attached to the abdomen
and are carried by the female througfi

three instars. The first juvenile instar

has extremely large eyes, a yolk-filled

carapace, an incomplete abdomen, and
hooked chelae. First instars attach to

the female with the hooked chelae and
by a stalk linking the telson of the instar

to the abdomen of the mother. After

2-7 days first instars molt to second
instars, which are more adultlike but

still lack a fully developed abdomen
and cling to the mother's abdomen by
their chelae. After another 4-12 days,

another molt results in the third instar,

which closely resembles the adidt and
hangs onto the mother with its chelae

and pcreiopods. It may leave the protec-

tion of the mother for short periods.

Subsequent instars are free living.

Growth proceeds through a series of

(i-10 molls during the summer, and
sexual maturity may be attained by

late summer or early fall. Sexual matu-
rity in the male corresponds to a molt

to form I. The first molt following the

mating period returns the male to a

nonieproducti\e state (form II) in

which the gonopods are without cor-

neous tips. Following copulation,

females do not molt until after the

young permanently have left. In Illi-

nois, crayfishes appear to survive a

maximum of two reproductive seasons.

In nonburrowing Illinois crayfishes,

all aspects of their life history occur in

surface waters. Burrowing species spend
variable amounts of time in surface

waters. Adults of P. gracilis and P.

I'iaeviridis leave their burrows and enter

temporary bodies of v\ater to mate. F.

fodiens leaves its burrows to mate, and
females remain out of their burrows
during the period in which they carry

their eggs and young. Young of these

three species remain above ground in

temporary water as long as the water

remains; as the water table recedes below
the stnface, they burrow, .\dults of P.

I'laei'iridis and F. fodiens may be foimd

above ground in Illinois onl\ during
periods of late winter-to-spriiig flood-

ing (January to May). Sexually mature
P. gracilis leav e bmrows on warm lainv

nights but otherwise seldom are found

out of their burrows, .\dults of C. dio-

genes leave their burrows on the banks



August 1985 Crayfishes and Shrimps of Illinois 345

of streams more often than do the

species just mentioned, perhaps to

forage as well as to mate, but do so more
frequently during the mating and egg-

and young-carrying seasons.

Freshwater Shrimp Life Cycle

Females carry eggs attached to their

pleopods between April and August in

Illinois and between February and
October farther south. The eggs hatch,

and free-swimming larvae pass through

six stages in about 3 weeks, described

in detail for Palaemonetes kadiakensis

by Broad &: Hubschman (1963). Larvae

and juveniles increase, and adults de-

crease, in abundance through the sum-
mer. Adults disappear in late summer-
early fall, corresponding to a maximum
life span of about 1 year in Palaemo-
netes kadiakensis and 2 years in Macro-

brachium ohione. The largest adults

mature and reproduce earliest in the

year. Observations on copulation ap-

parently are unrecorded.

KEY TO ILLINOIS SPECIES

Morphological characteristics used shrimps in keys and systematic accounts

to describe and identify crayfishes and are illustrated in Fig. 6-9.

cephalic process

central projection

caudal process

mesial process

A

central projectioi

mesial process

B

Fig. 6.—Lateral view of

Macrobrachium ohione (after

Hoitfiuis 1952).

Fig. 7.—Morpfiology of crayfish gonopods
(after Hobbs 1972a). (A) Mesial (left) and lateral

views of terminal elements of generalized Pro-

cambarus gonopod. (B) IVIesial (left) and lat-

eral views of terminal elements of generalized

Cambarus gonopod. (C) Generalized Orco-
nectes gonopods.

Crayfishes are most easily and accu-

rately identified by using characteristics

of the gonopod (first pleopod) of form I

(breeding) males, and in geographic

areas having many similar species,

accurate identifications of specimens

f)ther than form I males can be nearly

impossible. In Illinois, with only 23

species of decapods, it is possible to

identify most free-living specimens

(including juveniles) to species. Fol-

lowing are two keys, the first is based

on general morphology, the second on
( harac terisiif s of form I male cray-

fishes. In both keys, references to cray-

fish gonopods are to those of form I

males.



346 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

antennule

antenna

antennal scale

acumen of rostrum

marginal spine

- rostrum

suborbital angle

postorbital ridge

hepatic spine

cervical spine

length of carapace —

width of areola

length of areola —

uropod

Fig. 8— Dorsal view of crayfish, illustrating features used in keys and descriptions (after

Hobbs 1972a).



August 1985 Crayfishes and Shrimps of Illinois 347

dactyl

length of palm

hook on ischium

pleopods I

width of palm

Fig 9—Ventral view of crayfish, Illustrating features used in keys and descriptions (after

Hobbs 1972a).



348 Illinois Natural History Survey Bulletin Vol. 33, An. 4

I. Key to Decapods of Illinois

(Key to form I male crayfishes on page 35i)

1. First two pair of legs with chelae; abdomen
compressed laterally (Fig. 6)... (Family Palae-

monidae) 2

1. First three pairs of legs with chelae; abdomen
flattened dorsoventrally (Fig. 8)... (Family

Cambaridae) 3

2. Second pair of legs much longer than the first

pair; 9-13 teeth along upper edge of rostrum

(Fig. 10) Macrobrachium oluone (p. 356)

2. Second pair of legs only slightly longer than

first pair; 6-8 teeth along upper edge of rostrum

(Fig. 11) Palaernoyieles kadiakensis (p. 359)

3. Areola wide; narrowest width about 20-25 per-

cent of length (Fig. 12); rostrum flat dorsally;

small, adult carapace length never more than

16 mm (32 mm total length). . .(Genus Cam-
carellus) 4

Areola obliterated to moderately wide but nar-

rowest width never more than 20 percent of

length (except in Orconectes propinquus and

O. stannardi); rostrum conca\e dorsally; maxi-

mum carapace length much more than 16

mm 5

4. Terminal elements of gonopod cur\ed (Fig. 13);

margins of rostrum slightly convex, barely con-

verging anteriorly; annulus vcntralis extends

anteioventialh (Fig. 14) Catnbarellus

jjury (p. 366)

4. Terminal elements of gonopod straight (Fig.

15); margins of rostrum straight, strongly con-

verging anteriorly; annulus ventralis extends

ventrallv (Fig. 16) Cambarrllus shufrldtii

(p. ;i63)

Fig. 10.

Fig. 11.

Fig. 12.

c
Fig. 13.

Fig. 14.

Fig. 15.
./^

Fig. 16.



August 1985 Crayfishes and Shrimps of Illinois 349

5. AiTola linear to obliterated (Fig. 17) 6

5. Areola narrow to wide 10

6. Rostrum deeply excavated, with acumen longer

than basal margin of rostrum (Fig. 18)

Orconectes lancijer (p. 400)

6. Rostrum shalknvly excavated; acumen much
shorter than margin of rostrum 7

7. Chela long and narrow, maximum width less

than one-third of length (Fig. 19); acumen and
marginal spines of rostrum well-developed (Fig.

20); a longitudinal blue stripe along underside
of abdomen (fades in preservative) Pro-

cambarus clarkii (p. 381)

Fig. 17.

Fig. 18.

Fig. 19.

Fig. 20.

7. Chela wide, maximum width more than one-

third of length; small acumen, no marginal

spines on rostrum; no blue stripe on abdo-

men 8

1!^..

w Fig. 22.

Fig. 21.

8. Areola linear only at midlength (Fig. 21); gono-

pod terminates in small straight elements (Fig.

22); annulus ventralis subrectangular, elevated

laterally Procambarus gracilis (p. 370)

8. Areola linear through most of length (Fig. 23);

gonopod terminates in two large curved ele-

ments (Fig. 24); annulus ventralis wider than

long, elevated posteriorly 9 Fig. 24.



350 Illinois Natural History Survey Bulletin \'o1. 33. An. 4

9. Suborbital margin of carapace smooth to slight- ^^^
ly angular (Fig. 25); opposable margin of mov- ^^ y^
able finger of chela with deep concavity (absent ^ \r~^

'^'^ ^^

in regenerated chela) in proximal one-half (Fig.

26) Fallicambarus jodiens (p. 422)

Fig. 26.

9. Suborbital margin of carapace angular (Fig. 27);

opposable margin of dactyl of chela without ^:^^^^^^^ Z^
deep concavity (Fig. 28) Cambarus y^

PI 27
diogenes (p. 434) ^\^

Fig 28.

Fig. 29.

10. Margins of rostrum without large spines (Fig.

29) 11

10. Margins of rostrum with large spines (Fig. 30)

15

11. Carapace laterally compressed: chela long and
narrow, maximum width less than one-third of

length 12

11. Carapace dorsoventrally flattened; chela wide,

maximum width more than one-third of length

Il4

12. Gonopod terminates in large curved elements

(Fig. 31); annulus \entralis wide, with fossa far

to one side (Fig. 32) Orconectes immunis
(p. 388)

12. Gonopod lerniinates in very short elements; Fig. 31.

annulus veniralis with fossa more centrally

located 13 Fig. 32.

Fig. 30.

i



August 1985 Crayfishes and Shrimps of Illinois 351

13. Margins of rostrum ele\ated, strongly converg-

ing to acumen (Fig. 33); narrow areola (Fig.

33) Procambarus acutiis (p. 376)

13. Margins of rostrum not elevated; rostrum more

rounded anteriorly (Fig. 34); wide areola (Fig.

34) Procambarus viaeviridis (p. 378)

14. Base of fixedfingerof chela with deep dorsal and

ventral impressions (Fig. 35); margins of ros-

trum converge anteriorly (Fig. 36) Cam-
barus robustus (p. 439)

14. Base of fixed finger of chela without deep im-

pressions (Fig. 37); margins of rostrum nearly

parallel, barely converging anteriorly (Fig. 38)

Cambarus tenebrosus (p. 428)

15. Margins of rostrum distinctly concave (Fig. 39)

^ 16

15. Margins of rostrum straight (Fig. 40) 18

16. Central projection of gonopod large and blade-

like, curved at right angle to shaft (Fig. 41);

annulus ventralis with fossa to side Cam-
barus rusltcijortnis (p. 432)

16. Clentral projection of gonopod not large and

bladelike; annulus ventralis with fossa centrally

located 17

17. Dorsal (cephalic when lifted from body) surface

of gonopod with prominent shoulder (Fig.

42) Orconectes ruslicus (p. 412)

Fig. 33,

Fig. 34,

Fig. 38.

Fig. 37.

Fig. 40.

Fig. 39

Fig. 41

Fig. 42.



352 Illinois Natural History Survey Bulletin Vol.33. Art. 4

17. Dorsal surface of gonopod without prominent

shoulder (Fig. 43) Orconectes placidus

(p. 404)

18. Areola distinctly narrows just anterior to mid-

length (Fig. 44); gonopod reaches coxa of cheli-

ped with abdomen flexed; no black band on
fingers of chela Orconectes virilis (y). AM) ^b^^j^ !

Fig 43.

18. Areola remains fairly wide throughout (Fig. 40); Fig. 44.

gonopod does not reach coxa of first pair of

walking legs; black band (fades in preservative)

near tips of fingers of chela 19

19. Rostrum deeply excavated medially, with mar-

gins distinctly converging anteriorly (Fig. 45)

Orconectes illinoiensis (p. 386)

19. Rostrum shallowly excavated, margins barely
p| ^^

converging anteriorly 20

20. Rostrum without median carina (Fig. 46);.

Orconectes kentuckiensis (p. 396)

20. Rostrum with median carina (small in O. in-

dianensis) (Fig. 47); 21

21 . Mesial process of gonopod with spur on caudal

surface (Fig. 48) Orconectes stnnnardi

(p. 415)

21. Mesial process of gonopod without spur 22

22. Rostrum with large median carina (Fig. 49);

gonopod with tips of elements barely di\erging Fig. 49.

(Fig. 50); Orconectes propinquus (p. 406)

Fig 48.

/
Fig. 47.

Fig. 50.

/

22. Rosinun with small meilian carina (Fig. 51);
p| ^^

gonopod with tips of elements stroiigh di\erg-

ing (Fig. 52).... Orcuneclrs indiiinensis (p. 394) Fig. 52.



August 1985 Crayfishes and Shrimps of Illinois 353

II. Key to Illinois Crayfishes Based on Form
I Males (i.e., males with corneous ter-

minal elements on the gonopods)
1. Ischia of second and third peieiopods with

hooks (Fig. 9). . .Genus Cambarellus 2

1. Ischia of second pereiopods without hooks ....3

2. Terminal elements of gonopod straight (Fig.

53) Cambarellus shufeldtii (p. 363)

2. Terminal elements of gonopod curved at about
right angle to shaft (Fig. 54) Cambarel- ^'^^ 53. Fig 54

lus puer (p. 366)

3. Central projection of gonopod large and blade-

like, curved at right angle to shaft (Fig. 55). .

.

Genera Fallicambarus and Cambarus 4

2. Central projection of gonopod not bladelike. .

.

Genera Orconecles and Procambarus 8
Fig. 55

4. Areola linear (Fig. 56) 5

^ * 1 1 ^ Fig. 56.
4. Areola narrow to wide 6

5. Suborbital margin of carapace smooth to slight-

ly angular (Fig. 57); opposable margin of mov-
able finger of chela with deep concavity (absent Fig. 57.

in regenerated chela) in proximal one-half (Fig.

58) Fallicambarus fodiens (p. 422)

Fig. 58.

Suborbital margin of carapace angular (Fig. 59);
'^ ^

opposable margin of movable finger of chela

without deep concavity (Fig. 60) Cam-
barus diogenes (p. 434)

Base of fixed finger of chela wiili dccj) dorsal

and ventral imjiressions (Fig. 61) Cam-
barus robuslus (p. 439) "^'9 ^1



354 Illinois Natural History Survey Bulletin Vol. 33, An. 4

6. Base of fixed finger of chela without deep im-

pressions 7

7. Margins of rostrum concave, with spines (Fig.

62) Cambarus rusticiformis (p. 432)

7. Margins of rostrum straight, without spines

(Fig. 63) Cambarus tenebrosus (p. 428)

8. Gonopod terminates in two elements (Fig. 64)

. . .Genus Orconectes 9

8. Gonopod terminates in more than two, very

short elements (Fig. 65). . .Genus Procambarus
18

Fig. 62

Fig. 63.

9. Areola obliterated (Fig. 66); rostrum deeply H /
excavated, with acumen longer than basal ^V '

margin of rostrum (Fig. 66) Orconectes

lancifer (p. 400)

9. Areola narrow to wide; acumen much shorter

than basal margin of rostrum 10 ^^9- 65.

/ Fig. 66.

10. Both terminal elements of gonopod curved at

right angle to shaft (Fig. 67); annulus ventralis

with fossa far to one side (Fig. 68) Orco-
nectes inimunis (p. 388)

10. One or both terminal elements of gonopod ^ft '^'9 ^8.

straight or only slightly curved; annulus ven-

tralis with fossa more centrally located 11

Fig. 67.

11. Central projection constitutes one-fourth or

less of total length of gonopod (Fig. 7) 12

11. Central projection constitutes more than one-

fourth of total length of gonopod (Fig. 7) ...16

12. Terminal elements of gonopod distinctly diver-

gent (Fig. 69 & 70) 13 Fig.'69.



72.

August 1985 Crayfishes and Shrimps of Illinois 355

12. Terminal ek-ments of gonopod nearly parallel

(Fig. 72 & 73) .'. 14 u //

13. Terminal elements of gonopod curved (Fig.

69) Orconectes kentuckiensis (p. 396)

13. Terminal elements of gonopod nearly straight

(Fig. 70) Orconectes indlauensis (p. 394)

14. Rostrum with median carina (Fig. 71) 15

14. Rostrum without median carina Orco-

nectes illinoiensis (p. 386) Fig. 71

15. Mesial process of gonopod with spur on caudal

surface (Fig. 72) Orconectes stannardi

(p. 415)

15. Mesial process of gonopod without spur (Fig.

73) Orconectes propinquus (p. 406) M
p| 73

16. Both elements of gonopod curved (Fig. 74);

areola distinctly narrows anteriorly (Fig. 75);

no black bands on fingers of chela Orco-

nectes I'irilis (p. 417) Fig. 74.

16. Mesial process of gonopod not curved; areola

remains fairly wide throughout; black, band
(fades in preservative) near tips of fingers of

chela 17

Fig. 75.

Fig. 76.

17. Dorsal (cephalic when lifted from body) surface

of gonopod with prominent shoulder (Fig. 76)

Orconectes rusticus (p. 412)

17. Dorsal surface of gonopod without prominent
shoulder (Fig. 77) Orconectes placidus

(p. 404)

18. Dorsal surface of gonopod with prominent
shoulder (Fig. 78); cephalic process a large lobe

(Fig. 78) Procambarus clarkii (p. 381)

18. Dorsal surface of gonopod without shoulder;

cephalic process small 19 Fig. 78.

Fig. 77.



356 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

19. Areola linear at midlength (Fig. 79); hooks on

ischia of third pereiopods only (Fig. 9)

Procambarus gracilis (p. 370)

19. Areola narrow but not linear (Fig. 80 & 81);

hooks on ischia of third and fourth pereio-

pods 20

20. Margins of rostrum elevated, converging to

acumen (Fig. 80); narrow areola (Fig. 80)

Procambarus acutus (p. 376)

20. Margins of rostrum not elevated; rostrum more

rounded anteriorly (Fig. 81); wide areola (Fig.

81) Procambarus viaeviridis (p. 378)

Fig. 79

Fig. 80. Fig. 81.

SYSTEMATIC ACCOUNTS
FAMILY PALAEMONIDAE

Both shrimps native to Illinois are

members of the family Palaemonidae,

which is worldwide in distribution.

Macrobrachium ohione, with 9-13

teeth along the upper edge of the ros-

trum, is easily separable from Palae-

monetes kadiakensis, which has only
6-8 (almost always 7) teeth. M. ohione,

which reaches 100 mm in total length

(tip of rostrum to tip of telson), also is

much larger than P. kadiakensis, which
reaches a maximum length of only

about 50 mm.

Genus Macrobrachium Bate

Macrobrachium Bate 1868

Species of Macrobrachium, referred

to as river shrimps, differ from species

of Palaemonetes by possessing a hepatic

spine, lacking a branchiostegal spine,

and having the second pair of legs much
longer than the first pair (in Palae-

monetes the second pair is only slighth

longer than the first pair).

Although Macrobrachium contains

aboiii 100 species worldwide (35 in the

western hemisphere), only four (A/.

ohione, M. acanthurus. M. carcinus,

and M. oljersii) are found in the fresh-

waters of the eastern United States

(Hedgpeth 1949; Holthuis 1952). M.

ohione is the only species of Macro-

brachium found in the Mississippi

River system.

Macrobrachium ohione (Smith)

(Fig. 82)

Palaemon Ohionis Smith 1874

Palaemon sallei Kingsley 1882

Description.—Holthuis (1952) dis-

tinguished M. ohione from other

American species of Macrobrachium
by this combination of characteristics:

carpus of second legs as long as or

longer than merus; telson with a dis-

tinct posterior margin (rather than

gradually tapering toward a slender

tip); second chelae of adult male equal

or nearly equal to one another in size

(some species are bilaterally asymmet-

rical with the chela on one side much
larger); no tubercles along cutting

edges of fingers of second chela of adult

male; cutting edges of fingers of large

chela of adult male with one or two

fairly large teeth proximally; eggs num-
erous and small (about 0.5 mm in diam-

eter); second pair of legs of adult male

with velvety pubescence on some or all

joints; rostrum with styliform apex (and

no teeth distally).

M. ohione is pale gray with light blue

spots and a blue abdomen (Hedgpeth

1947, 1949). .\duli females average

larger than adult males and ha\e much



August 1985 Crayfishes and Shrimps of Illinois 357

Fig. 82.—Lateral view of Macrobrachium ohione (after Holthuis 1952).

longer second legs (Holthuis 1952).

Females reach about 100 mm in length,

males about 70 mm (Hedgpeth 1949;

Truesdale & Mermilliod 1979).

Distribution and Habitat.—M.
ohione occupies freshwater habitats

along the Atlantic coast from Virginia

to Florida, along the Gulf Coast from

Alabama to Texas, and north in the

Mississippi and Ohio river systems to

Oklahoma, Missouri, Illinois, Indiana,

Fig. 83.—Total distribution of Macrobrach-
ium ohione.

and Ohio (Fig. 83). Coastal populations

inove into estuaries in spring (Gunter

1937; Hedgpeth 1949; Reimei, Strawn,

Sc Dixon 1974).

In Illinois, M. ohione has been re-

corded from Cairo, Alexander County
(Forbes 1876); Grand Tower, Jackson
County (Forbes 1876); Chester, Ran-
dolph County (McCormick 1934); and
Shawneetown, Gallatin County (Hedg-
peth 1949) (Fig. 84). Although Hedg-
peth (1949) and Holthuis (1952) cite

Luce (1933) as recording M. ohione
from the lower Kaskaskia River. Illi-

nois, the reference is actually to its use

as fish bait.

Forbes (1876) described A/, ohione as

"abundant at Cairo, where it is fre-

quently eaten" and reported second

handedly its presence in the Mississippi

River system from St. Louis to New
Orleans. It aj^parently was common
in the Mississippi River as recently

as the 1930's, when McCormick (1934)

described the successful use of "shrimp
sets" at Chester. Shrimp sets were wil-

low or Cottonwood branches set along
the river's edge and bent so that their

leaves were under water. As shrimj) fed

on the leaves they weie dipneited by

fishermen.

In the lUintjis Natural History Survey

collection are six series of M. ohione
from Illinois, including one made by

S. A. Forbes at Caircj (undated). The
five collections with locality data.



358 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

(Mount Carmel, Wabash County, 1892;

Mississippi River, Grand Tower, Jack-

son County, 1932 and 1944; Mississippi

River, Missouri River Station, Madison
County, 1944; and Mississippi River,

1 mi S Cairo, Alexander County, 1962)

are represented on the distribution map
(Fig. 84). No M. ohione were found
during the present survey (1972-1982).

Although perhaps still present in the

state, the species obviously has under-

gone a tremendous reduction in popu-
lation. Little information on the ecol-

ogy of the species in Illinois is available,

but its decline presumably is attribut-

able to the loss of suitable habitats as

a result of the excessive modifications

(especially channelization, impound-
ment, and drainage of bottomland
lakes) of Illinois' largest rivers.

Life History.—In the Mississippi

River at Chester, McCormick (1934)

Fig. 84 —Distribution of Macrobrachium
ohione in Illinois. Large circles = pre-1900
collections, small circles = 1932-1949 collec-
tions, black dot = collection made in 1962.

counted 8,000 eggs on an 84-min female

and observed that ovigerous females

ranged from 34 to 90 mm long. Among
Illinois Natural History Survey col-

lections of Illinois M. ohtone (all made
between May and October), ovigerous

females are present only in a collection

made 13-14 May 1932.

In Louisiana, Truesdale Sc Mermil-
liod (1979) found ovigerous females

(50-93 mm in total length) from March
through September. Five females, rang-

ing from 54 to 80 mm, were carrying

6,273-24,800 eggs. Eggs were ai)out

0.5 mm across, bright orange when first

laid, and brown at later stages. Huner
(1977) found M. ohione at Port Allen,

Louisiana, to range from 17 to 92 mm
long, to average 30.6 mm (N = 7,058).

and to live a maximum of 2 years. Ovi-

gerous females (N = 88) ranged from 27

to 92 mm and averaged 66 mm.
In the springs of 1969-1971, Reimer,

Strawn, & Dixon (1974) studied move-
ments of M. ohione into Galveston

Bay, Texas. Increased movement was
associated with rainfall, and salinities

as high as 15 percent seemed to prevent

further movement. The first individuals

to appear in the bay were males and
females without eggs. Females carrying

eggs first appeared in late March. Fe-

males averaged larger than males, and
only the largest females (52-82 mm)
bore eggs.

M. ohione feeds on both plant and
animal material (McCormick 1934;

Gunter 1937; Darnell 1958; Truesdale

& Mermilliod 1979) and in turn is fed

upon by several predators, including

flathead catfish [Pylodiclis olii'aris)

and white bass (Morone chrysops)

(Bryan, Truesdale. &: Sabins 1975).

Genus Palaemonetes Heller

Palaemonetes Heller 1869

Of the approximately 17 species of

Palaemonetes (referred to as prawns,

glass shrimp, and freshwater shrimp)

in the western hemisphere, onlv P.

kadiakcnsts occurs in Illinois. P. palu-

dosus is widespread in the eastern

I'nited States and along the Gulf Coast



August 1985 Crayfishes and Shrimps of Illinois 359

Fig. 85— Lateral view of Palaemonetes kadiakensis.

as far west as eastern Texas, but it does

not enter the Mississippi River system.

In addition to P. kadiakensis and P.

paludosus, the only freshwater species

in the United States are highly localized

spring- and cave-inhabiting forms in

Texas (P. antrorum, P. holthuisi, and P.

texanus) and Florida (P. cummingi)
(Strenth 1976).

Palaemonetes kadiakensis Rathbun
(Fig. 85)

Palaemonetes kadiakensis Rathbun
1902

Description.— P. kadiakensis is the

only species of Palaemonetes with three

apical setae on the appendix masculina

(Fig. 86) occurring in the freshwaters

of the I'nited States (Fleming 1969).

Rostrum straight; upper margin convex

with 6-8, usually 7, teeth; lower margin
with 2-3 teeth. Carapace with antennal

and branchiostegal spines; branch-

iostegal spine below branchiostegal

groove. Abdomen humped at third

segment; sixth abdominal slightly

less than twice as long as fifth segment,

slightly shorter than telson. Anterior

pair of dorsal spines on telson usually

distinctly behind middle of length,

posterior pair near distal margin. Eyes

large, pigmented. Lateral antennular

flagellum with rami fused for 11-23

articles; free portion of shorter ramus

with 3-8 articles. Scaphocerite about

three times as long as wide, lamella

overreaching distolateral tooth.

Living specimens are transparent

with green eyes, red-brown antennae,

and many very small red-brown specks

on the body. The internal organs are

readily visible, and a bright green vege-

tation-filled intestine is often a prom-

inent feature. The species reaches a

Fig. 86.—Appendices masculina and interna

(left) and entire second pleopod (right) of male
Palaemonetes kadiakensis (after Meehean
1936).



360 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

maximum length of about 53 mm total

length (Meehen 1936).

Distribution and Habitat.

—

P. kadia-

kensis occupies sluggish heshwater

habitats from Minnesota and the shores

of Lakes Ontario, Erie, and Michigan

south in the Mississippi River system

to the Gulf of Mexico, and Gulf Coast

drainages from northeastern Mexico
(Nuevo Leon) to northern Florida (Hol-

thuis 1952) (Fig. 87). Although the

Fig. 87.—Total distribution of Palaemo-
netes kadiakensis.

locality given on the label accompany-
ing the type specimen is Kodiak Island.

Alaska, it is doubtful that the species

ever occurred in Alaska (Holthuis 1952).

P. kadiakensis now occurs through-

out the southern one-fourth of Illinois,

in backwaters along the Mississippi

River, in backwaters of the Illinois

River at least as far north as Bureau
County, and in Wolf Lake (Lake Mich-
igan drainage) in Cook County (Fig.

88). It abounds in swamps (Fig. 89)

and swamplike streams on the Coastal

Plain of Illinois and is common in

standing- and sluggish-watei habitats

as far north as Salem. It is uncommon
in the Illinois River and in Wolf Lake.

Fig. 88.— Distribution of Palaemonetes
kadiakensis in Illinois. Open circle = pre-1898

record for the Kankakee River; black dots =

1972-1982 collections.

Forbes (1876) recorded P. kadiakensis

(as P. exilipes) only from the Illinois

River but described it as being very

(ommon. A specimen in the I'.S. Na-

tional Museum of Natural History

documents its former occurrence at

Kankakee. Kankakee County (pre-1898.

exact date unknown), a localitv well

outside the present range.

P. kadiakensis almost always is asso-

ciated with, and is most abundant in.

li\ing a(]ualic \egetation. Its reduction

in distribution and abundance in Il-

linois probably is attributable to in-

creased turbidiiv and .sedimentation

and the resultant loss of vegetation.

Beds of emergent and submerged \ege-

t.iiion once were common throughout

Illinois but now are rarely encountered.

The loss of vegetation is also one of tire



August 1985 Crayfishes and Shrimps of Illinois 361

*g*:-HL.

Fig. 89.—Mermet Swamp, Massac County, Illinois (8 October 1984). Large populations of

Palaemonetes kadiakensis and P. clarkii occur here.

main causes of reductions in popula-

tions of Illinois fishes (Smith 1979).

Life History.— Reproduction in

Illinois, as indicated by the presence of

ovigerous females, occurs from April to

August (Table 3). In Louisiana the

reproductive period extends from Feb-

ruary to October (Meehean 1936; White
1949), and in central Missouri (where

the species is introduced) from mid-May
to August (Nielsen k Reynolds 1977).

In Illinois collections, ovigerous

females range in total length from 30

to 39 mm. Eggs (embryos) on 15 females

numbered 22-137 (mean, 86.6) (Table

4). The relationship (Model II regres-

sion) between the number of eggs (N)

and total length (L) was N = -230.16

+ 9.19L, r = 0.674, and between the

number of eggs and the weight of the

female (W) was N = 10.78 + 318.21W,
r = 0.694. Nielsen &: Reynolds (1977)

found that the number of eggs varied

from 20 to 76 on females 25-36 mm in

length and equalled -111.43 + 5.29 L,

r- = 0.64. Meehean (1936) found as many
as 154 eggs (on a 49-mm female).

Eggs are spherical, orange, and about

1.0 mm in diameter. The egg mass con-

stituted an average of 11.2 percent of

the weight of the female (without the

eggs) in 15 Illinois females (Table 4).

Females may produce more thair one
brood per season (Broad &: Hubschman
1963; Nielsen & Reynolds 1977). The
incubation period lasts 24-28 days at

18.5°-24°C. Detailed accounts of lar-

Table 3.— Illinois collections of Palae-

monetes kadiakensis.



362 Illinois Natural History Survey Billetin Vol. 33. Art. 4

Table 4 —Relationship between size of female and the number and weight of eggs (em-

bryos) in Illinois-collected Palaemonetes kadiakensis.



August 1985 Crayfishes and Shrimps of Illinois 363

suture; except in some species of FalU-

cambarus, the telson always is divided

in North American cambarids.

Genus Cambarellus Ortmann

Cambarellus Ortmann 1905

Gonopod with three terminal ele-

ments; central projection not large and
bladelike. Ischia of second and third

pereiopods of male with hooks.

Species of Cambarellus are distrib-

uted throughout the southern United

States and Mexico, generally in swamps
and other standing- or sluggish-water

habitats. They are "dwarf" crayfishes,

reaching a maximum total length of

about 30 mm. Two of the 17 recognized

species of Cambarellus occur in south-

ern Illinois. Fitzpatrick (1983) revised

Cambarellus, proposing the recogni-

tion of three subgenera.

Cambarellus shufeldtii (Faxon)

(Fig. 90)

Cambarus Shufeldtii Faxon 1884

Description.—Rostrum broad, flat,

often deflecting downward anteriorly;

margins straight, strongly converging

anteriorly, ending in large spines;

acumen moderately large. Carapace

compressed, with cervical spines; sub-

orbital margin angular. Areola wide,

narrowest part about 19-24 percent of

length. Chela narrow and long, smooth;

palm without tubercles. Form I gono-

pod terminates in three elements, all

distally directed (not curved): sclerotized

central projection, nonsclerotized

mesial process, and nonsclerotized

caudal process. Dorsal color variable,

from rust red to light brown with two
dark brown stripes or rows of spots on
either side of the areola extending down
the abdomen.

C. shufeldtii appears to have no ob-

viously close relatives, being the only

species in the genus with straight ter-

minal elements on the gonopod and the

only member of the subgenus Dirigi-

cambarus (Fitzpatrick 1983).

Distribution and Habitat.— C.

shufeldtii occupies bodies of sluggish

water, mostly on the Coastal Plain, from

southern Illinois to southwestern Ala-

bama and eastern Texas (Fig. 91). In

Illinois, C. shufeldtii is known only

from Alexander, Jackson, Massac,
Pulaski, and Union counties in both

the Mississippi and Ohio basins. Most
localities are on the former Mississippi

Embayment, but the species also as-

cends the lower M ississippi River Valley

and the lower Big Muddy River to about

Sand Ridge in Jackson County (Fig. 92).

C. shufeldtii was first collected in Il-

linois at Cairo by Robert Kennicott

(Faxon 1914). Brown (1955) found the

species in five sloughs and ditches in

Alexander and Massac counties. The 28

collections made in the present survey

were from cypress swamps, sloughs, and
backwaters. C. shufeldtii is especially

common in the heavily vegetated LaRue
Swamp-Wolf Lake complex in Union
County. C. shufeldtii and C. puer have

not been found together in Illinois and
apparently compete for suitable habi-

tats. In Gulf Coast streams C. shufeldtii

is supplanting C. puer (see C. puer

account).

C. shufeldtii was probably more
common and widespread in extreme

southern Illinois prior to the extensive

clearing of swamps and river flood-

plains. Brown (1955) mentioned an
earlier collection of a "dwarf crayfish"

near Shawneetown (Gallatin County)
but was unable to document the occur-

rence of Cambarellus that far northeast.

In view of the occurrence, or former

occurrence, of several swamp-inhabit-
ing fishes (Fundulus dispar, Elassoma
zonatum, Lepomis punclatus, and L.

symmetricus [Smith 1979]) that far

northeast, or even into the lowlands

of the lower Wabash River drainage,

the presence of C. shufeldtii or C.

puer in the same area is possible.

In Louisiana, C. shufeldtii lives in

clear, shallow (less than 40 cm deep),

permanent, sun-exposed, mud-bot-
tomed, vegetated bodies of water (Penn

1950). C. shufeldtii characteristically

does not burrow but may survive peri-

ods of drought in subterranean (ells

(Penn 1950). Apparently the trayfish



364 Illinois Natural History Survey Bulletin Vol. 33, An. 4

i

Fig. 90—Cambare//us shufeldtii. A, dorsal view of carapace; B, dorsal view of right chela:
C, annulus ventralis; D, mesial viewof gonopod of form I male; E. lateral view of gonopod of form
I male; F. lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 365

Fig. 91.—Total distribution of Cambarellus
shufeldtii.

excavates a chamber in the mud bottom
of the slough or swamp as drying occurs

and then seals the top of the chamber
to prevent desiccation.

Life History.—Form I males are

present in Illinois collections (Table 5)

during most months and peak in occur-

rence in December, February, and
March. In Louisiana, Penn (1942, 1950)

found form I males in all months except

September, with peaks in January,

February, and July. Presumably,
mating in C. shufeldtii may occur at

anytime but peaks in winter in Illinois

and in winter and summer in Louisiana.

Females carrying eggs were found in

Illinois from February to May, and
peaked in occurrence in March (Table

5); females carrying young have been

found in Illinois in April, June (Table

5), and July (Brown 1955). In Louisiana,

females with eggs or young are jjiesenl

in every month, with strong peaks in

January-Mardi and June-July (Penn

1942, 1950; Lowe 1961), again suggest-

ing two peaks of repiodut ti\i' activity

in the southern part of the range.

Nine Illinois females, ll.tJ-14.2 mm

Fig. 92.— Distribution of Cambarellus shu-
feldtii in Illinois; black dots = 1972-1982 col-

lections.

CL, collected in February and March
were carrying 47-99 (mean, 80.1) eggs

averaging 1.1 mm in diameter. The re-

lationship between numbers of eggs (N)

and carapace length (CL) is N = —539.0

+ 558.9 log CL, r = 0.86. Four females,

12.4-13.5 mm CL, collected in April

1974 were carrying 15-74 (mean, 44.8)

young. The decline from an average of

80.1 eggs to an average of 44.8 young
suggests a 44 percent mortality during

egg and early instar stages. Penn (1942)

found the number of eggs or young on
a female to increase with the carapace

length of the female, with females 8.5

mm averaging 27 offsjiring and those

1 1 mm averaging 54 offsjjring. \n oxer-

all average of 34 offspring per female

{N = 100) in Louisiana (Penn 1942) is

about one-half the average number of

()ns|)riiig (69.2) [jer female (;V = 13) in

Ilhncjis; hc)wever, the comparison is



366 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Table 5.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and

females carrying young, in Illinois collections of Cambarellus shufeldtii.



August 1985 Crayfishes and Shrimps of Illinois 367

Fig. 9A~-Cambarellus puer A, dorsal view of carapace; B. dorsal view of right chela; C,
annulus ventralls; D, mesial view of gonopod of form I male; E, lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male



368 Illinois Natural History Survey Bulletin Vol. 33, An. 4

margins convex, barely converging

anteriorly, ending in large spines;

acumen moderately large. Carapace

compressed, with cervical spines; sub-

orbital margin angular. Areola wide,

narrowest part about 25 percent of

length. Chela narrow and long, smooth;

palm without tubercles. Form I gono-

pod terminates in three elements: sclero-

tized central projection, nonsclerotized

mesial process, and nonsclerotized

caudal process, all curved at sharp angle

(about 45°-90°) to principal axis of

gonopod. Color as in C. shujeldtii.

The closest relatives of C. puer are C.

schmitti and C. lesliei (see Fitzpatrick

&: Laning 1976), two occupants of the

Gulf Coastal Plain from Mississippi

to Florida. C. puer, C. schmitti. C.

lesliei, C. diminutus, C. blacki, C.

ninae, and C. texanus all are members
of the subgenus Pandicambarus (Fitz-

patrick 1983).

Variation in morphological charac-

teristics of C. puer was studied by

Chambers, Payne, & Kennedy (1979).

Three populations were separable from
one another but not given taxonomic
status. Illinois populations are part

of a larger population extending along

the Mississippi River and across south-

ern Louisiana. In general, individuals

in the east are larger than those in the

west; females are larger and have

shorter, broader chelae and shorter

rostra than do males.

Distribution and Habitat.

—

C. puer
ranges from southern Illinois and
southeastern Missouri to the Gulf Coast

of Louisiana and the lower Colorado
River drainage of Texas (Fig. 95). All

populations are on the Coastal Plain.

In Louisiana, C. puer occurs most
frequently in shallow (less than 40 cm
deep), clear, permanent, sun-exposed,

mud-bottomed, vegetated water bodies

(Penn 1950).

C. puer was first found in Illinois in

1973 (Page & Burr 1973) and now is

known fr(jm seven sites in the Missis-

sippi and Ohio basins in I'nion, John-
son, and Alexander (ouniies (Fig. 96).

In Illinois, it occupies cypress swamps

(Fig. 97), effluent streams, and lowland

areas which probably were swamps
prior to being cleared. \\\ but one col-

lection from a roadside ditch were made
in permanent water bodies, and most
specimens were found among living or

dead vegetation. C. puer may be more
widespread on the Coastal Plain of Il-

linois than present records indicate and
almost certainly was more widespread

and common prior to the drainage of

swamps and lowlands.

C. puer and C. shujeldtii were col-

lected at 23 sites in Illinois, mostly

in Coastal Plain swamps, but never

were collected together. Competitive

exclusion among species of Cambarel-

lus has been documented in Gulf Coast

areas (Penn & Fitzpatrick 1962. 1963)

and apparently is operating in Illinois.

C. puer and C. shujeldtii seem unable

to coexist and, at least along the Gulf

Coast, C. shujeldtii has supplanted

C. puer at several localities within

historic times (Penn &: Fitzpatrick 1962.

1963). C. shujeldtii was found experi-

mentally to be dominant o\er C puer

(i.e., C. puer retreats following contact

with C. shujeldtii) (Penn &: Fitzpatrick

1963), suggesting that in nature C.

shujeldtii agressi\ely displaces C. puer

from certain habitats.

Life History.—Louisiana data sug-

gest IWC3 ieproducti\e periods (winter

and summer) (Penn 1950; Black 1966).

although form I males can be found

in all months (Black 1966). Illinois

data are seasonally incomplete (Table

6), but two reproductive peric:)ds. some-

what later (i.e.. late winter-spring and
fall) than in Louisiana, may also occur

in Illinois. In Louisiana, form I males

peak in occurrence from December to

March (abc^ut 60-95 percent of all males)

and from July to .\ugust (about 45-75

percent) (Penn 1950: Black 1966). In

the available Illinois collections (Fable

6), form I iiiak's are present February-

May and in October. In Louisiana, form

I C. puer males measure 7.2-12.0 mm
CL and weigh 75.4-412.1 mg (Black

1966). Fhirteen or 14 molts are required

to reach sexual maturity, with a mean



August 1985 Crayfishes and Shrimps of Illinois 369

Fig. 96,—Distribution of Cambarellus puer
in Illinois; black dots = 1972-1982 collections.

growth increment of 0.45 mm 'molt

(Black 1966). .Sixteen form I males col-

lected in Illinois ranged from 7.7 to

12.8 and averaged 10.4 mm CL.
In Louisiana, females carrying eggs

or young occur January-April, and
August-September (Penn 1950). In

Illinois, females carrying eggs were
collected Marcfi-May, and females
carrying young have been collected in

May (Table 6). Ten Illinois females

carrying eggs (collected March-May)
ranged from 11.0 to 14.6 mm and av-

eraged 12.2 mm; five females carrying

young (in May) ranged from 10.6 to 11.5,

and averaged 10.9 mm CL.

Six Illinois females, 11.0-14.6 mm
CL, had 52-98 (mean, 82.3) eggs av-

eraging 1.1 mm in diameter. Five fe-

males, 10.6-11.5 mm CL, had 15-48

(mean, 30.8) young attached; the young
on the female with 48 yrning were first

instars, the 15-36 young on the other

females were later instars, suggesting

a high mortality while they are carried

by the mother.

Of the 60 C. puer collected in Illinois,

30 were males (16 were form I), and 30

were females. Longevity is 15-18

months (Black 1966).

Genus Procambarus Ortmann

Procambarus Ortmann 1905

Paracambarus Ortmann 1906

Orlmannicus Fowler 1912

Gonopod terminates in three or four

(sometimes two in species ocdirring

outside of Illinois) very short elements.

Ischia of third, or third and fourth,

pereiopods of male with hooks.

Illinois harbors four species of Pro-

cambarus, a genusof 148sije(ies(Hobbs

1981) reaching its greatest diversity in

the southern United States and extend-

ing as far south as Cluba and Honduras.
The lour s|3e( ies in Illinois ari' sluggish-

water inhaljitanis, as are most species

of the genus. Illinois species are in the

subgenera Girardiella (gracilis), Ort-

niinuiicus (aculus and iiian'iridis). and
.S( afj u lit a )n bams (da rk li).



370 Illinois Natural History Survey Bulletin Vol. 33. An. 4

Procambarus gracilis (Bundy)

(Fig. 98)

Catnbarus gracilis Bundy 1876

Description.—Rostrum broad, deejjly

exca\aied. with short acumen, no
median carina; margins barely converge

anteriorly, without tubercles or spines.

Carapace compressed, lacking cervical

spines; suborbital margin angular.

Areola extremely narrow, almost linear.

Chela large, hea\ily punctate; palm
with one row or large tubercles on
mesial maigin; dactyl with shallow

concavity on basal half of opposable

margin. Form I gonopod terminates in

four short elements: a sclerotized, curved

central projection; a curved mesial

process; a straight cephalic process;

Fig. 97.— Bell Pond, east of Grantsburg, Johnson County, Illinois (8 October 1984), supports
large populations of C. puer and P. clarkii.



August 1985 Crayfishes and Shrimps of Illinois 371

Table 6.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and
females carrying young, in Illinois collections of Cambarellus puer.



372 Illinois Natural History Survey Bulletin \'ol. 33. An. 4

I

Fig. 98 —Procambarus gracilis. A, dorsal view of carapace: B, dorsal view of right chela:
C, annulus ventralis: D, mesial view of gonopod of form I male: E. lateral view of gonopod of
form I male: F, lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 373

Fig. 99.—Total distribution of Procambarus
gracilis. Ttie eastern limit of its range is un-
known.

Illinois in February, March, April, and
May. Brown (1955) found form I males

in Illinois in August and October and
females with young attached in March,

April, and October. Brown's largest

form I male was 39 mm CL, and his

largest female was 47 mm CL. Williams
& Leonard (1952) found young attached

to many of the females collected in

early spring in Kansas. Greaser (1932)

Fig, 100.— Distribution of Procambarus
gracilis in Illinois. Open circle = 1922 record

for the Kankakee River; black dots = 1972-1982
collections.

noted that "females with young at-

tached are taken in Missouri as late as

Octobei."

Among all specimens collected in the

present study, males outnumbered

Table 7.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and
females carrying young, in Illinois collections of Procambarus gracilis.



374 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

4

<-:.'k^'

Fig. 101 .—Roadside ditch, % mi. W Winterrowd, Effingham County, Illinois. 3 f^/lay 1977; typi-

cal habitat for Procambarus gracilis.

Fig. 102.—Capped entrance to burrow of

Procambarus gracilis in a field in Des Plaines,

Cook County, Illinois, 15 June 1972.

Males ( Form I)

_i

ca

5 -1

5

rH T
Females

if Vl.n

-
1 nn„^^

5 10 15



August 1985 Crayfishes and Shrimps of Illinois 375

Fig. 104.

—

Procambarus acutus. A, dorsal view of carapace: B, dorsal view of right chela;

C. annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of

form I male; F, lateral view of gonopod of form II male.



376 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Procambarus acutus (Girard)

(Fig. 104)

Cambarus acutus Girard 1852

Cambarus stygius Bundy 1876

Description.—Rostrum broad pos-

teriorly, strongly converges anteriorly,

excavated, no median carina, marginal

spines or tubercles small to absent

(largest on small individuals). Carapace

compressed, cervical spines present;

suborbital margin angular. Areola

narrow, narrowest part about 5-8 per-

cent of length. Chela long and narrow,

heavily piinctate; palm with row of

large tubercles on mesial margin, one

or two adjacent rows on dorsal and

ventral surfaces. Form I gonopod

terminates in four elements, all more

or less directed caudodistally and vari-

ously obscured by a mass of setae origi-

nating on the caudal knob: a relatively

large sclerotized central projection, an

unsclerotized slender mesial process,

a sclerotized cephalic process, and a

sclerotized caudal process. Dorsal color

pinkish brown to dark red; largest in-

dividuals dark red with a black rectangle

on each abdominal segment.

Fig. 105.—Total distribution of Procambarus

acutus.

P. acutus is a member of the P. blan-

dingii species group of the subgenus

Ortmannicus (Hobbs 1962, 1972b). Two
subspecies of P. acutus are recognized.

P. a. cuevachicae occupies San Luis

Potosi and Puebla and intergrades with

P. a. acutus in northern Mexico and

Texas. P. a. acutus occupies the rest

of the range of the species (Hobbs

1972a), as described below. Hobbs ( 1981

)

noted the existence of se\eral regionally

restricted "variants" of P. a. acutus^nd

suggested that some may deserve taxo-

nomic recognition.

Cambarus stygius was described bv

Bundv (in Forbes 1876) from specimens

found, following a storm, on the shore

of Lake Michigan at Racine, Wisconsin.

(Bundv 1882) and listed by Forbes (18/6)

as an Illinois species. Creaser (1932)

declared Cambarus stygius to be a syno^

nym of Cambarus blandmgii acutus (-

Cambarus acutus Girard).

Distribution and Habitat.— P. acutus

has a disjunct range. In the east it occurs

along the Atlantic Slope from Maine

to central Georgia (Altamaha Rner sys-

tem) and to the west (Great Lakes and

Mississippi Ri\er basins) it ranges from

southern Michigan and western Indiana

west to southeastern Minnesota and

south to Alabama, western Oklahoma,

and along the Gulf slope into Mexico

(Fig. 105).

P acutus has been counted among

the Illinois fauna since 1870 (Hagen

1870), and Forbes (1876) stated that it

was very common in ceniral Illinois.

Rietz (1912) found the species (as Cam-

barus blaminigii) to be widely distrib-

uted and generally abundant and docu-

mented its occurrence in ;}2 Illinois

counties. Brown (1955) found it m 36

counties drained by the Sangamon

Wabash, and Ohio river systems and

reported it especiallv common in the

Sangamon system. Populations m Il-

linois were generally referred to as

P blaniiingii until Hobbs (1962) re-

stricted the range of P. a. blanclmgn)

to North and South Carolina.

Presently P. acutus occupies most,

perhaps all, drainages of the state, but



August 1985 Crayfishes and Shrimps of Illinois 377

Fig. 106 —Distribution of Procambarus
acuius in Illinois; black dots = 1972-1982 col-

lections.

records are absent from the Spoon and
other small rivers in western Illinois and
from the Pecatonica and other streams

in northwestern Illinois (Fig. 106). It is

most common in the sluggish streams

of southern Illinois, especially in the

Big Muddy drainage and in streams on
the Coastal Plain. Being a relatively

deep water species, P. acutus is some-

what more difficult to capture than are

shallow water crayfishes, and it may be

more common in Illinois than present

records suggest.

In Illinois, the species is most com-
mon in permanent standing water

bodies, especially those with luxuriant

vegetation, and also is found in stream

pools and slowly flowing runs with

mud or sand bottoms. Elsewhere, the

species occupies similar habitats but

also may rarely be found in swiftly

flowing streams (e.g., Williams 1954;

Brown 1959; Hobbs 1981).

A burrow may be constructed and
inhabited when water bodies reach

below-normal levels (Cralley 1932;

Creaser &: Ortenburger 1933), adults

may burrow during cold weather, and
females sometimes sequester themselves

in burrows when carrying eggs and
young (Cralley 1932; Penn 1956; Hobbs
1981). The sequestering behavior could

explain the extremely small number
of ovigerous females found in Illinois

and elsewhere (see below). In the Reel-

foot Lake area, Hobbs & Maichand
(1943) found burrows of P. acutus to

be shallow excavations, usually under

logs and consisting of a single passage-

way extending only a few inches under-

Table 8.—Frequency of occurrence of form I males, females carrying eggs (ovigerous), and

females carrying young, in Illinois collections of Procambarus acutus.



378 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

ground. A burrow 60 cm deep was found

along the margin of a drainage ditcfi

in Iowa (Phiillips 1980).

Life History.—In the present survey

of Illinois, 212 collections of P. acutus

were made. Form I males were found

every month except October and No-

vember (Table 8). They peaked in rela-

tive abundance in June-September and,

secondarily, in January. Cralley (1932)

found form I males in Illinois in June
and July, and Brown (1955) from April

to July and in September. Form I males

have been found in June and July in

western Tennessee (Hobbs &: Marchand
1943); in August and September in the

Ozark-Quachita region (Williams
1954); from February to July and in

September in Texas (Penn & Hobbs
1958); from May to August in Iowa
(Phillips 1980); in April, August, and
"the fall" in Georgia; in March, April,

June, July, and September in Alabama;
in April and May in Florida; and in all

months except May in South Carolina

(Hobbs 1981).

No females were found carrying eggs,

and only one (49.3 mm CL), collected

in December, was carrying young {N =

30). In other Illinois surveys, Rietz

(1912) reported a female collected with

young in April, Cralley (1932) reported

ovigerous females collected in July,

and Brown (1955) found a female with

eggs in August and one with young
attached in April. All females with

eggs and young found by Cralley and
Brown were taken from burrows.

Few females with eggs or young have
been collected elsewhere, probably
because of their sequestering behavior
(Penn 1956; Hobbs 1981). In\he south-

eastern United States, no females with
eggs and only one female with young
(from Alabama in September) have been
collected (Hobbs 1981). Turner (1926)

reported eggs and young on P. aculus
in Ohio and Indiana in March, July,
and September, and Penn (1956) found
females with young attached in October
and January in Louisiana.

In the present survey males slightly

outnumbered females, 523 to 513. The

largest Illinois specimen is a 54.1-mm
CL female collected on 20 February

1974 in the Maeystown Creek system,

Monroe County. The largest male is a

54.0 mm-CL form I collected in 1974

in the Mississippi River, Whiteside

County. Hobbs (1981) recorded a 58.9-

mm CL form I male from Georgia. The
smallest form I male from Illinois is

30.8 mm CL and was collected in the

Mississippi River, Randolph County,

on 24 March 1975.

Procambarus viaeviridis (Faxon)

(Fig. 107)

Cambarus viae-vnidis Faxon 1914

Description.—Rostrum flat, deflect-

ing downward anteriorly; margins con-

verge anteriorly to short acumen, with-

out spines or tubercles; no median
carina. Carapace compressed, lacking

cervical spines; suborbital margin
barely angular. Areola narrow, narrow-

est part about 4-7 percent of length.

Chela long and narrow, heavily punc-

tate; palm with row of 7-9 long tuber-

cles on mesial margin. 2-3 adjacent

rows of smaller tubercles. Form I gono-

pod terminates in four short elements:

a sclerotized mesial process, a sclero-

tized central projection, a cephalic

process, and a large setae-covered

caudal knob on cephalic surface. Adults

are deep rust red dorsally with the ab-

domen somewhat lighter in color than

the carapace.

P. viaeviridis is a member of the P.

blandingii species group of the sub-

genus Ortmanniciis (Hobbs 1962,

1972b).

Distribution and Habitat.—P. viae-

viridis occupies standing water bodies

and sluggish streams on the former

Mississippi Embayment and Gulf
Coastal Plain from southern Illinois

south to northern Louisiana and cen-

tral Alabama (Fig. 108).

P. viaeviridis is restricted in Illinois

to cypress swamps and floodplains

along sluggish streams in the extreme
southern part of the state (Fig. 109).

First reported for Illinois by Page and
Burr (1973), the species now is known



August 1985 Crayfishes and Shrimps of Illinois 379

Fig. ^07.—Procambarus viaeviridis. A, dorsal view of carapace; B, dorsal view of right chela-
C, annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



380 Illinois Natural History Survey Bulletin

1

Vol. 33, An. 4

Fig. 108.—Total distribution of Procambarus
viaeviridis.

from localities in the Ohio River drain-

age in Alexander, Johnson, Massac,

Pope, and Pulaski counties. The largest

populations are in cypress swamps
{especially Heron Pond-Little Black

Slough and Bell Pond) in Johnson
County.

Life History.—Other than brief

comments on its affinity for sluggish

and standing bodies of water, nothing
appears to have been published on the

ecological characteristics of P. inaeviri-

dis. During the present study, 16 collec-

tions of the species were made, all from
December through May (Table 9).

Fig. 109 —Distribution of Procambarus
viaeviridis in Illinois: black dots = 1972-1982

collections.

During this period, water levels in

southern Illinois are generally high,

and P. I'iaei'iridis can be found on
flooded floodplains, in some roadside

ditches, and in swamps. Periodically

flooded areas appear to be the preferred

habitat of P. I'iacviridis, and when they

dry, (he crayfish burrows underground.

In April, specimens were dug from bur-

rows 15-30 cm deep on the floodplain

Table 9.—Frequency of occurrence of form I males, females carrying eggs (ovigerous). and
females carrying young, in Illinois collections of Procambarus viaeviridis.



August 1985 Crayfishes and Shrimps of Illinois 381

'> ~' "^-^i i^rT'^^^ , i.-* •*<<.• \L.. V ^,H ^, '• S^i.

Fig. 110.—Floodplain of Max Creek at the Route 147 bridge, Johnson County, Illinois, 8
October 1984. Procambarus viaeviridis can be found here above ground during flooding and
can be dug from burrows during periods of low water. P. viaeviridis persists here even though
the formerly forested floodplain now is covered with grasses.

of Max Creek, Johnson County (Fig.

110). In December and January, 1975-

76, crayfish were active in water 1°C
under a cover of ice. The usual absence

of floodwater in southern Illinois from

June through November accounts for

the lack of Illinois collections during
this period (Table 9); howe\er, more
extensive effort presumably would

Males ( = Form I)

mm CL

Fig. 111.—Size-frequency distribution of

Procambarus viaeviridis collected in Bell Pond,
Johnson County, Illinois, 19 May 1973.

reveal that the species may be found in

permanent swamps even during this

period.

Form I males were present in collec-

tions made in January and May (Table

9). Among the four form I males col-

lected, the smallest was 24.1 mm CX,
and the largest was 29.9 mm C^L. I'he

largest Illinois specimen of P. viaeviri-

dis is a 32.3-mm CL female collected in

Heron Pond on 30 March 1973. No
females with eggs or young attached

were collee ted. The smallest indi\ iihials

(about .5-10 mm CL) were collected

in Januaiy and P'ebruary.

riie leiigth-iieciuency distiibution of

indi\iduals (ollected in Bell Pond in

May (N - 50) suggests that the spec ies,

at least in Illinois, lives 2 years (Fig.

111). The sex ratio in this collection

was 1 .1 males: 1 female.

Procambaru.s ciarkii (C»iiard)

(Fig. 112)

Ciimhariis Clarkii Ciiard 1852

Description.— Rostrum dee|)ly ex-



382 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Fig. ^^2.—Procambarus clarkii. A, dorsal view of carapace: B, dorsal view of right chela;
C, annulus ventralis; D, mesial view of gonopod of form I male; E. lateral view of gonopod of
form I male; F. lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 383

cavated; margins converge anteriorly,

terminating in small to large spines;

acumen long; no median carina. Cara-

pace compressed, with cervical spines;

suborbital margin angular. Areola ex-

tremely narrow, sometimes obliterated

at midlength. Chela long and narrow,

punctate; palm with row of 6-8 tu-

bercles on mesial margin, 2-3 adjacent

rows of smaller tubercles. Form I gono-
pod with a large angular shoulder on
cephalic surface, a large lobiform scle-

rotized cephalic process, small mesial

process, and small sclerotized central

projection. Light to dark red dorsally

and laterally; white ventrally with blue

stripe along middle of abdomen.
P. clarkii is a member of the subgenus

ScapuUcarnbarus (Hobbs 1972b), an
assemblage of six species confined to

the Atlantic and Gulf Coastal Plain of

the United States and Mexico (Hobbs
& Grubbs 1982).

Distribution and Habitat.—P. clarkii

is an abundant inhabitant of standing

water bodies and slowly flowing streams

on the Gulf Coastal Plain from the

Florida panhandle to northern Mexico
and up the former Mississippi Embay-
ment to southern Illinois (Fig. 113). It

is the crayfish commonly harvested for

human consumption in the eastern

United States.

In Illinois, P. clarkii occurs in

swamps, vegetated ponds, and stream

pools in the extreme southern part of

the state (Pope, Johnson, Massac,

Union, Pulaski, and Alexander coun-
ties) (Fig. 114). Most localities are in

the Ohio River drainage, although
some are in the Mississippi River drain-

age. It remains common, especially in

Mermel Swamp (Fig. 89), Bell Pond
(Fig. 97), LaRue Swamp, Horseshoe
Lake, and parts of the Cache River sys-

tem but undoubtedly was more com-
mon prior to the drainage of much of

the southern Illinois wetlands. P. clarkii

is taken often with P. acutus but is more
common than P. acutus in the cypress-

Fig. 113.—Total distribution of Procambarus
clarkii. The southwestern limit of its range is

unknown.

Fig. 1 14.— Distribution of Procambarus clar-

kii in Illinois; black dots = 1972-1982 collec-

tions.



384 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Table 10.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Procambarus clarkii.



August 1985 Crayfishes and Shrimps of Illinois 385

Fig. 116.

—

Orconectes illinoiensis. A, dorsal view of carapace; B, dorsal view of right chela;

C, annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of

form I male; F, lateral view of gonopod of form II male.



386 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

found two females witfi eggs and three

with young attached in Illinois on 6

September 1954; all were dug from bur-

rows. Penn (1943) found a female only

30.5 mm CL carrying young in Loui-

siana.

The largest Illinois specimen is a

60.7-mm CL female collected in Horse-

shoe Lake, Alexander County, on 20

June 1973; the largest male, from the

same collection, is a 51.7 inm CL
form I. Brown (1955) recorded a 54-

mm CL form I male from Illinois.

The size-frequency distribution of 116

individuals collected in the Bay Creek

system on 19 May 1973 suggests that

individuals of both sexes live a maxi-

mum of about 2 years (Fig. 115), al-

though the largest female mentioned

above, at 60.7 mm, may have been 3

years old.

Genus Orconectes Cope

Orconectes Cope 1872

Faxonius Ortmann 1905

Gonopod with two terminal ele-

ments; central projection not large

and bladelike. Ischium of third pereio-

pod with hook.

Ten of the 65 recognized species of

Orconectes (Hobbs 1981) occur in Il-

linois. Species of Orconectes are, with

few exceptions, open stream inhabitants

and they, more than other crayfishes,

have foimd Illinois suitable for oc-

cupation.

Orconectes illinoiensis Brown
(Fig. 116)

Orconectes illinoiensis Brown 1956

Description.—Rostrum deeply exca-

vated, deflecting downward anterior-

ly; long acumen; margins thick, con-

verging anteriorly, straight to slightly

concave, terminating in spines; no
median carina. Carapace flattened

dorsoventrally, with large cervical

spines; suborbital margin smooth to

slightly angular. Areola moderately

wide, narrowest part about 13-15 per-

cent of length. Chelae large, heavily

punctate; fingers often very long; palm

with row of 8-9 tubercles on mesial

margin; 1-2 adjacent rows of tubercles

on dorsal surface. Form I gonopod ter-

minates in two short, straight elements:

a sclerotized central projection and an

unsclerotized mesial process. Dorsally

light to dull red brown; fingers of chelae

with red tips, subdistal black bands.

O. illinoiensis is a member of the

Propinquus group of Orconectes (Fitz-

patrick 1967). The closest relative in

Illinois is O. propinquus.

Distribution and Habitat.

—

O. il-

linoiensis is endemic to southern Il-

linois. It was recognized first by Brown
(1955) as a distinct species and formally

described by him in 1956. During the

present survey it was found to occupy

rocky riffles and pools of streams in the

Ohio and Big Muddy (Mississippi River

drainage) systems of Hardin, Pope.

Johnson, Massac, Pulaski, Alexander.

Union, Williamson, and Jackson
counties (Fig. 117). Most of the known

Fig. 117— Distribution of Orconectes illi-

noiensis: blacl< dots = 1972-1982 collections.



August 1985 Crayfishes and Shrimps of Illinois 387

localities (Fig. 118) are in the Shawnee
Hills, but a few populations occupy
rocky streams on the Coastal Plain and
in the region just north of the Shawnee
Hills. Some populations may have been

eliminated or reduced in recent decades

through stream desiccation or other

recent perturbations, but the distribu-

tion of the species today probably ap-

proximates its prehistoric distributicjn.

Many populations are large, especially

in upland streams in Pope County.

Brown (1956) recorded a collection

of O. illinoiensis from Cypress Ditch

near Junction in Gallatin County. This

is in the Saline River drainage, from

Fig. 118 —Gibbons Creel*, Herod, Pope County, Illinois, (8 October 1984) provides habitat

for Orconecles illinoiensis.



388 Illinois Nati'ral History Sirve^- Billetin \'f)l. 33, An. 4

Table 11.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Orconectes illinolensis.



August 1985 Crayfishes and Shrimps of Illinois

r Ji?V^°~?'?°"l'"®^
immunis. A, dorsal view of carapace: B. dorsal view of right chela-

rormTma eT LtPr«, ""'f
"'" °' ^°"°P°' °' '"^"^

' "^^'^^ ^' '^'«-' -«- °' gonop'od ojlortn 1 male. F, lateral view of gonopod of form II male.



390 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Fig. 121.

immunis.

-Total distribution of Orconectes

spines; suborbital margin bluntly an-

gular. Areola narrow, constricted an-

teriorly, narrowest part about 10 percent

of length. Chelae moderate in size,

heavily punctate; palm with 2-3 rows
of small tubercles on dorsomesial mar-
gin. Form I gonopod terminates in two
fairly short (central projection about
23 percent of total length of gonopod)
elements curved at 90° angle to main
axis: a sclerotized central projection

and an unsclerotized mesial process.

Annulus ventralis distinctive, with fos-

sa far to one side. Dorsal color highly
variable, from uniformly red brown to

light green with dark brown mottling;

fingers of chelae without bright red

tips and subdistal black bands.

O. immunis is a member of the J'irilis

group of Orconectes and is most similar

to O. alabamensis, O. rhoadesi, and
O. validits. spec ies inhabiting the Caim-
berland, Tennessee, and Mobile Bay
drainages. Some populations of the

wide-ranging O. immunis have been
considered sufficiently distinct to war-
rant laxonomic recognition (see syn-

onymy abo\e), and Bovbjerg (1952)

referred to northeastern Illinois popu-
lations as "O. immunis x pedianus."

However, Williams &: Leonard (1952)

found that the characteristics which
had been used to distinguish subspecies

varied clinally and could not be used to

diagnose geographically limited popu-
lations. No subspecies were recognized

by Hobbs (1974b).

Distribution and Habitat.

—

O. im-

munis ranges from southern Quebec,
Maine, and Connecticut west through
the Great Lakes (except Lake Superior),

to eastern Wyoming and eastern Col-

orado (Fig. 121). The southern edge

of the range approximates the southern

limit of Pleistocene glaciation but

extends farther south into western Ken-

tucky and Tennessee and farther west

into the Great Plains. An isolated pop-
ulation in Muddy Creek (Canadian-

Arkansas River drainage), Okfuskee

Fig. 122.— Distribution of Orconectes im-

munis In Illinois; black dots = 1972-1982 col-

lections.



August 1985 Crayfishes and Shrimps of Illinois 391

%

^^

Fig. 123— Little Wabash
River, 2 mi. WSW Mattoon,
Coles County, Illinois, 25
October 1983. This and
other sluggish weedy
streams in Illinois often

contain large populations

of Orconectes immunis.

County, Oklahoma, (Creaser &: Orten-

burger 1933) is far south of other popu-
lations and may have been introducted.

The species occurs throughout Illi-

nois except in the unglaciated north-

west (Fig. 122). It appears to be rare

in extreme western Illinois, although

Rietz (1912) found it in several western

counties (Fulton, Hancock, Henderson,

and Mercer) for which recent records are

unavailable. Elsewhere in the state it is

generally common, and local popula-

tions sometimes consist of thousands

of individuals. It undoubtedly was even

more common and widespread when
Illinois had large expanses of undrained

prairies. In fact, Forbes (1876) referred

to O. immunis as "the commonest
species of central Illinois," and "es-

pecially frequent in the muddy ponds of

the prairies, where it may be drawn by

the hundreds with a small seine."

O. immunis lives in slowly flowing

pools, usually with soft bottoms, of

headwaters, creeks, and srnall to large

rivers (Fig. 123). It also is found in

standing-water bodies but, at least in

Illinois (and in the Reelfoot Lake region

of Tennessee, Hobbs & Marchand 1943),

is primarily a stream species. It fre-

quents intermittent streams and tem-

porary ponds, burrowing down to the

water table as drying occurs. O. im-

munis can be found under rocks in dry-

ing streams, and burrows are con-

structed as a means of escaping des-

iccation. Burrows usually are simple

structures, although they may have
chimneys and occasionally are relatively

elaborate. Brown (1955) described the

burrows as up to 2 feet deep and ending
in an enlarged pocket below the water

table.

Tack ( 1 94 1 ) made observations on the



392 Illinois Natural History Sirvev Bi lletin \ol. 33. An. i

Table 12.—Frequency of occurrence of form I males, females carrying eggs (ovigerous).

and females carrying young, in Illinois collections of Orconectes immunis.



August 1985 Crayfishes and Shrimps of Illinois

Fig. 124.— Orconecres indianensis. A, dorsal view of carapace; B, dorsal view of rigfit cfiela;
C, annulus ventralis; D, mesial view of gonopod of form I male: E. lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



394 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

total length (about 20 mm CL) (Rietz

1912).

Females carry eggs in Illinois from

January through April and carry young
from April through June (Rietz 1912;

Brown 1955; Table 12). The smallest

ovigerous Illinois female is 22 mm CL
(collected in Richland County, 12 April

1979), the same length as that reported

by Tack (1941) in New York.

Elsewhere, eggs have been noted in

April and November in Michigan (Her-

rick 1896; Pearse 1910); April, May,
and October in Iowa (Caldwell & Bovb-
jerg 1969; Phillips 1980); March and
April in Indiana (Williamson 1907);

April in Kansas (Harris 1902); April

and October in Nebraska (Engle 1926);

June in North Dakota (Creaser &: Orten-

burger 1933); and October-November
and April-May in New York (Tack
1941; Crocker 1957). Young are carried

in May in New York and Ontario (Tack
1941; Crocker 1957; Crocker &Barr 1968)

and from April through June in Iowa
(Caldwell Xc Bovbjeig 1969; Phillips

1980).

Seven Illinois females collected dur-

ing the present study (21.8-35.9 mm
CL) were carrying 102-285 (mean,

168.9)eggs. Eggs averaged about 1.7mm
in diameter. Three females (26.6-35.5

mm CL) carried 58-184 (mean, 120.3)

young.

The largest individual encountered
during the present survey was a 41.9-

mm CL form II male collected in Ben-
nett Creek, Crawford County, on 30
April 1973. Brown (1955) collected a

46-mm CL female from Illinois, and
Crocker (1957) recorded a 49-inm CL
female from New York. The ratio

among all Illinois specimens collected

was 505 males: 513 females.

Orconectes indianensis (Hay)
(Fig. 124)

Cainbarns itidianensis Hay 1896
Description.— Rostrum exca\ated,

slightly deflet ted downward anteriorly,

with long acumen: margins con\erge
slightly anteriorly, ending in small

Fig. 125.—Total distribution of Orconectes
indianensis.

spines; small median carina. Carapace
flattened dorsoventrally. with large

cervical spines: suborbital margin
barely angular. Areola moderately
wide, narrowest part 15-20 percent of

length. Chela large, hea\ily punctate;

palm with row of 7-9 tubercles on
mesial margin. 2-3 adjacent rows of

smaller tubercles on dorsal surface.

Form I gonopod terminates in two
short, distally tapering and strongly

di\erging elements: a sclerotized cen-

tral projection and an imsclerotized

mesial process. Overall dark brown
dorsally, except thorax yellow brown;
fingers of chelae with red tips and sub-

distal black bands.

O. indianensis is most similar, and
perhaps most closely related, to O.
wrighli. a species known only from
Hardin Countv, Tennessee (Hobbs
1974b).

Distribution and Habitat.—O. in-

dianensis lives in rocky riffles and pools

of small to medium-sized streams in the

Wabash Ri\er drainage of southwestern

Indiana and in the .Saline Ri\er and
Honey Creek systems (both tributary to



August 1985 Crayfishes and Shrimps of Illinois 395

the Ohio River) in southeastern Illinois

(Fig. 125). This species uses stones as

cover and often constructs a short tunnel

with a terminal pocket under a stone as

a resting place (Brown 1955).

Recent Illinois collections of O. in-

dianensis are available from the Saline

drainage of Gallatin, Saline, William-
son, Pope, and Johnson counties, and
from Honey Creek in Hardin County
(Fig. 126). Most collections in the Saline

system are from that part of the system

draining the Shawnee Hills. The north-

ern part of the system, draining the

Mount Vernon Hill Country (Central

Lowland Province) seems to be devoid
of O. iudtanensis. Honey Creek, also in

the Shawnee Hills, is the first large

stream south of the Saline River.

Brown (1955) documented essentially

the same distribution in Illinois as did

the present survey, but his record for O.

illinoiensis in Cypress Ditch, near

Junction, Gallatin County was prob-
ably based on O. indianensis. Rietz

(1912) had more widespread records, but

some of them probably (because of the

localities) were based on misidentifica-

tions of the then undescribed O. illi-

noiensis and O. stanndardi. Rietz's

record for Grand Pierre Creek, Pope
County, and two records for Bay Creek,

Pope and Johnson counties were surely

based on O. illinoiensis. Her record

for Skillet Fork, Wayne County, was
probably based on O. stannardi. The
Little Fox River, White County, record

may have been based on O. propinquus.
However, her records for South Fork

Fig. 126.—Distribution of Orconectes indi-

anensis in Illinois. Open circles = pre-1912

records (Rietz 1912); black dots = 1972-1982
collections.

Saline River and, more interestingly,

for the North Fork Saline River must
have been for O. indianensis. No simi-

lar species occurs or ever has been re-

corded for the Saline system. The North
Fork records are interesting because

O. indianensis no longer is found there.

The North and Middle forks of the

Table 13.—Frequency of occurrence of form I males, females carrying eggs (ovigerous).

and females carrying young, in Illinois collections of Orconectes indianensis.



396 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

I^
Males Form I)

„

[0 Femal es ( with eggs)

10 20 30

mm CL

40

Fig. 127.—Size-frequency distribution of

Orconectes indianensis collected in Honey
Creek, Hardin County, on 23 Marcfi 1973.

.Saline are badly polluted. They suffer

from strip-mine and oil-field pollution,

siltation, and desiccation (Smith 1971)

and are among the most damaged and
abused streams in Illinois. In many
areas of these streams little aquatic life

of any kind can be found.

Life History.—Apparently the only

ecological information on O. indianen-

sis is that presented by Brown (1955) and
that from the present survey.

Brown (1955) found no ovigerous

females and collected form I males only

in September and November. In the

present study, collections were made
from March through October (except

June), and form I males were present

in March, August, September, and
October (Table 13). The smallest form

I male was 17.7 mm CL, and the largest

was 33.4 mm CL.
Ovigerous females were found in

March and April (Table 13). One hun-
dred twenty-one eggs were counted

on a 26.3-mm CL female, 148 eggs on a

27.7-mm CL female, and 178 eggs on a

32.2-mm CL female. Eggs averaged

about 1.8 mm in diameter. The only

female with young attached was 35.0

mm CL and was collected on 19 May
1973. Attached to her were 132 young
and 21 unhatched eggs.

The largest Illinois specimens ex-

amined were the above-mentioned 35.0-

mm female and 33.4-mm form I male.

The size-frequency distribution of 51

specimens collected in Honey Creek.

Hardin County, on 23 March 1973 (Fig.

127) suggests a 2-year life span, with 1-

year-old males averaging 15.2 mm
(N = 25), 1 -year-old females averaging

13.4mm(N = 22),and2-year-olds(.V = 4)

ranging from 25 to 33 mm CL. Of the

219 specimens of O. indianensis col-

lected during the present survey, 104

were males and 115 were females.

Orconectes kentuckiensis Rhoades
(Fig. 128)

Orconectes kentuckiensis Rhoades 1944

Description.—Rostrum excavated,

deflected downward anteriorly, with

long acumen; margins barely converge

anteriorly, ending in tubercles or small

spines; lacks median carina. Carapace

flattened dorsoventrally, with large

cervical spines; suborbital margin
barely angular. Areola wide, narrowest

part about 18 percent of length. Chela

large, hea\ily punctate; palm with row
of 7-9 tubercles on mesial margin; 1-2

adjacent rows of smaller tubercles on
dorsal surface. Form I gonopod termi-

nates in a short, thick, distally directed,

sclerotized central projection, and a

short, caudodistally directed, unsclero-

tized mesial process. Dorsally dark

brown (with yellow brown thorax) to

red brown; fingers of chelae with red

tips, subdistal black bands.

The gonopod of O. kentuckiensis

most closely resembles that of O. sloanii

in southern Indiana and Ohio and O.

hamsonii in southeastern Missouri.

Although the relationships of these

species ha\e not been in\estigated.

O. sloanii and O. harrisonii probably

are the closest relatives of O. kentuck-

iensis.

Distribution and Habitat.

—

O. ken-

tuckiensis occurs only in small streams

in a small area of southeastern Illinois

and northwestern (Crittenden. Li\ing-

ston, and I'nion counties) Kentucky

(Fig. 129). In Illinois, it occurs only

in Big, Hosick, and Peters creeks, three

spring-fed, rocky, direct tributaries of

the Ohio River in Hardin County (Fig.

130). Its distribution in the headwaters

of Big Creek (Fig. 131 ). by far the largest

of the three streams, complements the

downstream distributit)n of O. plandus

I



August 1985 Crayfishes and Shrimps of Illinois 397

Fig^ ^28.-Orconectes kentuckiensis. A, dorsal view of carapace: B, dorsal view of rioht
chela; C annulus ventralls; D. mesial view of gonopod of form I male: E, lateral view of gonopod
ot form I male, F, lateral view of gonopod of form II male.



398 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Fig. 129.—Total distribution of Orconectes
kentuckiensis.

(Boyd & Page 1978). No record of its

occurrence in Illinois predates those of

Brown (1955). O. kentuckiensis prob-

ably was never more widespread in Il-

linois than it is today.

O. kentuckiensis is most common in

shallow, rocky pools of small streams

(Boyd & Page 1978), where large rocks

are used as cover, although Rhoades
(1944a) collected specimens in accumu-

Fig. 130.— Distribution of Orconectes ken-

tuckiensis in Illinois; black dots = 1972-1982
collections.

lations of brush over mud. This species

does not burrow but may bury itself in

loose gravel 2-4 cm below the surface

of a dry stream bed (Boyd k Page 1978).

Life History.—The life history of O.

i

{
Table 14.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Orconectes kentuckiensis.



Fig. 131—Headwaters of Big Creek, 2 mi E Karbers Ridge, Hardin County, Illinois, support

large populations of Orconectes kentuckiensis.



400 Illinois Natural History Survey Bulletin \'ol. 33, Art. 4

kentuckiensis in Big Creek was studied

by Boyd & Page (1978). The species

was active at temperatures of 6°-32°C

and dissolved oxygen levels of 3.5-14.4

ppm. Most individuals were found in

water 5-61 cm deep. The species lived

a maximum of 2+ years, had a 1:1 sex

ratio, fed on vascular plants and arth-

ropods (amphipods, isopods, crayfishes,

caddisflies, and midges), and was preyed

upon by fishes.

Form I males (15.9-37.5 mm CL) were

present from July through April and
peaked in occurrence in November,

December, and February; females carry-

ing eggs or young were present in

March, April, May, and July (Table 14)

and measured 14.8-32.8 mm CL. Fif-

teen females were carrying 49-248

(mean, 110) eggs. Eggs were spherical

and averaged 1.9 mm in diameter. The
relationship between the number of

eggs (N) and the female's weight in

grams (W) was N = 49.809 + 25.310 VV,

r = 0.807, and that between N and the

female's carapace length (L) was N =

-0.43611 + 1.8516 log L, r = 0.859.

Counts of ovarian eggs in 15 females

were 59-249 and averaged 109. Nimi-

bers of eggs, ovarian and abdominal,

increased significantly with carapace

length. The growth of first-year cray-

fish occurred during a period of 4.5

months, of adult males during spring

and summer molts, and of adult females

during a summer molt.

The largest O. kentuckiensis from

Illinois is a 37.5-mm CL form I male

collected on 25 April 1975; the largest

female is 36.2 mm CL, collected on 30

September 1975. Both are from Big

Creek.

Orconectes lancifer (Hagen)
(Fig. 132)

Cambarus lancifer Hagen 1870

Cambariis faxonii Meek 1894

Description.—Rostrum deeply ex-

cavated; acumen longer than basal mar-

gin of rostrum, turning upward ante-

riorly; no median carina; margins con-

vex, diverging anteriorly, terminating

in spines. Carapace slightly flattened

dorsoventrally, with large cervical

spines; suborbital margin angular.

Areola narrow, obliterated anteriorly.

Chela long and narrow, setose, without

tubercles. Form I gonopod terminates

in two short, spatulate elements: a

sclerotized central projection and an
unsclerotized mesial process. Mottled

overall in shades of red, brown, and
green; fingers of chelae without bright

red tips and without black bands sub-

distally.

O. lancifer is a highly distinctive

crayfish with no obviously close rela-

tives.

Distribution and Habitat.—O. lan-

cifer is an inhabitant of the Gulf Coastal

Plain and is known to occur in Louisi-

ana, Mississippi, Tennessee, eastern

Texas, Arkansas, and extreme southern

Illinois (Fig. 133). It lives in deep water

of oxbows, bayous, and large streams

(Black 1972) and, as a result is rather

poorly represented in collections.

O. lancifer has been found at only

two localities in Illinois. Robert Kenni-

cott, an early naturalist, collected a

female at Cairo in the middle 1800's

(Faxon 1914). and Page & Burr (1973)

recorded a collection of eight individ-

uals from Horseshoe Lake. Both local-

ities are in the Mississippi River diain-

age of Alexander County (Fig. 134).

Four additional collections of O. lan-

cifer recently have been made at Horse-

shoe Lake, where the species probab-

ly is common but difficult to collect.

Horseshoe Lake (Fig. 135) is an old.

relatively deep oxbow of the Missis-

sippi River supporting stands of bald

cypress and man> species of Coastal

Plain animals that are rare in Illinois

(E\ers &: Page 1977). Few oxbows of the

Mississippi River exist in southern

Illinois, and O. lancifer is unlikely to

be found elsewhere in the state. Wolf

Lake in Lnion County appears to offer

suitable habitat for O. lancifer. but

several searches there ha\e failed to

document its presence.

In Louisiana. O. /fl;« //cr li\es in deep

(more than 40 cm), clear, permanent



August 1985 Crayfishes and Shrimps of Illinois

r J'9,
^32.-Orconecfes lancifer. A, dorsal view of carapace; B. dorsal view of riaht chela-

?'lTl'itT\Z':;,°'. ---' -«- °' 9-opod of form I male; E. lateral v": o gonopod oflateral view of gonopod of form II male.
form I male; F,



402 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

Fig. 133.—Total distribution of Orconectes
lancifer.

Fig. 134.— Distribution of Orconectes lanci-

fer in Illinois. Open circle = collection made in

the mid-1800's (Faxon 1914); black dots = 1972-

1982 collections.

*/:.

W^^

-»% -^

Fig. 135 —Horsestioe Lake in Alexander County is the only known locality In Illinois still

supporting a population of Orconectes lancifer.



August 1985 Crayfishes and Shrimps of Illinois 403

Fig. 136.

—

Orconectes placidus. A, dorsal view of carapace; B
C, annulus ventralis; D, mesial view of gonopod of form I male; E
form I male; F, lateral view of gonopod of form II male.

dorsal view of right chela;

lateral view of gonopod of



404 Illinois Natural History Slirvey Bulletin Vol.33. Art. 4

water over mud or mixed mud and sand

with little aquatic vegetation present

(Penn 1952). This description fits

Horseshoe Lake fairly well except that

the lake is heavily vegetated.

Life History.—Black (1972) sum-

marized the scant life history data avail-

able on O. lancifer: form I males have

been collected from August through

November; females carrying eggs or

young have been found only in Feb-

ruary; juveniles predominate in May,

June, and July.

Among the collections made in Il-

linois are two made in June and one

each in July, September, and October.

The September and October collections

contain a total of three form I males

(30-32 mm CL). Also in the Illinois

Natural History Survey collection is a

40-mm female from Cheniere Lake,

Ouachita Parish, Louisiana, collected

on 18 February 1977, with 570 eggs

attached. The eggs average 1.5 mm in

diameter. These additional observations

agree with Black's (1972) description

of an autumnal breeding season and
winter egg-laying season.

Orconectes placidus (Hagen)
(Fig. 136)

Cainbarus placidus Hagen 1870

Description.—Rostrum excavated,

no (or low) median carina, long acu-

men; margins thick, straight to slightly

concave, barely converging anteriorly,

terminating in spines. Carapace flat-

tened dorsoventrally, with large cervical

spines; suborbital margin smooth.
Areola moderate, narrowest part about
11-15 percent of length. Chelae large,

heavily punctate; palm with 2-3 rows
of tubercles along mesial margin. Form
I gonopod terminates in a long sdero-

tized central projection curved at tip and
a slightly shorter unsclerotizcd mesial

process; cephalic surface smooth or with
broadly rounded (not angular) shoul-

der. Dorsal ly red brown; fingers of

chelae with red tips, subdistal black

bands.

Fig. 137—Total distribution of Orconectes
placidus.

Fig. 138.— Distribution of Orconectes placi-

dus in Illinois; black dots = 1972-1982 col-

lections.



August 1985 Crayfishes and Shrimps of Illinois 405

Fig. 139.— Gravel riffles in the lower portion of Big Creel<, Hardin County, Illinois (10 March
1976) provide the best habitat in Illinois for Orconectes placidus.

Among the crayfishes of Illinois,

populations herein assigned to O.

placidus arc the most troublesome tax-

onomically. The only large population

is that in Big Creek in Hardin County;

other populations are small, highly

localized ones inhabiting rocky areas

along the banks of the Ohio and Missis-

sippi rivers. Although all are assigned

to O. placidus, these populations show
variations usually indicative of specific

distinctiveness in Orconectes. The
gonopod of the form I male lacks any

hint of a shoulder on its dorsal surface

in Big Creek specimens but has a defi-

nite shoulder (although not as pro-

nounced and angular as in O. rusticus)

in Mississipi^i Ri\er specimens (no form
I males from the Ohio River are avail-

able). Big Creek specimens always lack

a carina on the rostrum; those from the

Ohio and Mississippi rivers may or may
not have one. In general, western j)op-

ulations differ the most from typical

O. placidus occupying the Cumberland
and Tennessee river systems in Ken-

tucky and Tennessee (Hobbs 1971b).

Variation in O. placidus and its rela-

tives is badly in need of study.

Distribution and Habitat.— O. placi-

dus occupies streams of the Cumber-
land, Tennessee, and lower Ohio rivers

in Kentucky, Tennessee, and Illinois

(Fig. 137). It lives in rocky riffles and
pools, using cavities and interstices as

hiding places.

Recent Illinois records exist for Big
Creek, Hardin County, the Ohio River,

Massac and Pulaski counties, and the

Mississippi River, Randolph and Jack-
son counties (Fig. 138). Most of the

large-river collections were made along
rocky banks or in rocky backwater areas.

In the Big Creek system, O. placidus is

found mainly in downstream gravel

and rubble riffles (Fig. 139), and O.
kentuckiensis is found mainly in up-
stream shallow rocky pools (Boyd &:

Page 1978). As discussed below for O.
rusticus, Hagen's (1870) and P'orbes'

(1876) reference to "C. placidus" at

Quincy is thought to refer to a waif of

the Missouri po{)ulalions of O. ( f . rusti-

cus. Brown's (1955) discussion of "O.



406 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Table 15.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Orconectes placidus.

Numbfr and Percent of Colleclions with

Month
Number of

Collections Fovm I Males Ovigerous Females Females with Young

I

January

February

March
April

May
June
July

August
September

October

November
December

3

1

6

2

6

19

3

1

7

8

4

1

67

83

71

88

75

100

17

50

<:

a
1 r^MJu :;:

es ( = Form I)

5 10

" 5

o
^

Females

10

1 ^
.

n n

20 30
mm CL

40

Fig. 140.—Size-frequency distribution of

Orconectes placidus collected in October in

Big Creek, Hardin County.

rusticus" refers to the Big Creek popu-
lation of O. placidus.

Life History.—During the life-

history study of O. kentuckiensis {Boyd
& Page 1978), a large number (61) of

collections of O. placidus were made.
The following observations are based

on those collections.

Form I males were present in collec-

tions from September through January
and in March (only one collection was
made in February) (Table 15). Brown
(1955) found form I males in Big Creek
in November.
Ovigerous females (N = 'i) were found

only in March and April (Table 15);

they were 15.7, 20.5, and 27.2 mm CL,
with 12, 88, and 134 eggs attached,

respectively. Eggs were spherical and
averaged 2.1 mm in diameter. No fe-

males with young attached were found.

The largest pieser\ed Illinois male is

a 45.6-mm form II; the largest female

is 41.7 mm CL. Both were collected in

May and, compared with the size-fre-

quency distribution of October-col-

lected specimens (the largest sample),

were probably 2 or 3 yearsold(Fig. 140).

The largest form I male (39.6 mm) has

extremely large chelae (right chela =

4(>. 1 mm long). Among the Big Creek
specimens were 344 males and 387 fe-

males (a ratio of 1:1.13).

Among a combined total of 506 stripe-

tail and spottail darters {Etheosloma

kennicotti and E. squainiceps) exam-
ined, the ingested remains of crayfishes

were found in the stomachs of 4 E.

squainiceps (Page 1974a, 1975). Con-
sidering the relative abundances of cray-

fishes in Big Creek, these were almost

certainly O. placidus or O. kentuckien-

sis (Boyd & Page 1978).

Orconectes propinquus (Girard)

(Fig. 141)

Carnbarus pwpitiquus Girard 1852

Orconectes iowaensis Fitzpatrick 1968

Description.— Rostrum exca\ atcd.

deflecting downward anteriorly; well-

developed median carina; long acumen;
margins thick, straight or slightly con-

tavc, barely coinerging anteriorly, ter-

minating in spines or lagc tubercles.

Carapace flattened doisoventrally, with



August 1985 Crayfishes and Shrimps of Illinois 407

Fig. 141.—Orconecfes propinquus. A, dorsal view of carapace; B, dorsal view of right chela:
C, annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



408 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

cervical spines; suborbital margin
smooth. Areola wide, narrowest part

about 19-25 percent of length. Chelae

large, heavily punctate; palm with 2-3

rows of tubercles on mesial margin.

Form I gonopod terminates in two
short, straight elements: a sclerotized

central projection and an unsclerotized

mesial process. Dorsal ly green to red

brown; fingers of chelae with red tips,

subdistal black bands.

Fitzpatrick (1967) found O. propin-

cjiius to be the most variable species

among the Propinquus group of spe-

cies but also to lack taxonomically

recognizable subspecies. "O. wmaen-
sis," previously thought to be a para-

patric relative of O. propinquus oc-

cupying areas of Iowa adjacent to Il-

linois (Fitzpatrick 1968), has been rele-

gated to the synonymy of O. propin-

quus by Page (1985).

Distribution and Habitat.—O. pro-

pinquus ranges from southern Ontario

and Quebec south to Illinois, Indiana,

Ohio, northern Pennsylvania, New
York, and Massachusetts. To the west,

its range extends into eastern Iowa and
southeastern Minnesota (Fig. 142).

In Illinois, O. propinquus occurs in

Lake Michigan and in the Wabash. Il-

linois, Rock, Mississippi, and extreme

upper Kaskaskia drainages (Fig. 143).

In the Wabash drainage, it extends as

far south as White County, is wide-

spread in the Embarras River, but is

absent in the Little Wabash River sys-

tem. In the Illinois and Mississippi

rivers, it occurs as far south as Calhoun
and Rock Island counties, respectively.

Throughout its range in Illinois,

O. propinquus is the most common
crayfish in clean rocky riffles (Fig. 144).

In the fast, rubble and gravel riffles

characteristic of the Vermilion, Kan-

kakee, and upjH'r Rock drainagis, O.

propinquus often is abundant. Its ab-

sence in most of western and central

Illinois presumably is due to the ab-

sence of suitable habitat; its absence

in southern Illinois apparently is due lo

the presence there of t)lher species of

Fig. 142.—Total distribution of Orconectes
propinquus. The northeastern limit of its range

is unknown.

Fig. 143.— Distribution of Orconectes pro-

pinquus in Illinois: black dots = 1972-1982.



August 1985 Crayfishes and Shrimps of Illinois 409

Fig. 144.—Middle Fork Vermilion River, near Collison, Vermilion County, Illinois, provides

abundant habitat for Orconectes propinquus.

rocky stream-inhabiting species of

Orconectes.

O. proptuquus may dig under stones

on the stream bed to escape desiccation

(Bovbjerg 1952; Brown 1955) or occa-

sionally into stream banks (Hay 1896;

Cralley 1932). Young often are found
in vegetation along the margins of a

stream. Altliough primarily an inhabi-

tant of rocky streams, it can become
established in lakes (Bovbjerg 1952).

O. propinquus remains u'idespiead

and locally common, even abundant,
in some areas but probably was more
widespread and common prior lo the

extensive modification of the Illinois

landscape. It does best in clean, clear

streams and presumably has suffered

population declines as stream siltation

has progressed during tfie last few dec-

ades. Among the widespread crayfishes

of Illinois, it is probably the best in-

dicator of environmentally healthy

streams.

All earlier records of O. propinquus
in Illinois fall within, or almost within,

the present distribution. The record lor

the Kaskaskia drainage, near Hum-
boldt, Coles County (Rietz 1912), is one

county to the south of recent records.

This record is signifitani in document-

ing tlie fact tliat the presence ol the



410 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

Table 16.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Orconectes propinquus.



August 1985 Cravfishk and Shrimps of Iixih 411

Fig. 145—Orconecfes rusticus. A, dorsal view of carapace; B, dorsal view of right chela;
C. annulus ventralis; D. mesial view of gonopod of form I male; E, lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



412 Illinois Natural History Survey Bulletin Vol. 33, An. 4

and May in Iowa (as O. iowaensis,

Phillips 1980), and eggs and young
in April-June in Michigan (Pearse

1910; Creaser 1931). Females with eggs

and young may be as small as 16 mm CL
(Crocker 1957; Berrill 1978). Eggs are

spherical and average about 1.9 mm in

diameter.

The ratio of males to females among
recent Illinois collections is 334:335.

The largest specimen collected during

the present survey is a 39.3-mm CL
female; the largest male is a 31.5-mm
form I. Van Deventer (1937) and Brown
(1955) each recorded a 40-mm male;

Cralley (1932) recorded a 90-mm TL
(about 45-mm CL) male and a 90-mm
TL female from Champaign County.

O. propinquus is omnivorous, feed-

ing on plant materials and insect larvae

(Bovbjerg 1952).

Orconectes rusticus (Girard)

(Fig. 145)

Cambarus rusticus Girard 1852

Cambarus juvenilis Hagen 1870

Description.—Rostrum excavated; no
median carina; long acumen; margins
thick, concave, terminating in spines.

Carapace flattened dorsoventrally, with

cervical spines; suborbital margin
smooth. Areola moderate, narrowest

part about 10-15 percent of length.

Chelae large, heavily punctate; palm
with two rows of tubercles on mesial

margin. Form I gonopod with an an-

gular (90° to axis of gonopod) shoulder

on dorsal surface, terminating in two
long elements: a sclerotized central

projection curved at its tip, and a slight-

ly shorter unsclerotized mesial process.

Dorsally green brown to rust red; often

a large red spot surrounded by light

brown on side of carapace; fingers of

chelae with red tips, subdistal black

bands.

Close relationships to O. rusticus are

not readily apparent. Species often

confused with, and at times considered

related to, O. rusticus include O. for-

ceps, O. placidus, O. putnami, O.

spinosus, and until synonymized with

Fig. 146.—Presumed native distribution of

Orconectes rusticus.

O. rusticus by Bouchard (1977), O.

juvenilis.

Distribution and Habitat.— O. rusti-

cus now occurs in New England. On-
tario, Michigan, Ohio, Indiana, Ken-
tucky, Tennessee, Illinois, Wisconsin,

Minnesota, Iowa, Missouri, and New
Mexico. It has been widely introduced,

presumably through use as fishing bait,

and the boundaries of its native range
(Fig. 146) now are difficult to determine.

However, at least its occurrences in New
England (Crocker 1979), Ontario
(Crocker & Barr 1968). Wisconsin
(Capelli & Munjal 1982). New Mexico
(Bouchard 1977). and Illinois are cer-

tainly the results of introductions. Once
introduced, O. ru5t?fU5 successfully dis-

places native species and expands its

range, apparently because it is a large

and aggressi\e species able to thrive

in impoundments and other disturbed

habitats (Berrill 1978; Capelli 1982;

Capelli & Munjal 1982: Capelli &
Magnuson 1983). Its continued use as

a li\e bait species is therefore unwise.

Taxonomic confusion about O. rus-



August 1985 Crayfishes and Shrimps of Illinois 413

Fig. 147.—Distribution of Orconectes rusti-

cus in Illinois. Open circle = Adams County
locality given by Hagen (1870) for "Cambarus
placidus," black dots = 1972-1984 collections.

ticus and its relatives has reigned since

their descriptions. "Cambarus wiscon-

sinensis Bundy," found at Normal
(Forbes 1876), is a synonym of O. virilis

(Hobbs 1972a) and is not a reference to

O. rusticus, as thought by Rietz (1912)

and Page (1974b). Brown's (1955)

records for "O. rusticus" all were for

Big Creek in Hardin County and are

treated herein as O. placidus.

"Cambarus placidus Hagen" was
recorded from Quincy by Hagen (1870)

and Forbes (1876) and considered by

Rietz (1912) to represent a record of

O. rusticus. Quincy is directly across

the Mississippi River from the Fabius

River system of Missouri which sup-

ports a population of O. rusticus or a

closely related undescribed species. The
Quincy record probably represents a

waif from the Fabius River population

of Orconectes and is plotted on the O.

rusticus map (Fig. 147).

In Illinois, O. rusticushas been found
recently in Peoria Lake, Tazewell

County (in 1973 and 1974), Powder
Horn Lake, Cook County (1975), Wolf
Lake, Cook County (1975, 1978, 1980),

Eagle Creek, Lake County (1975), Kent
Creek, Winnebago County (1977),

Nippersink Creek, McHenry County
(1979), in a backwater of Fox River at

Oak Point State Park, Lake County
(1982), and in Lake Michigan, 1 mile

east of Burnham Harbor, Cook County
(1984). All of these localities are heavily

used by fishermen or are near such areas,

and the presence of O. rusticus in Il-

linois is surely the result of bait-bucket

introductions. Except for Lake Michi-

gan and Wolf and Powder Horn lakes,

which are in the Lake Michigan drain-

age, and Kent Creek, which is a tributary

of the Rock River, all localities are in

the Fox-Illinois River system (Fig. 147).

O. rusticus is reproducing in Illinois

(at least in Wolf Lake, where specimens

as small as 16 mm CL have been found)

and probably is supplanting native

species, as it is in southern Ontario

(Berrill 1978) and Wisconsin (Capelli &
Munjal 1982). Hybridization between

O. rusticus and O. propinquus and
between O. rusticus and O. limosus

has been recorded in Wisconsin and
Massachusetts (Capelli & Capelli 1980;

Smith 1981) and appears to represent

an intermediate step in the displace-

ment by O. rusticus of these native

species. In Illinois, it appears to be

hybridizing with O. virilis in Wolf
Lake. O rusticus lives in rocky riffles,

pools, and along wave-swept lake

margins.

Life History.—In fish ponds in Ohio,

Langlois (1935) found mating to occur

in September and October; following

copulation, the females burrow into

banks. Oviposition occurs in a few

females in October, but mostly in April

and May, when females are 1 year old.

Eggs hatch in about 20 days and remain

attached to the female for al)out 5 days.

Sexual maturity is reached in the fall



414 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

4

I

Fig. 148— Orconecfes stannardi. A, dorsal view of carapace: B, dorsal view of right chela;

C, annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of

form I male; F, lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 115

following one summer's growth.

Prins (1968) studied O. rusticus in a

stream in Kentucky and found that

mating peaks in September and Octo-

ber, females oviposit from February

through June at about 22-24 months,

eggs hatch in May after being carried

by the female for 4-6 weeks, young
remain attached to the mother for 3

weeks {through April and May), sexual

maturity is reached at about 15 months
(about 18 mm CL), the sex ratio among
juveniles is 1:1, and the species reaches

a maximum longevity of about 3 years

and a maximum CL of 45 mm. Counts of

ovarian eggs in 43 females ranged from

54 to 357. The smallest female with eggs

attached (55 eggs) was 17 mm CL; _the

largest, with 231 eggs, was 38 mm CL.

The relationship between the number
of eggs (N) and carapace length (L)

of 49 females was N = -91.49 + 8.3 IL,

with r = 0.86. The species feeds mainly

on plants and detritus and has been

observed feeding out of water along

the banks. During winter, O. rusticus

typically burrows into stream banks

and into interstices in the substrate.

Form I males have been found in July

and August in Ontario (Crocker Sc Barr

1968), in June in Maine (Crocker 1979),

and in July and September in Iowa

(Phillips 1980). Females in berry were

collected in April in Iowa (Phillips

1980). Busch (1940) found that it took 20

Jays for eggs to hatch at 20°-22°C.

.\mong the nine Illinois collections

(made from May through September),

form I males (20.5-34.0 mm CL) are

present in August and September. No
ovigerous females were found. Some
Illinois specimens approach the maxi-

mum size recorded for the species; the

largest Illinois male (form II) is 40.5

mm,
CL.

and the largest female is 41.5 mm

PageOrconectes stannardi

(Fig. 148)

Orconectes stannardi Page 1985

Description.— R(jstrum excavated;

well-developed median carina; long

acumen; margins moderately thick.

subparallel, slightly converging me-

dially, terminating in spines. Carapace

flattened dorsoventrally, with cervical

spines; suborbital margin weakly an-

gular. Areola moderately wide, narrow-

est part about 15-25 percent of length.

Chela large, heavily punctate; palm
with two rows of tubercles on mesial

margin. Form I gonopod terminates

in two short, straight elements: a sclero-

tized central projection and an unsclero-

tized mesial process with spur about

middle of caudal surface; shoulder on
cephalic surface at base of central pro-

jection. Olive green to light brown and

usually heavily speckled with dark

brown dorsally; fingers of chelae with

red tips, subdistal black bands.

Distribution and Habitat.—O. stan-

nardi is a member of the O. propincjuus

species group that is endemic, and

Fig. 149— Distribution of Orconectes stan-

nardi. Open circles = localities given by Rietz

(1912) and Brown (1955) for "O. propinquus"

and "O. indianensis." black dots = 1972-1984

collections.



416 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

i^^f^^^W^^:^'''€l^^

'^aw 1 * „-w*k.:

Fig. 150—Orconecfes stannardi is most common along rocky stream margins such as this

one on the Little Wabash River, 3.5 mi NNW Louisville. Clay County, Illinois (8 October 1984).

po.ssibly autochthonous, to the Little suggesting that the species oiiginated
Wabash River system of Illinois. The sonietiine within the past 100.000 veais

region drained by the Little Wabash (Page 198.")). .\11 collections made since

was glaciated during the Illinoian 1972 are from the Little Wabash River
(about 100,000 y.b.p.) but not the Wis- proper (Fig. 149).

consinan (about 10,000 y.b. p.) advances, Riet/ (1912) and Brown (19.5.')) re-



August 1985 Crayfishes and Shrimps of Illinois 417

corded localities for O. propinquus and
O. indianensis in the Little Wabash
River system that almost certainly were
based on misidentified O. slannardi

(Page 1985). Data collected during the

present survey suggest that O. pro-

pinquus, O. indianensis, and O. stan-

nardi occur allopatrically and that

neither O. propinquus nor O. indianen-

sis occurs in the Little Wabash River

system. Unfortunately, the collections

made by Rietz and Brown cannot be

located and re-examined.

Although all collections of O. stan-

nardi that have been made since 1972 are

from the Little Wabash River proper,

some of the collections of Rietz (1912)

and Brown (1955) were from tributaries.

Collections of Rietz (1912) were made in

Big Muddy Creek between Richland
and Clay counties and in Skillet Fork
at Wayne City, Wayne County; the

former was identified by Rietz as O.

propinquus and the latter as O. in-

dianensis. Collections cited by Brown
(all as O. propinquus but which must
have been of O. slannardi) were made
in Dismal Creek, 2\ mi N lola. Clay

County; Salt Creek, 1 mi SE Effingham,
Effingham County; Blue Point Creek,
2'2 mi S Shumway, Effingham County;
Lost Fork, I'j mi E Omega, Marion
County; branch of Little Wabash River,

1'4 mi SW Trowbridge, Shelby County;
and Little Wabash River, 4 mi NE
Shumway, Effingham County.

Most individuals were found in shal-

low riffles composed of large flat stones

(Fig. 150). A few were found in deeper

water but always in association with

stones or accumulations of sticks and
other debris. The preference of O.

slannardi for rocky riffles is typical

of the Propinquus group of Orconecles,

the members of which typically hide

under stones and among debris. O.

slannardi is locally common in the

Little Wabash River.

Life History.—All seven collections

of O. slannardi presently available

(from November 1973, Nf)vember 1983,

May 1984, and August 1984) contain

form I males, and one (May 1984) con-

tains two ovigcrous females. All 20

males collected in November, 5 of 1

1

collected in August, and 1 of 25 collected

in May are form I. The two ovigerous

females collected in May 1984 were 20.7

mm and 28.9 mm CL and carried 124

and 184 eggs, respectively. Eggs average

1.9 mm in diameter. The largest speci-

men is a 38.3-mm CL female collected

on 22 August 1984; the largest male,

from the same collection, is a 30.5-mm
form L

Orconectes virilis (Hagen)

(Fig. 151)

Cambarus virilis Hagen 1870

Carnbarus debilis Bundy 1876

Cambarus wisconsinensis Bundy 1876

Cambarus couesi Streets 1877

Description.—Rostrum excavated;

moderately long acumen; no median
carina; margins thick, straight, barely

converging anteriorly, with terminal

spines. Carapace flattened dorsoven-

trally, with cervical spines; suborbital

margin bluntly angular. Areola narrow,

constricted anteriorly, narrowest part

about 6-7 percent of length. Chelae

large, heavily punctate; palm with two
rows of tubercles on dorsomesial mar-

gin. Form I gonopod terminates in two

long, caudodistally directed elements:

a sclerotized central projection and
a shorter unsclerotized mesial process.

Dorsally Hght brown to dark green-

brown; fingers of chelae without bright

red tips and subdistal black bands.

O. virilis occasionally occurs as a

blue color morph in Illinois and else-

where. Sugar Creek, a tributary of the

Sangamon River in McLean County,

contains a large number of blue O.

virilis. The upper reaches of Sugar

Creek are highly modified and receive

a large amount of pollution from
Bloomingion-Normal. and ihe large

number of blue crayfish may somehow
be related to the degradation of the

stream. Anderson (1975) descrilxxl a

4 1 -mm C;i, female O. virilis from the

Kisliwaukie Ri\er at De Kalb. Illinois,

that was "chalky white" overall except



418 Illinois Natural History Survey Bulletin Vol.33. ArL 4

i

Fig. 151.—Orconecfes virilis. A, dorsal view of carapace; B, dorsal, view of right chela;

C, annulus ventralis; D, mesial view of gonopod of form I male; E. lateral view of gonopod of

form I male; F, lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 419

Fig. 152.—Total distribution of Orconectes

virilis. The northern limits of the range are un-

known.

for daikl> pigmented eyes.

The closest relatives of O. virilis are

O. causeyi, which may be conspecific

with O. virilis (Hobbs 1974b), and O.

nais. O. fiais is \ery similar to O. virilis

morphologically but is distinct serolog-

ically (Pryor & Leone 1952). An area

of intergradation between O. inrilis and
O. nais may be present in southwestern

Iowa (Phillips 1980).

Distribution and Habitat.—O. I'nilis

ranges from New England across south-

ern Canada to the Continental Divide

in Montana, southeastern Wyoming,
and northeastern Colorado, and south

to the Ohio River in Ohio, Indiana,

and Illinois, the Missouri River in

Missouri, and the Platte River in Ne-

braska (Fig. 152). The northern limits

of its range are unknown (Crocker &
Barr 1968), but it occurs farther north

than does any other North American
crayfish.

O. virilis is the most common cray-

fish in Illinois and, in some streams,

exists in huge populations. It occurs

naturally throughout the state except

in the .Saline River system and in

streams draining the Shawnee Hills

and the eastern Coastal Plain (Fig. 153).

It is common to abundant over much
of its Illinois range, but less so in the

lower-gradient streams characteristic

of much of western and southeastern

Illinois. In the past, its abundance led

to its large-scale consumption by

humans (e.g., Creaser 1932), but this

no longer appears to be true, at least

in Illinois.

Although absent from the Shawnee
Hills, O. virilis occupies Clear Creek

and Mill Creek, both of which drain the

Ozark Plateaus Province in Union and
' Alexander counties. Habitats in the

"Illinois Ozarks" appear similar to

those in the Shawnee Hills, but several

animals occupy the Ozark Uplift and

not the Shawnee Hills, e.g., the snow
scorpionfly, Boreus brumalis; the

Fig. 153.— Distribution of Orconectes virilis

in Illinois: black dots = 1972-1982 collections.



420 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

Fig. 154.—Orconecfes virilis lives in a variety of habitats but usually is found in rocky areas

or accumulations of logs and debris such as this logjam on the Little Wabash River, 2.5 mi W
Watson, Effingham County, Illinois (8 October 1984).

slender madtom, Noturus exilis; the

fantail darter, Etheostoma flabellare;

and the green water snake, Nerodia
cyclopion (Webb, Penny, & Marlin
1975; Smith 1961, 1979).

A recent record for O. viriUs in an
impoundment in the Saline River sys-

tem (Berkel Lake, Saline County, 9

October 1977) is almost certainly the

result of a recent introduction. The
record is based on two individuals, one
of which is small (16.3 mm CL), sug-

gesting that the species is reproducing
in the lake.

In Illinois, O. virilis occupies rocky

streams (Fig. 154) and lake margins. It

usually occurs in moderate current

but is less common in swift riffles

(where, throughout much of Illinois,

it is replaced by O. propinquus) and
in sluggish pools (where O. inunimis
predominates). The largest populations
are found in areas where large flat stones

provide a preponderance of hiding
places. In lakes, O. virilis may occur
as deep as 9 m (Crocker &: Barr 1968).

Cralley (1932) found numerous bur-

rows belonging to O. virilis opening
just above the water line along the banks

of the Kaskaskia Ri\er in Champaign
County. Brown (1955) found a few

burrows of O. virilis in Illinois and
described them as being simple, with an

enlarged pocket at the lower end and
only one surface opening. Phillips

( 1980) found a burrow in Iowa about 30

cm deep with two terminal chambers

and a chimney about 5 cm tall. Hazlett

et al. (1974) found O. I'irilis burrowing
extensively along a stream and pond in

Michigan; burrows frequently had two
entrances, often one above the water

level. Rarely during the present survey

was O. I'irilis found in burrows, and it

appears to be much more common for

O. virilis to hide under rocks, even in

winter, than to burrow; however, as

discussed below, o\ igerous females may
habiiualh burrow.

Life History.—The wide-ranging and
often abundant O. i'irilis has been the

subject of numerous studies. In both



August 1985 Crayfishes and Shrimps of Illinois 421

Table 17.—Frequency of occurrence of form I males, females carrying eggs (ovigerous)

and females carrying young, in Illinois collections of Orconectes virilis.



422 Illinois Natural History Slrvev Bulletin Vol. 33, An. 4

in several Ontario lakes (Momot 1978).

Momot & Gowlng (1977) found much
lower egg counts among high-density

populations of O. virilis in Michigan
lakes. The number of attached eggs

on 402 females (22-35 mm CL) aver-

aged only 91.9. These females were

smaller than those found in Illinois.

Also, fecundity in these lakes was
thought to be related to density- de-

pendent processes, i.e., as the density

increased the number of eggs carried

by females decreased (Momot Sc Gowing
1977).

Elsewhere, form I males have been

found in April and June-October in

New England (Crocker 1979), May and
August in New York (Crocker 1957),

June-August in Ontario (Crocker &
Barr 1968), and July-April in Iowa
(Caldwell & Bovbjerg 1969). Form I

males may be as small as 25 mm CL
(Berrill 1978; Weagle 8c Ozburn 1972).

Females carrying eggs have been

found in April and May in Iowa (Cald-

well Sc Bovbjerg 1969; Phillips 1980),

April and May in Michigan (Pearse

1910; Momot & Gowing 1977) and New
Hampshire (Crocker (1979), May in

Rhode Island (Crocker 1979), and May-
July in Ontario (Crocker Sc Barr 1968).

Females with young attached have been

collected in May in Iowa (Phillips 1980)

and in June in Maine (Crocker 1979).

Some Illinois specimens appear to be

among the largest recorded, although

Creaser (1932) noted that in Wisconsin
the species "frequently attains a size

of over eight inches" (about 100 mm
CL). The largest Illinois specimens

are from reservoirs: a 59.5-mm CL fe-

male from Dawson Lake, McLean
County, collected on 25 September
1972, and a 59.2-mm CL form I male
from Baldwin Lake, Randolph County
collected on 2 November 1972. O. mrilis

is an agressive crayfish and, with its

large size giving it an advantage, ac-

tively excludes the often syniopic O.

iniDnniis from desirable hiding places

(Bovbjerg 1970). Intiaspecific domi-
nance was examined by Bovbjerg (1953).

The sex ratio among specimens col-

lected during the present sur\ey was

1,243 males: 1,1 82 females.

Genus Fallicambarus Hobbs

FaUicambarus Hobbs 1969

Gonopod with two large terminal

elements curved at about 90° angle to

shaft; central projection large and
bladelike. Ischium of third pereiopod

of male with hook. Opposable margin

of dactyl of chela with deep conca\ ity.

Only F. fodiens of the 14 recognized

species of Fallicambarus (Hobbs 1981)

occurs in Illinois. F. fodieiis is assigned

to the subgenus Creaserinus and is most

closely related to F. hedgepethi (see

comment below) and F. uhleri (Hobbs

1973).

Fallicambarus fodiens (Cottle)

(Fig. 155)

Astacus fodiens Cottle 1863

Cambarus argil licola Faxon 1884

Description.—Rostrum broad, ex-

cavated, with short acumen, lacking

marginal spines and tubercles, lacking

median carina. Carapace compressed,

lacking cervical spines; suborbital

margin smooth (not angular). ,\reola

obliterated. Chela large, punctate;

palm with one to three rows of tubercles

on mesial margin; dactyl with deep
concavity on basal half of opposable
margin. Form I gonopod terminates

in two elements, both cur\ ed at an angle
of about 90° to the principal axis of

the gonopod: a distally rounded sclero-

tized central projection and a short

proximally thick mesial process with a

pegiike tip. Dorsal cx:)loi variable, usu-

ally olive brown with dark brown
blotches, but often a uniform light

brown to rust red.

Distribution and Habitat.

—

F. fo-

difns is the most wide-ranging species

in its genus, extending, in the Great
Lakes (except Lake Superior) and Mis-

sissippi Ri\er drainages, from souiiiern

Ontario to wesieni Kentuckx (Fig. 156).

South of Kentucky it is replaced by the

clo.sely related, and probablv conspe-
cific (Burr S: Hobbs 1984; H. H. Hobbs



August 1985 Crayfishes and Shrimps of Illinois 423

Fig. ^55.—Fallicambarus fodiens. A, dorsal view of carapace; B. dorsal view of right chela,
C, annulus ventralis; D, mesial view of gonopod of form I male; E, lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



424 Illinois Natural History Survey Bulletin \'ol.33.Art. 4

Fig. 156.—Total distribution of Fallicambarus

lodiens. The southern limit of its range is un-

known.

personal communication), F. Iiedge-

pethi, which ranges to the Gulf Coast
and into Gulf drainages from Georgia
to Texas.

In Illinois it is known from the Ohio
(including the Wabash), Big Muddy,
Sangamon, Illinois, and Lake Michigan
drainages (Fig. 157). It appears to be

absent from western and extreme north-

ern Illinois and is rare in central Il-

linois. Although difficult to collect

because of its burrowing habits, present

records suggest that it remains common
in southern Illinois in the Ohio, Big
Muddy, Saline, and Little Wabash
systems.

During the present survey. F. fodieiis

was collected in central Illinois only
on the Sangamon River floodplain at

Allerton Park in Piatt County; however,
historical records suggest that the

species was formerly more common in

central and northern Illinois. The
northernmost records shown in Fig.

157 are based on a collection at the Il-

linois Natural Historv Survey labelled

Fig. 157.— Distribution of Fallicambarus

fodiens in Illinois. Large circles = 1890-1901

collections; small circles = collections made in

the 1950's; black dots = 1972-1982 collections.

-Ottawa, LaSalle Co., 111.. Sept. 1901,"

on Bovbjerg's (1952) study of F. fodiens

and O. propinquus in the Lake Michi-

gan drainage of southern Cook County,

and Bovbjerg's (1952) mention of the

presence of F. fodiens in Dead River at

Zion, Lake County, also a tributary of

Lake Michigan. Brown (1955) found F.

fodiens in a woodland pond (Sangamon
River system) 2.5 km SW Langley\ille,

Christian County.

In Illinois, F. fodiens lives on wooded
floodplains (Fig. 158) or wheie wooded
floodplains formerly occurred. It lives

in deep burrows and is in surface waters

(usually floodplain ponds) only dining

floods: 27 of .'51 collections of F. fodiens

made in Illinois since 1972 were made
from February through May, the period

of late winter-spring flooding, although

specimens also ha\ e been caught above



August 1985 Crayfishes and Shrimps of Illinois 425

Fig. 158.—Lower Simmons Creek, 5 mi N Golconda, Pope County, Illinois (26 October 1983).

Fallicambarus fodiens is common in burrows along the stream banks and, during floods, in

the stream.

ground in June, July, August, and

September. As floodwaters recede and
floodplain ponds dry, F. fodiens bur-

rows underground. In southern Illinois,

chimney-topped burrows on wooded
floodplains usually are those of F.

fodiens. Stands of river birch (Betula

nigra) are especially good indicators of

the likely presence of F. fodiens. In

Ontario, F. fodiens inhabits marshes,

drainage ditches, and ponds (Crocker

& Barr 1968).

>

Form I)

Fig. 159.—Size-frequency distribution of

Fallicambarus fodiens collected in April in

southern Illinois.

Table 18.—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Fallicambarus fodiens.



426 Illinois Natural History Survey Bulletin Vol. 33, Art. 4

I
Burrows constructed by F. jodiens

typically have one to three entrances,

often capped by chimneys, leading to

an oval resting cavity (Faxon 1885) and

leading down from the cavity 30-60 cm
is a narrow escape tunnel (Crocker &
Barr 1968). Soils having a high clay

content are probably necessary for the

deep burrows constructed by F. fodiens

(Crocker & Barr 1968).

Life History.—In a study in southern

Cook County, Illinois, Bovbjerg (1952)

found juveniles and gravid females in

woodland ponds as early as March. By

June the adults had disappeared, pre-

sumably into burrows, and only young
remained in the ponds. By 2 weeks prior

to the drying of the pond, all crayfish

had disappeared from the pond, either

by burrowing or emigrating. Individ-

uals were found (one at a depth of 1.2

m) throughout the summer by digging

in the dry pond bed down to the water

table. The refilling of the pond in the

fall was followed by a reinvasion of

F. fodiens, which was active in the pond
in November under a 5-cm ice cover.

F. fodiens can survive out of water

(at 20.5° C and 66 percent relative hu-

midity) for about 12 hours (Bovbjerg

1952), and overland migrations of F.

fodiens on warm (>5°C) humid
nights in March-May were docu-

mented by Cummins (1921). F. fo-

diens is omnivorous, and in northern

Illinois specimens, stomach contents

included plant fragments (especially

grass seeds), insect fragments, crayfish

appendages, an isopod, and a sala-

mander larva (Bovbjerg 1952).

Sexually mature (form I) males occur

in March and April in Michigan (Cum-
mins 1921) and in April (Table 18),

August, and October (Brown 1955)

in Illinois. The two form I males col-

lected during the present survey had
carapace lengths of 42 and 43 mm.
In Michigan, females have been

found with eggs in March and April

and with young in April and May
(Pearse 1910; Cummins 1921: Creaser

1931), in Indiana with eggs and young
in April (Hay 1896: Williamson 1907).

in Ontario with eggs in March and
April and young in May (Crocker & Barr

1968), and in Illinois with eggs in Feb-

ruary and March and young in Feb-

ruary, March, and April (Table 18).

Brown (1955) dug a female with at-

tached young from a burrow in south-

ern Illinois in October.

In the present survey, three females

with eggs and 24 females with attached

young were collected. The females with

eggs were 22, 28, and 35 mm CL, with

48, 68, and 162 eggs, respectively. Eggs
on the two smaller females, one col-

lected each in February and March,

averaged 2.2 mm in diameter; those on
the largest female, collected in March,

averaged 2.5 mm. Seven females col-

lected in February and March (30-44

mm CL) had 96-201 (mean, 132.1)

young attached.

The size-frequency distribution of

southern Illinois, April-collected F.

fodiens suggests that the species reaches

sexual maturity and dies in its second

year. Only males over 40 mm CL (second

year) among the indi\iduals collected

were form I, and all females over 30 mm
CL (second year) were carrying young.

All smaller males and females were

immature (Fig. 159). The sex ratio

among the combined April samples was
44 males: 42 females.

Genus Cambarus Erichson

Carnbarus Erichson 1846

Bartonius Ortmann 1905

Gonopod with two large terminal

elements curved at about 90° angle to

shaft; central projection large and
bladelike. Ischium of third pereiopodof

male with hook. Opposable margin of

dactyl of chela without deep concavity.

Cambarus contains about 77 species

(Hobbs 1981), of which four occur in

Illinois. Two of the Illinois species

(lenebrosus and rusticiformis) belong

to the subgenus Erebicambarus, one
(dio^enes) to Lacunicambarus. and one

(robuslus) to Punclicambarus. The
wide-ranging C. diogenes appears to be

a complex of species (Hobbs 1974b),



August 1985 Crayfishes and Shrimps of Illinois 427

Fig. 160— Cambarus tenebrosus. A, dorsal view of carapace;

C, annulus ventralis: D, mesial view of gonopod of form I male;

form I male; F, lateral view of gonopod of form II male

B, dorsal view of right chela;

E, lateral view of gonopod of



428 Illinois Natural History Survey Bulletin Vol. 33, An. 4

more than one of which may occur in

Illinois, as discussed in the species

account below.

Cambarus tenebrosus Hay
(Fig. 160)

Cambarus bartoni tenebrosus Hay 1902

Cambarus bartoni laevis Faxon 1914

Description.—Rostrum broad, shal-

lowly exca\ated, lacking median carina;

margins slightly converging anteriorly,

lacking terminal tubercles or spines;

acumen short. Carapace dorsoventrally

flattened, cervical spines absent (north-

ern population) or present (southern

population); suborbital margin gently

angular. Areola moderately wide, nar-

rowest part about 13-14 percent of

length, with at least four punctations

across. Chela large, heavily punctate;

palm with one or two rows of tubercles

on mesial surface. Form I gonopod
terminates in two elements, both curved

at an angle of more than 90° to the

principal axis of the gonopod; a distally

rounded sclerotized central projection,

and a large tapering to broadly rounded
mesial process. Dorsally rust red over-

all, with abdomen slightly browner
than carapace.

In a discussion of the distribution and
phylogeny of species of Cambarus,
Hobbs (1969) depicted the range of C.

(Erebicambarus) laevis as occurring

mostly north of the Ohio River and that

of the consubgeneric C. tenebrosus as

being south of the Ohio River. Hobbs
(1974b) separated the two species on the

relative width of the areola ("at least

4 punctations across narrowest part"

in C. tenebrosus; "no more than 3

punctations across narrowest part" in

C. laevis) and the shape of the mesial

process of the gonopod ("broadly

rounded distally" in C. tenebrosus;

"strongly tapered, often subacute" in

C laex'is).

Populations of the subgenus Erebi-

cambarus occurring in southern Il-

linois have been referred lo as C. bartoni
brevis (Rietz 1912), C. bartoni laei'is

(Brown 1955), C. laevis (Hobbs 1968,

Fig. 161.—Total distribution of Cambarus
tenebrosus.

Fig. 162,

brosus in I

lections.

—Distribution of Cambarus tene-

linois; black dots = 1972-1982 col-



August 1985 Crayfishes and Shrimps of Illinois 429

1969, 1972a; Page 1974b: Peck & Lewis

1977), C. ornalus (Peck & Lewis 1977),

and C. teuebrosus (Peck & Lewis 1977).

It now appears that the correct name for

the southern Illinois populations is C.

teuebrosus. Populations extend across

the Shawnee Hills of southern Illinois,

into the Cumberland River drainage of

western Kentucky, and into the general

range of C. teuebrosus with no notice-

able mor|)hological discontinuities.

In \'ermilion County in east-central

^^

"K^uX^^jti
Fig. 163.—Spring emptying into Big Creek in Hardin County, Illinois (8 October 1984). This

and other springs in the Shawnee Hills provide the best habitat in Illinois for Cambarus tene-

brosus.



430 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Fig. 164 —Cambarus rusticiformis. A, dorsal view of carapace; B, dorsal view of right cfiela;

C, annulus ventralis; D, mesial view of gonopod of form I male; E. lateral view of gonopod of
form I male; F, lateral view of gonopod of form II male.



August 1985 Crayfishes and Shrimps of Illinois 431

Illinois is a population of Erebicam-

barus discovered in 1977. It differs from

C. tenebrosus in southern Illinois by

having a narrower areola and by lacking

cervical spines (although tubercles

often are present). No form I males have

been found. If C. laevis is a valid species,

the X'ermilion County population is

morphologically and geographically

(jide Hobbs 1969) referable to that

taxon. However, the absence of dis-

continuities in the geographic variation

in morphology among populations

assignable to the C. tenebrosus-C. laevis

complex suggests a lack of reproductive

isolation among populations and that

only one species is recognizable. In-

dividuals in the northern part of the

range of the species have narrower

areolae, lack cervical spines, and ap-

parently have more tapered mesial

processes on the gonopods. H. H.

Hobbs, Jr. (personal communication

1983) suggests that "when adequately

studied, laevis will prove to be a syno-

nym of tenebrosus." Pending such a

study, all Illinois populations are re-

ferred to as C. tenebrosus.

Distribution and Habitat.— C. tene-

brosus occurs in central and south-

eastern Indiana, the Vermilion River

system in east-central Illinois, the

Shawnee Hills of Illinois, western and
central Kentucky, central Tennessee,

and northern Alabama (Fig. 161). It

appears to be absent in southwestern

Indiana.

In Illinois and elsewhere, C. tene-

brosus occupies rocky springs and
spring-fed headwaters and creeks. It

hides under stones, sometimes forming

shallow excavations in the stream bed.

Brown (1955) cited "small piles of mud
at the edge of rocks" as an indicator

of the presence of the species. Its affinity

for spring-fed headwaters often results

in its occupancy of caves.

In southern Illinois, C. tenebrosus is

restricted to the Ohio River drainage of

Hardin, Pope, Johnson, and Union
counties (Fig. 162). It is most common
in Big Creek, a moderate-sized stream

in Hardin County fed by numerous

Fig. 165.—Total distribution of Cambarus
rusticiformis.

Fig 166— Distribution of Cambarus rustici-

formis in Illinois; black dot = 1975 collection.



432 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

springs (Fig. 163). Elsewhere in Illinois

it has been found only in Willow Creek

(Vermilion River system) in Vermilion

County, Illinois (Fig. 162), where it

presumably is distributionally contig-

uous with the Indiana population.

The Illinois and total ranges of C.

lenebrosus are quite similar to those

of the zigzag salamander (Plethodon

dorsalis) although the salamander has

dispersed into Clear Creek, a tributary

of the Mississippi River, in Alexander,

Union, and Jackson counties (Smith

1961).

C. tenebrosus, first recorded in Illi-

nois (as C. bartoni brevis) by Rietz

(1912), probably has essentially the same
distribution now as it had prior to the

arrival of man. However, the water table

of southern Illinois has been lowered

within historic times, and some springs

may have disappeared or at least are

smaller than before, reducing the habi-

tat available for C. tenebrosus. Such
reductions in habitat have caused some
spring-inhabiting fishes (Phoxinus
erythrogaster, Rhinichlhys atratulus)

to disappear from southern Illinois

(Smith 1979).

Life History.—Prins (1968) studied C.

lenebrosus in a stream system in Ken-
tucky and found it to be most common
in constant-temperature headwaters.

Most adults were found in burrows or

under large rocks, but young and sub-

adults were found in open-stream
environments. The diet consisted pri-

marily of vascular plants, especially

fallen leaves from the riparian habitat,

and filamentous algae. Other food items

included detritus, aquatic insects, and
crustaceans. Hatching occurs in July
and August after eggs have been carried

by the female for at least 25-30 days.

Growth continues throughout the year,

including winter, and sexual maturity
is reached at about 20-22 months and
10 mm CL. Mating occurs in winter
and spring. Mature Irmales oviposit

in June and July at about 22-23 months
and probably again at 34-35 months.
Egg counts on seven females (44-52 mm
(;L) ranged from 186 to 266. Maximum

CL was found to be about 65 mm and
maximum longevity about 36-38

months. The sex ratio among 3,235

specimens was 1 male: 1.03 females.

No form I males or females carrying

eggs or young were present among the

40 collections of Illinois C. tenebrosus

made during the present survey (all

months except September). Brown
(1955) reported collecting form I males

in August and October and a female

with attached young in October. All

of Brown's collections were made in

Hardin and Pope counties, Illinois.

A 46.6-inm CL female from Big Creek
is the largest Illinois specimen.

Cambarus rusticiformis Rhoades
(Fig. 164)

Cambarus rusticiformis Rhoades 1944

Description.— Rostrum narrows
anteriorly; margins elevated, concave,

and tipped with large knobs; acumen
moderate, ele\ated anteriorly; median
carina lacking. Carapace dorso\entrally

flattened, with large cervical spine,

small suborbital angle. Areola mod-
erately wide, narrowest part 16-18 per-

cent of length. Chela large. hea\ily

punctate; palm with single row of

flattened tubercles along mesial surface.

Form I gonopod terminates in two ele-

ments, both directed caudalK at an
angle greater than 90° to the principal

axis of the gonopod: a distally rounded,

sclerotized central projection and a

large distally tapering mesial process.

Distribution and Habitat.

—

C. rusti-

ciformis occupies the Cumberland
River drainage and the Barren Ri\er

system (Green Ri\er drainage) of Ken-

lucky and Tennessee (Bouchard 1976)

and, judging from one Illinois collec-

tion, the lower Ohio River (Fig. 165).

Two juvenile males (11.7 and 14.6 mm
CL) were collected in a rockv backwater
of the Ohio Ri\er near Lock and Dam
53, 4 km NE Olmsted, Pulaski County,

Illinois, (Fig. 166) on 16 July 1975.

Several later attempts to find C. rusti-

( iformis at the same and other sites on
the lower Ohio Ri\er were imsuccessful.



August 1985 Crayfishes and Shrimps of Illinois 433

r ^nL^V^^^f^!"^^/;"^
diogenes. A, dorsal view of carapace: B, dorsal view of right chela-

Pnr^T^^LT 'f
",°'

"^^n"
^'"^ °* aonopod of form I male: E, lateral view of gonopod oiform I male: F. lateral view of gonopod of form II male



434 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

Fig. 168.—Total distribution of Cambarus
diogenes.

The Ohio River site is about 67 river

km (42 miles) below the mouth of the

Cumberland River. The two specimens

may represent one of the westernmost

natural populations of the species, they

may have been waifs captured during a

downstream dispersal, or they may
have been transplanted as the result of

human activities. C. rusticiformis has

been introduced into the Paint Rock
River (Tennessee River drainage),

Alabama (Bouchard 1976). Collected

in the Ohio River with C. rusticiformis

were 12 Orconectes placidus, a species

with a similar overall distribution.

Elsewhere, C. rusticiformis lives in

rocky runs and adjacent pools and riffles

of fast-flowing creeks and small rivers.

Other ecological characteristics are un-
known.

Cambarus diogenes Girard

(Fig. 167)

Astacus fossor Rafinesqiie 1817. (Name
suppressed by Iiiieniaiional

Commission on Zooligical

Nomenclature, Opinion 522, 1958.)

Cambarus diogenes Girard 1852

Cambarus nebrascensis Girard 1852

Cambarus obesus Hagen 1870

Cambarus Diogenes var. Ludoviciana
Faxon 1885

Description.—Rostrum broad, ex-

cavated, with short acumen, lacking

marginal spines or tubercles, lacking

median carina. Carapace compressed,

lacking cervical spines; suborbital

margin angular. Areola obliterated.

Chela large, heavily punctate; palm
with two or three rows of tubercles on
mesial surface; dactyl with broad shal-

low concavity on basal half of oppos-

able margin. Form I gonopod termi-

nates in two elements, both directed

caudally at an angle slightly more than
90° to the principal axis of the gonopod:

a distally rounded, sclerotized central

projection and a slender mesial process.

Dorsal color varies from uniformlv

Fig. 169.— Distribution of Cambarus diog-

enes in Illinois; blacl< dots = 1972-1982 col-

lections.



August 1985 Crayfishes and Shrimps of Illinois 435

;-..^:^i*s^: -^^^2^"^'.::^^^:-:^^

^^P^**lj.^^
Fig. 170.—Chimney-topped burrows of Cambarus diogenes on the floodplain of a slough,

2 mi N Pleasant Grove. Johnson County, Illinois (9 July 1972).

red brown (with thorax lighter red) to

green with red outHning abdominal
segments, tips of chelae, and margins of

rostrum.

Marlow (1960) examined geographic
variation in C. diogenes and concluded
that only two subspecies could be rec-

ognized: C. d. ludovicianus in the Lake
Ponchartrain drainage and southern
Louisiana and C. d. diogenes through-
out the rest of the range of the species.

However, according to Hobbs (1969,

1974b), C. diogenes is a complex of

forms, and C. d. ludovicianus probably
is more widespread than Marlow
thought. Illinois specimens show tre-

mendous variation in the shape of the

carapace and rostrum and in coloration.

If several taxa presently are included in

"C. diogenes." more than one may be

found in Illinois. The only other de-

scribed species in the subgenus Lacuni-
cambarus are C. acanthura, restricted

to the Tennessee and Alabama drain-

ages of Tennessee, Alabama, and (ieoi-

gia (Hobbs 1981) and C miltus from
Baldwin Clounty, Alabama (Filzpatritk

1978b).

Dislribulion and Habitat.

—

C. diog-

enes ranges along the Atlantic Pied-

mont and Coastal Plain from New
Jersey and Pennsylvania south to cen-

tral Georgia, in Gulf drainages from
Georgia to eastern Texas, and north
in the Mississippi and Great Lakes
basins to western New York and Penn-
sylvania, Michigan, Wisconsin, Min-
nesota, and North Dakota. The western-

most populations occur in the Platte

Ri\er drainage of Colorado and Wy-
oming (Fig. 168).

C. diogenes occurs statewide in Il-

linois (Fig. 169) and is generally com-
mon. It is abundant in the Shawnee
Hills and on the Coastal Plain of south-

ern Illinois, less common in northern
and western Illinois. Its burrowing
habits preclude easy collecting, and
consequently, the number of (olle( lions

(Fig. 169) does not adetjuateh reflect

its abundance in Illinois.

C. diogenes first was recorded from
Illinois by Hagen (1870), who described

the spec imens (ollected at Lawn Ritlge

(Marshall County), Belleville, and
Fvanston as a new species, Cambarus
obesus. Forbes' (1876) only comments
on "('.. obesus" were: "Very tommon.
The largest in the state."

The burrowing l)ehavioi of C. diog-



436 Illinois Natural History Survey Bulletin Vol. 33, An. 4

Table 19—Frequency of occurrence of form I males, females carrying eggs (ovigerous),

and females carrying young, in Illinois collections of Cambarus diogenes.



August 1985 Crayfishes and Shrimps of Illinois 437

Fig 171.-Cambarus robustus. A. dorsal view of carapace; B, dorsal view of right chela-
C, annulus ventralis; D, mesial view of gonopod of form I male; E. lateral view of gonopod oftorm I male; F, lateral view of gonopod of form II male.



438 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

were collected from February through

July (except in May), and in October

and November (Table 19); Brown (1955)

found form I males in Illinois from

March through September, except in

July. The primary peak of occurrence

is in February and March, and a second-

ary peak occurs in November (Table 19).

Elsewhere, matings have been observed

in March, April, May (Hargitt 1890;

Hay 1896; Evermann Sc Clark 1920), and
October (Williams & Leonard 1952). In

Louisiana, form I males were found in

March, April, and October (Penn &:

Marlow 1959) and in Georgia in Jan-
uary, April, and October (Hobbs 1981).

Ortmann (1906) recorded form I males

in Pennsylvania from March through
November. Among the C. diogenes

examined by Marlow (1960), form I

males were present in every month ex-

cept January, but were most prevalent

in April and September. Although the

occurrence of form I males suggests

that mating in C. diogenes may occur

in almost any month, activity probably

peaks in late winter-early spring (Feb-

ruary-April) and in fall (September-
November).

Ovigerous females have been found
in January (Bundy 1877), April (Hay
1896; Evermann &: Clark 1920: Creaser

1932), and May in Indiana (Williamson
1907); in April and May in Pennsyl-
vania (Ortmann 1906) and Iowa (Phil-

lips 1980); in April (Williams & Leonard
1952) and May in Kansas (Harris 1900);

from late March to May in Wisconsin
(Graenicher 1913); and in September
in Georgia (Hobbs 1981 ). Marlow ( 1960)

examined o\igerous females from
March (1 female), April (19), May (17),

and October (I). Females carry young
in May and June in Pennsylvania
(Ortmann 1906) and in Indiana (Wil-
liamson 1907; Evermann &: Clark 1920),

and in June in Michigan (Creaser 1932).

In Illinois, females were found to carry

eggs from January through Ma\, except

Fig. 172.—Total distribution of Cambarus
robustus.

Fig. 173,— Distribution of Cambarus robus-

tus in Illinois. The two records (Adams and
Macon counties) are from Faxon (1885) and
Rietz (1912).



August 1985 Crayfishes and Shrimps of Illinois 439

in February, and young in May and
June (Table 19).

Because of the difficulty in obtaining

adult C. diogenes, few females with

eggs or young attached were collected

in the present survey. Five females

(43.7-56.4 mm CL) collected in April

and May were carrying 183-518 (mean,

295.2) eggs. The highest number of eggs

was on the smallest female. Eggs varied

in diameter from 2.1 to 3.0 mm, and
unlike other crayfishes examined dur-

ing the present survey, in C. diogenes

egg diameter has a significant corre-

lation (r = 0.97) with length of the fe-

male: egg diameter = -1.280 + 0.077

CL.
A 48.5-mm CL female collected in,

Johnson County on 19 May 1973 had
606 early-instar young attached; a 47.2-

mm CL female collected in Christian

County on 8 June 1979 had 45 late-instar

young attached. Two females collected

in Indiana in 1906 were carrying 87

and 215 young (Williamson 1907).

Cambarus robustus Girard

(Fig. 171)

Cambarus robustus Girard 1852

Description.—Rostrum moderately

broad, shallowly excavated, lacking

median carina; margins converge an-

teriorly, lack terminal tubercles or

spines; acumen moderately large. Cara-

pace dorsoventrally flattened, with

large cervical spines; suborbital margin
angular. Areola moderately wide, nar-

rowest part about 12-17 percent of

length. Chela large, heavily punctate;

palm with two rows of tubercles on
mesial surface; base of fixed dactyl

with deep dorsal and ventral imjjres-

sions. Form I gonopod terminates in

two elements: a distally rounded, sclero-

tized central projection curved at an

angle of more than 90° to the principal

axis of the gonopod, and a large gently

tapering mesial process curved at about
90° to principal axis. Dorsally green

brown.
Distribution and Habitat.—C. ro-

bustus ranges from Connecticut and

southern Ontario south to northwestern

North Carolina and eastern Kentucky

and west to Michigan and central In-

diana (Fig. 172). It occupies rocky areas

of fast-flowing streams, and sometimes
is found in rocky lakes and ponds
(Crocker &: Barr 1968; Berrill 1978).

The only Illinois records (Fig. 173)

are from the late nineteenth and early

twentieth centuries. Faxon (1885) re-

ported C. robustus from Decatur

(Macon County, Sangamon River sys-

tem), and Rietz (1912) reported four

specimens from Quincy (Adams
County, Mississippi River drainage).

Although the Quincy specimens cannot

be located, the Decatur specimens are

in the U.S. National Museum (USNM
63291) and unquestionably document
the former presence of the species in

the state. C. robustus is rare even as far

west as Indiana (Eberly 1955), and the

Illinois collections must have repre-

sented relict populations left over from

a more widespread distribution in a

cooler postglacial climate. Many
streams today around Quincy are

spring-fed, and considerable effort was

expended in unsuccessful attempts to

locate surviving populations of C.

robustus in what appear to be suitable

habitats. The Sangamon River, flowing

through Decatur, was badly polluted

in the early part of this century (Jewell

1920), is now impounded by Lake De-

catur, and appears unlikely to support

a population of C. robustus.

Life History.—Crocker (1957) re-

ported form I males in New York col-

lections made from April through Octo-

ber and observed copulation in October

and May (the latter in a lamprey trap).

Form I males have been collected in

Pennsylvania in May and July-No-

vember; the smallest was about 63 mm
total length (about 32 mm CL) (Ort-

mann 1906). In southern Ontario, form

I males were 25-55 mm CL (Berrill

1978). Ovigerous females have been

found in July in New York (Crocker

1957) and Pennsylvania (Ortmann
1906); the Pennsylvania female, 84 mm
total length (about 42 mm CL), carried

228 eggs. Females with young attached



440 Illinois Natural History Survey Bulletin Vol. 33. Art. 4

have been observed in April and August

in New York (Crocker 1957). Young feed

on immature insects; adults feed mainly

on aquatic plants (Greaser 1934).

CONSERVATION
Unfortunately, it appears that Macro-

brachium ohione and Cambarus ro-

biistus already have disappeared from

Illinois. C. robustus may have dis-

appeared from Illinois naturally rather

than because of man-induced changes

in the environment. Our earliest records

indicate that it was relict in Illinois,

presumably having been reduced from a

more widespread distribution to small

areas near Quincy and Decatur. Else-

where it inhabits cool to cold streams

and apparently was reduced in warm
postglacial Illinois (probably during

the Xerothermic period) to small popu-

lations that subsequently were imable

to perpetuate themselves. A7. ohione

probably disappeared because of the

extensive modification and degradation

of Illinois' large rivers. Especially

harmful loM. ohione would have been

the loss of aquatic vegetation associated

with increased siltation, channeliza-

tion, and chemical pollution.

Unless protective measures are taken,

several more species of native decapods

are likely to disappear from Illinois.

The following four species have re-

stricted ranges in the state and are

threatened with extirpation. They
should receive as much protection as

possible by our adding them to the

Illinois List of Endangered and Threat-

ened Species and protecting their

habitats.

The distribution of Orconectes in-

dianensis has been reduced dramatically

in Illinois as a result of severe pollution

and other major modifications of the

Saline River system. Remaining popu-
lations are restricted to the South Fork

of the Saline River in Gallalin, John-
son, Pope, Saline, and Williamson
(ounties, Robinette (Eagle) Creek in

(.allaiin Comity, and Honey Creek in

ilavdin C^ounty. Elsewhere the species

occurs only in a small area of Indiana.

Orconectes kentitckiensis occurs only

in Big, Hosick. and Peters creeks in

Hardin Comity, and although the dis-

tribution of this species in Illinois

probably has changed little historically,

its persistence is threatened by modifica-

tions of the riparian habitats in Hardin

County. Trees have been remo\ed from

many miles of stream bank, resulting

in less shading of the stream and higher

water temperatures. Water has been

diverted in ever-increasing amounts
from its natural drainage for use in

agriculture. The lowered water table

is reducing the size of Big Creek. Else-

where, O. keutuckiensis occurs only in

a small area of northwestern Kentucky.

Orconectes placidus is common
throughout much of Kentucky and
Tennessee, but in Illinois it maintains

a sizeable population only in Big Creek

in Hardin County and is threatened by

the same stream modifications threat-

ening O. kenluckiensis.

Orconectes lancijer is restricted in

Illinois to Horseshoe Lake in .\lexander

County. Although under the supervi-

sion of the Illinois Department of Con-

ser\ation, the lake has been severely

modified in recent decades, and much
of it now is surrounded by agricultural

fields ami grasses. If the unusual biota of

Horseshoe Lake is to persist, subsequent

modifications of the lake shoidd be

allowed only after carefid consideration

of their iin ironmental inipaci. Else-

where O. lancifrr occurs imcoinmonly
ihoughout the former Mississippi Em-
bayment.

ACKNOWLEDGMENTS
I am extremely indebted to Mr. Craig

W. Ronto for the execution of most of

the figures appearing in this pidilica-

tioii and lo Dr. H. H. Hobbs, jr.. for

laxononiic comisel, distributional in-

formation, and a thorough review of

the manuscript.

I am indebted also to B. M. Burr and

R. W. Bouchard for taxonomic (inmsel

during the study, to J. .\. Beatty, P. W.



August 1985 Crayfishes and Shrimps of Illinois 441

Smith, G. C. Sanderson, and C. Burnett

for helpful reviews of the manuscript,

to Bernice P. Sweeney for typing the

manuscript, and to the following col-

leagues and friends for assistance with

field work and/or providing specimens:

J. Allen, R. V. Anderson, N. A. Ashford,

S. S. Birky, L. Boscarine, J. K. Bouse-

man, J. A. Boyd, R. A. Brandon, A. R.

Brigham, W. U. Brigham, B. Britton,

J. Brower, K. Brummett, J. Buerger,

B. M. Burr, P. A. Burr, M. K. Butcher,

R. W. Clegern, L. E. Cordes, A. Covich,

F. Cruse, K. S. Cummings, D. M. Cur-

rent, R. Cygan, L. R. Davis, D. Dufford,

W. H. Ettinger, R. A. Evers, J. Fairchild,

J. Grady, R. Grosser, L. R. Hanebuvg,
W. Herridon, R. Hite, R. W. Horner,

M. Hoverstein, D. L. Johnson, T. M.
Keevin, W. L. Keller, M. King, M.
Klutho, L. Kolczak, J. Langbein, E. A.

Lisowski, E. L. List, K. Lubinski, C.

Maier, J. C. Marlin, W. Mathis, W.
Matsunaga, R. L. Mayden, J. McNur-
ney, R. L. Moran, M. A. Morris, V. L.

Morris, D. A. Nolan, L. D. O'Bryant,

S. D. Ogle, D. Osterbur, E. M. Page,

M. L. Page, V. M. Page, P. J. Paladino,

P. Parrillo, G. Pefrates, I. Polls, A.

Pulley, F. Putz, M. Ratke, M. E. Retzer,

L. R. Richart, R. Rogers, C. W. Ronto,

K. Russell, D. Sallee, M. W. Sanderson,

R. T. Schaaf, R. Schacht, D. W. Schem-
ske, P. W. Smith, S. Smith, L. J. Stan-

nard, R. Stinauer, J. Sublett, L. B. Sulo-

way, C. S. Swanson, B. Taubert, R.

Thom, R. Thomas, J. Thomerson, J.

Tranquilli, W. J. Tucker, R. Twillman,

J. D. Unzicker, W. S. Vinikour, W.
Ward, T. Wayne, D. W. Webb, J. Webb,
M. J. Wetzel, F. Winter, L. A. Woodrum,
R. D. Wrisberg, and L. S. Zimmer.

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INDEX
•147

ncanthura. Caxibaru.s, 435

aumlhurus. Miurnbriu liiuiu. 356

aiuliis, C:/unharu\. 376
aculus, Cambaru.s btaniiingii. 376
acutus. Pxocambanis, 376
alnbametisii. Orconcctcs, 390
antrorum. Pnlaemonetes, 359

argillicota. Canibarus, 335, 422

A.slacus. 422
jodtens. 422

fossor. -i'i-i

wi.scon.siiii'>isis, 335, 417

larrinu.'i, Ma< robrat htuiii, 356
cau.seyi, Onoiintes, 419
Clarkii, Cambarus. 381

clarkii. Procambarus. 381

Conservation, 440
louesi, Canibarus, 417

Crayfish Life Cycle. 343

Creaserinus, 335
cuevachicae, Procambarus acutus.

cummingi, Palaemoneles, 359
376

Barbicambarus, 362

barloni, Catribarus, 428

Barlonius, 426
biseclus. Orconecles, 338

biacki, Cambarellus, 368

blaudingu. Procambarus. 376
blandingii. Procambarus acutus. 376

Boiu hardma. 362
brevis, Camharus bartoni. 335, 428

Cambarellinae, 335

Cambarellus. 335, 363

fc/ac*), 368
diminutus, 368
/cs/ifj, 368
ninae. 368
pufr, 366
schmilti. 368
shufeldtii. 363
/cva/H(i, 368

C:ambaridae, 335, 362
Cambarinae, 335

Canibarus. 335, 426
acanthura, 435

af!((uj, 376
argitlicola, 335. 422
bartoni, 428

ferci'ii. 335, 428
/flpi^w. 428
tenebrosus. 428

blandingti acutus. 376
C/ar/(H.'381

couesi, 417

rfc6i7(i. 417

diogenes. 434

var. Ludoviciana. 434

ludovicianus, 435
jaxonii, 400
gracilis, 370
/H<fcfe.si, 338
immurns. 388

spmtrostris. 388

indianensis. 394

jui'enilis, 412
lanojer. 400
/flfi'ii, 428

miltus, 435
nebrascensis, 434

ob«u5. 335. 434

ornatus. 129

placidus. 404
proptnquus, 406
rofci/s/ui, 439
rusticiformis, 432

r».(/KU.s. 412

signifer, 388
.s/>'gH<.v. 335. 376
tenebrosus, 428

viae-i'iridis, 378

turi/i.s, 417

debilis. Canibarus. 417

Derapoda. 335

diminulus, Cambarellus, 368
diogenes, Canibarus, 434

Dirigicambarus, 335, 363

Distocambarus, 362

Erebuurnbarus, 335, 428

exiUpes, Palaemoneles, 335, 360

Extraliniital .Species and Studies, 336

Fallicambarus. 335, 422
fodiens, 422

hedgepethi. 422
ulileri, 422

Faxonelta. 362

faxonii. Canibarus. 400

Faxonius. 386
immunis pedianus. 388

fodiens. .-istai us, 422

fodiens. Fallicambarus. 422

forceps, Orconectes, 412

fossor, Astacus. 434

Freshwater Shrimp Life Cycle, 345

Geological History of Illinois, 339

Girardielta. 335, 371

gracilis, Canibarus, 370

gracilis, Procambarus, 370

Historical Studies of Illinois Decapods, 335

harrisoni. Orconectes, 338. 396

hedgepethi, Fallicambarus, 422

Hohbseus, 362
holthuisi. Palaemoneles, 359

hubbsi, Canibarus, 338

/iy/as, OrfOfiff(«, 338

illinoiensis, Orconectes, 386

immiiMi,?, Canibarus, 388

immunis. Orionectes. 388

immunis \ pedianus. Orconectes, 390

indianensis, Canibarus, 394

indianensis, Orconectes, 394

/ou'ac'i.siA. Orconectes, 406

juvenilis, Canibarus. 412

juvenilis, Orconectes. 412

kadiakensis. Palannonetes, 359
kentuckiensis, Orconectes. 396

Key to Decapods of Illinois. 348

Key to Illinois Oayfishcs Based on Form I M.iles. 353

Key to Illinois Spec ies. 345

l.aiuniuimbarus, 335, 435



448

lancifer, Orconectes, 400
laei'is, Cambarus, 428
lan'is, Cambarus bartoni, 428

lancifer, Cambarus. 400

lesliei, Cambarellus, 368

liberorum. Procambarus. 371

limosus, Orconectes, 412

Ludoviciana, Cambarus diogenes var., 434

ludovicianus, Cambarus diogenes, 435

luteus, Orconectes, 338

Macrobrachium, 335, 356
acanlhurus, 356
carcinus, 356
ohione, 356
oljersii. 356

medius, Orconectes, 338
millus, Cambarus, 435

r!a«, Orconectes, 338. 419
Natural History, 343
r!f6raicfn5«, Cambarus, 434

ninae, Cambarellus, 368

obesus, Cambarus, 335, 434

ohione, Macrobrachium, 356
Ohionis, Palaemon, 356
oljersii, Macrobrachium, 356
Orfonpf/«, 335, 386

alabamensis, 390
bisectus, 338
fOUiiC)!!, 419
forceps, 412
harrisoni, 338, 396
/i5)/a5, 338
illinoiensis, 386
immunis, 388
immunis x pedianus, 390
indianensis. 394

lowaensis, 406
juvenilis, 412
kentuckiensis, 396
lancijer, 400
limosus, 412
/u(fU5, 338
medius, 338
riflii, 338, 419

peruncus, 338
placidus, 404
propinquus, 406
punctimanus, 338
putnami. 412
quadruncus, 338
rhoadesi, 390
riiiiifuj, 412
sloanii, 396
spinosus, 412
stannardi. 415
tricuspis, 338
validus, 390
wiriiii, 417
wrighti, 394

orna(ui, Cambarus, 429
Ortmannicus, 369, 376, 378

Palaemon, 356
Ohionis, 356
sattei, 356

Palaemonetes. 335, 358
an^rori^m, 3.59

(ummin^i. 359
Mi7ipci,'335, 360
holthuisi, 359

kadiakensis, 359
paludosus, 358
/pxanui, 359

Palaemonidae. 335, 356

paludosus, Palaemonetes, 358

Pandicambarus, 335, 368

Paracambarus, 369

Pacijasticus. 362

pedianus, Faxonius immunis, 388

peruncus, Orconectes, 338

placidus, Cambarus. 404

placidus, Orconectes, 404
Procambarus, 335, 369

acij/ui, 376
acutus, 376
cuevachicae, 376
blandmgii, 376

blandingii. 376. 378

c/arAn, 381

gracilis. 370
liberorum, 371

reimeri, 371

troglodytes, 335

inaeviridis, 378
propinquus, Cambarus, 406
propinquus, Orconectes, 406
pufr. Cambarellus, 366

Puncticambarus, 335
punctimanus, Orconectes, 338
putnami, Orconectes, 412

quadruncus, Orconectes, 338

reimeri, Procambarus. 371

rhoadesi. Orconectes. 390
robuslus, Cambarus, 439
ruslicijormis, Cambarus, 432

ruj()fui. Camfcaru5. 412

ru.s<ifuj, Orconectes, 412

sallei, Palaemon, 356
Scapulicambarus, 335. 383

schmitti. Cambarellus, 368
shujeldtii, Cambarellus, 363

signijer. Cambarus. 388

sloanii, Orconectes. 396

sptnirostris. Cambarus immunis. 388

spinosus, Orconectes, 412

stannardi, Orconectes, 415

i(Vg(U5, Camiarui, 335, 376
Systematic Accounts, 356

lenebrosus, Cambarus, 428

tenebrosus, Cambarus bartoni, 428

(cvn?iui. Cambarellus, 368

(rva>ii;i, Palaemonetes, 359
tricuspis. Orconectes. 338
Troglocambarus. 362

troglodytes, Procambarus, 335

uhleri, Fallicanibarus, 422

validus, Orconectes. 390
I'lae-viridis, Cambarus, 378
viaei'tridis, Procambarus, 378

viritis, Cambarus, 417

viritis, Orconectes, 417

!i'i.sfo>i.su!f«si.v, Cambarus, 335, 417

wrightt. Orconectes. 394

Zoogeography of Native Illinois decapods. 339



WtT/.KI.. Fauii 1).. B.S., Trihnuai Awtslanl
CIrossktt. I.okkiI':. W.S.. Junto j Tn hnutil A\\t\lant

Cl'.MMiN<;s, Kkvin S,. M.A., }um<n Trthnual .hM^lont

C^ARNKY, Dni'(.i,A.s A,. M.A., }unu>T Trt/tttmil AyMstant

Irish. Jjn^RFV A., B.S.. Junior Tri Ituunl .\\\i\lnnt

Pk\(ITH.i,i. Pamh.a A.. U.S.. Juixuti Tnhnunl .Iwixtant

Sandbkrc;. SiitRRi I... B.S,. Junun Trthuual .Iwislant

Smkrman. RKNt->. B.S., Junun Trthnual AsMstniil

IiMAN. Mahv( ARCH,. B.S.. Juutoi Trtiiiiual .t.wislanl

V'ANDrRAii. (ii.KNiJV C... Jututi} Trthuunl Assntant

SECTION OF WILDLIFE RESEARCH
SANDtRsoN. (,|KN C. Pill).. WthHiff Sf)r( uili^l and Urnil

Bki.i.roM':. Frank i... Sc.D.. IVtlilUfr Sfiftialist and Prinapal
S( irnlisl

CrRABKR, Ri<:hard R.. Ph.D.. Orntl/tolofii.si and Hriiit ipa( St irnlisi

hmrTiltt\

Andfrson, Wie.i.iam I... M.S., Wildlifr hcolo^ist

Edwards. VVh.iiam R.. Ph.D., IVildliff E(olo^i.\l

Grabfr. Jf an \V.. Ph.D., (>rnilholoiii.\i

Han.son. Harold C, Ph.D., Wiidlijr Sf>rtiaii\i

Nixon, Chari ks M.. M.S., iVildlifr t.toloRist

OocHKAN. \V, \V.. Jr., B.S,, Awtxmtr Wildliff .Spntalist

Havf-Ra. Stepmkn p., Pri.D,, Awtuuilr IVitdlifr h(ologi\t

Larkin. RtiNAi.n P., Ph.D.. Awottalr Witdhlf hi olo^ixt

QiINF,. Doi'fii.As B,. Ph.D., Avsoiialr Riof)h\Mi i.\l

Warner. Richard E-. Pll.D.. Avuxinlf WiUHifr tUohtfinl

\Vf_stfmkier, Ronald I,.. M.S., .-{wotiatr W'lldhfr Emiogist

VV<MJD. SisANNH (.,. Ph.D., A\sutmtr ClirmiU
Burnett, C^hristophfr D., Ph.D.. Awi^taui W'lldUfr tcolof^txt

Han.sfn, Lonnif- p.. Ph.D.. Assi\tant IVildhfr ErotogiH
Robinson. Scoit K.. Ph.D., Av^.t'-t/itii M'jW/i/*- h(olo^i.\t

WiTMAM. JaMF-S H.. Ph.D.. Assistant IVildliff Sf)rtiali.\l

Bi'ilNFfiKEMPF, John K,, M.S.. Assotintr Supportwr StirnliU

Brown. Britf VV . Ph.D.. Assi.UanI Supportnr S( irnlisl

Dr/A\. Ronald K., Assnlanl Supportn-r Siirntisl

(.lirri v. David. M.S.. A\si\tanl Supportivr .Snentisl

HbRKtRT. Jamf_s R., M.S., Assistant .Supportivr Siirnltst

JacK-SON, Cynthia Ci,. B.A,, A.\si.\lant Supporlnr S< irntisl

JoNEi. Jon Martin, M.A.. A.y\istanl Supportivr Stifnti\l

Pool, Robert R,, B,S.. Assi.stanl Supportivr Surnlisl

SzAFONl, ROBF.RT t.. M.S., As.u.stanl Supportivr Siirntisl

CRfLMinoN. RoBFRi !)., Junior Hroff.ssionat Sarttlnl
Sffts. Jamkn W.. Junior Proiessumal S( irntisl

.\ndfrson, F.i.i/abfth a., Srnmr Trt hnital Assistant

Bai'm. Sharon t., B.S.. Srnior Trihnnal Assnlnnl
Bf:i.<:hfk. H Kathi FFn. B.S.. SrnioT Tri tinual Assistant

HlNTFR. Kathf.rinf J.. Srnior Trthnital Assistant

Iko. William M.. B.S.. Tnlinunl Assistant

Martin. Brian H., B.S.. Tnhnual Assistant

Raim. Arlo J., M.S., Tfilinual Assistant

(;foR(.i, Michkllf:. Junior Trthniial AsM.stanI

RoAi, Katif. t.. Junior Trt hnical Axsistant

ADMINISTRATIVE UNIT
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Dl'/AN, PaiTY l... Word l*roie\sin^ Coordinator
HoDiiiNs. AlDRK^ S.. M.A,, Trthnual Editor

I.F Mfrf. I.IOYD, Teihnnal Hluslrator

Mc;C;LELr.AN, SiHRLFV. B.S., Assof latr Terhnual Editor

Stfgfr, Eva, B.A.. Assistant Teihnical Editor

Technical Library

IIflstfr. Carla, M.A., Trthmrat Librarian

I.tisK. Monica. /.jfrrnrv Trt finual Assistant

C:ONSl'l.rANTS AND RESEARCH AFFILIATES Aqualk Biology. RoafRT Costan/a. PhD . Frojrs.sor of Wrlland Etoloisy. Loui-

siana State t'niversily. Baton liounr: Bruce Hannon, Ph.D ,
I'lolr-Ksor of (ieoiirnph\. t'niversity of tUinois. Jamks R. Karr. Ph.D..

Hrofrssor of Etoltifiy. Ethology, and Ei-olution. I'ntversily of lUinois. Lewis L, Osborne. Ph.D., .Assistant I'rofrssor of I'rban and
Hr^iimal I'lanninii. I'nivrrsity of Illinois: John A. Iranqi'ILM, PhD,. He^ionnl Manai^rr. l)ut ks I 'nlimitrd: i\ni] Gregory S. Whitf,
Ph.D., I'rofrssor of (.rnelus and Dn'riopntrnl. I'nivrrsity of Illinois; BotanY and Plant Pa(hologY> Jkan D. .Schoknecht, Ph.D.. Ass*,-

iiale l*ri>frs.sor of l.ife Siirnirs. Indiana State ('nwersily. Terrr Haute. Faunisiit Surveys and ln.sccl Idenlificaiion, Roderick R. Irwin.

B.A., Chita^o. Illinois: Wildlife Research. Nanc^ I. Bi'RLEY, Ph.D., Assoiiate Professor of EioUtffy. Etholotry. and Etoluliou. ( 'niversity

of Illinois: RoBjRT L. Jonfis, Ph.D.. I'rofrssor of Soil A/oirrn/oiry and Eiolu^y. I'nnersily of IHinois: Willjid D, KlimNli.i. Pii D.. /*r.;-

frssor of /.oology and Dirntor of (:oof>erative Wildtifr Researth. Southern Illinois I'nnersily: .hkI Norman D. Levink, Ph.D.. Pro-

fessor of I'rtrrinary f*arasiloloicv. I'elerinary Rrsran h. and Zoology, .iiid Dim lor of the Crnler for Human EioUi^s. I'nivrrsily of Illi-

nois: Enlomology, Nelda Alge:r, Ph.D., Assmiate professor of (•enrlus and Prvrlopmrnl. t 'nn-rrsily of lllinms: Robert I.. NIftcai.f.

Ph.D.. I'rofrssor of Biology and Hr.seardi Professor of Enloinoloizy . i'mversity of Illinois: and Gn bfrt P Waidbai fB, Pii O ,
/'f'>-

frMor of Entomology. I'nivrr.Mly of Illinois.

(48.816—3M—8-85)



Some Publications of the ILLINOIS NATURAL HISTORY SURVEY

BULLETIN

Volume 33, Article 1.— Dipiera, or True Flies, of

Illinois. I. Tabanidae. L. L. Pechuman, Donald

W. Webb, and H. J. Teskey. April 1983. 122 p.

\'<)lume 33, Article 2.—An Annotated Bibliog-

raphy of the Illinois Herpelological Literature

1960-1980, and An Updated Ciheiklist of

.Species of the State. Michael A. Morris, Richard

.S. Funk, and Philip W. .Smith, April 1983. 15 p.

Volume 33, Article 3.— 12.') Years of Biological

Research 1958-1983: A Symposium. George

Godfrey, Chairman; John Bouseman, William

Edwards. Kenneth Robertson, and Robert

Zewadski, eds., Proceedings of the 125th An-

niversary Symposium of the Natural History

Survey. 1985. 200 p.

BIOLOGICAL NOTES

120.— Recreational Fishing in the Kankakee

River. Illinois, Robert J. Graham, R. Weldon
Larimore, and William F. Dimond. June 1984.

13 p.

121.— Bibliography of Illinois Vegetation. Paul

C;. Risser. August 198-1. 51 p.

122.—The Life History of the Mud Darter,

Elheosloma asjjrigptie, in Lake Greek, Illinois.

Kevin S. Gummings, James M. Grady, and

Brooks M. Burr. Decemliei 1984. 16 p.

123.—The Life History of the Shorthead Red-

horse. Moxosloma miurolrpidolitin. in the

Kankakee River Drainage. Illinois. .Michael J.

Sulc and Thomas M. Skelly. 1985. 16 p.

124.— Illinois Birds: Vireos. Jean W. Graber.

Richard R. Graber. and Ethelyn Kirk. 1985.

52 p.

SPECIAL PUBLICATION

Number 2.—Landsca|)e Ecology: Directions and
Approaches. Paul G. Risser. James R. Karr.

and Richard T. F. F'orman. November 1984.

18 p.

CIRCULAR

49.—The Dunesland Heritage of Illinois. Her-

bert H. Ross. August 1963 (Reprinted .Mav

1974). 28 p.

51.— Illinois Trees: Selection, Planting, and
Citre. J. Cedric Carter. March 1977 (Third

printing). 123 p.

52.— F'ertiliiing and Watering Tiees. Dan Neely
and E. B. Himelick. Decemln-r 1971 (Third

printing). 20 p.

54.—Corn Rootvvoiin Management in Ciinning
Sweet Corn. W. H. Luckmann. J. T. Shaw,
D. E. Kuhlman. R. Randell. and G. D. LeSar.

March 1975. 10 p.

55.—Observing. Photographing, and Collecting

Plants. Kenneth R. Robertson. August 1980.

62 p.

MANUSCRIPTS
High (|ualily manuscripts dealing with any aspect of natural history will be considered for publi-

cation ill one of the Illinois Natural History .Survey publication series: Bulletin, Binlogiral S'olrs.

Circular, and Spr< ml fublicalion. I'he author need not be an employee of the Survey, but if not. will

be required to pay priming costs. Manuscripts must follow the reccmimendations of the third edition

of the Council of Biology t'.ditors Style Manual except that journal namc-s in the Liteiature Citi-d

section are to be s|)elled out in full. Fhe Survey expects to publish only one or two manuscripts by

non-Survey authors yearly.

Two or more outside referees reconnnend each manuscript submitted for publiralion in ihc^BuI-

letin series before it is accepted.

Please send three copies of manuscripts to Ix- considered for publication to Office of the Chief,

Illinois Natural History Survey, 607 East Peabody Drive, ("hampaign, Illinois 61820.

/,/.v( oj available publications mailed on request

No charge is made for publications of the Illinois Natliral History Survey. A single copy of

most ptd)lications will be sent free to anyone requesting it until the supply becomes low. Cx)sily pub-

lications, more than one copy of a pid)licati<in, and pid)lications in shoii supply aie subjects for s|)ecial

correspondence. Such toriespondence should identify the writei and explain the use to Ik- made n(

the publications.

Address orders and corivspondence to (he Chief,

Illinois Natural History .Survey

Natural Resources Building

607 East Peabody Drive,

Champaign, Illinois 61820