SMALL MAMMALS (INSECTIVORA, LAGOMORPHA, AND RODENTIA) FROM THE EARLY PLEISTOCENE (IRVINGTONIAN) LEISEY SHELL PIT LOCAL FAUNA, HILLSBOROUGH COUNTY, FLORIDA Gary S. Morgant and John A. White2 ABSTRACT Twelve species of small mammals, including one species of Insectivora, two species of Lagomorpha, and nine species of Rodentia, are reported from the early Pleistocene (early Irvingtonian) Lcisey Shell Pit Local Fauna, Hillsborough County, Florida Most taxa of small mammals are rare in the Leisey fauna. The most common species is the sigmodontine rodent Sigmodon hbitinus, followed in abundance by the hydrochaerid Neochoerus sp., the arvicoline Pedomys sp., the soricid Blarina cf. B. carolinensis, the geornyid Geomys pinens, the giant castorid Castoroides leiseyorum, the erethizontid Erethizon dorsa,um, and the leporid Sylvilagus flondanus. Four undescribed species of rodents occur at Leisey, three of which, the arvicolines Pedomys and Synaptomys sp. and the large peromyscine Podomys sp., are represented by insufficient material for formal description. Castoroides leiseyorum is described as a new species that dilRrs from the Rancholabrean C. ohioensis in the absence of a mesopterygoid fossa. but is similar to lhe latter in size and most other morphological characters. Biochronological analysis of the rodents and lagomorphs from Leisey indicates a late early Irvingtonian age, probably between 1.3 and 1.0 Ma. C. teiseyorum, S. libitinus, and the undescribed species of Pedomys, Synaptomys, and Podomys are known only from Florida late early Irvingtonian faunas. The records of S. floridanus, G. pineris, and E. dorsatum from Leisey are among the oldest occurrences of these extant species. Other Florida small mammal faunas similar in age to LAisey are Haile 164 Haile 214 and Payne Creek Mine. Correlative early Irvingtonian faunas from western North America include: Gilliland, Texas; Holloman, Oklahoma; Kentuck and Watheng Kansas; Salpa, Nebraska; and Java, South Dakota l The senior author is a Paleontologist at the New Mexico Museum of Natuial History, 1801 Mountain Road NW, Albuquerque NM 87104- 1375, U.S A. (formerly a Senior Biological Sciences at the Florida Museum of Natural History, University of Florida, P. O. Box 117800, ~ainesville FL 32611-7800) The junior author is an Adjunct Professor in the Department of Geosciences, University of Anzona, Tucson AZ 85721, USA. MORGAN, G. S., and J. A WHITE. 1995. Small Mammals (Insectivora, l.agomorpha, and Rodentia from the Early Pleistocene (Irvingtonian) 12isey Shell Pit Lncal Fauna, Hillsborough County, Florida. Bull. Florida Mus. Nat. Hist 37 PL II(13):397-461. 398 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PT. IL NO. RESUMEN Desde la f~una local del dep6sito de conchuelas de kisey, condado de Hillsborough, Florida, se repotan doce especies de mimiferos pequ,*w incluy-t" una f=r=ie del orden 1,-,4,vora. dos especies de Lagomorpha y nueve especies de Rodentia provenientes del Pleistoceno temprano (In,ingtoniano temprano) Lamayoria de los taxonos de pequeaos mamiferosson rarosen la fauna de Lcisey. La especie mAs comOn es el roedor sigmod,5ntido Sigmodon libinnus, seguido en abundancia por el hydrochaido Neochoerus sp., el arvicalino Pedomys sp, el sodddo Blarina cf. B. carolinensis, el goomydo Geomys pinetis, el ca2160do gigpme Castoroides leiseyorum. el erethiz6raido Erethizon dorsatum. y el lep6tido Sylvilagus jloridanus. En LEisey existen cuatro ®species de rocdores no descritos, tres de los cuales. los anicolinos Pedomys y Synaptomys sp. y el gran peromyscino Podomys sp., se encuentran repr ' ' por ' - . .Al como para permitir una adecuada descripci~ Castoroldes le,sounim se describe como una nueva especie que difiere del Rancholabreano C., '' ' . · carecer . I. , afin cuando se asemeja a la primera en tamaao y en la mayoria de los caracteres mo1f616gices. Anati~,s biocronolbgicos de roedores y lagomorfos provenientes de Lcisey indican una edad Irvingtoniana lemprana tardia. probablemente de entre 1.3 y 1.0 Ma. C leueyorum, S. libitinus, y la especies no descritas de Pedomys, Synaptomys y Podomys se conocen desde falinss Irvingtonianas tempranas tardias en Florida. Los registros de S. ./londanus, G. pinens y E. dorsatum provenientes de LEisey se encuentran dentro de los mb antiguos para estas esl,ecies actualmente existenta Otras faunas de pequeaos mamiferos de Florida similarcs en edad a I£isey son Haile 164 Haile 21A y la Mina Payne Creek Las siguicntes son faunas correlativas al Irvingtoniano temprano del oeste de Norte Am6rica: Gilliland, Texas; Holloman, Oklahoma; Kentuck y Wathena, Kansas; Sat,pa, Nebraska; y Java, Dakota del Sur. INTRODUCTION The small mammal fauna from the Leisey Shell Pit is composed of 12 species belonging to the orders Insectivog Lagomorpha, and Rodentia. The term "small mammals" as used here refers to those orders of mammals typically consisting of species of small body size, although two of the rodents in the Leisey fauna are hardly small. The giant beaver Castoroides was bear-sized by some estimates and the extinct capybara Neochoerus was larger than the largest living rodent, the capybara hydrochaeris. The remainder of the small mammgls in the Leisey Shell Pit LF are indeed small in body size (less than 5 kg). Two other orders of small mammals commonly found in Florida Pleistocene vertebrate faunas, the Chiroptera and Marsupialia, are absent from Leisey. The Leisey Shell Pit Local Fauna (LF) includes vertebrate fossils collected from early Pleistocene sediments of the Bermont Formation in two large, nearly contiguous shell pits located less than 1 km inland from Tampa Bay about 7 km southwest of Ruskin, Hillsborough County, Florida. These two shell pits, owned by the Leisey Shell Corporation, were designated Leisey 1 and Leisey 3 by Hulbert and Morgan (1989). Specific collecting localities within the Leisey pits are designated by letters (e.g. Leisey 14 Leisey 34 etc.). A third pit, Leisey 2, contains primarily Rancholabrean vertebrates and is thus excluded from this analysis. Hulbert and Morgan (1989) and Morgan and Hulbert (this volume) MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 399 provided maps, coordinates, stratigraphic sections, and other information for the individual Leisey Shell Pit sites. These two papers should be consulted for more detailed geologic and geographic data. Small mammals are one of the most poorly represented groups of vertebrates in the Leisey Shell Pit LF. The Leisey small mammal fauna includes one species of insectivore, two lagomorphs, and nine rodents. Both the species diversity and abundance of small mammals at Leisey are low compared to several other well known Florida Irvingtonian sites. The most abundant species, the extinct cotton rat Sigmodon libitinus, is represented by more than 50 specimens. However, half of the species of small mammals from Leisey are known from fewer than five specimens. Of the two richest Leisey Shell Pit localities, Leisey lA and Leisey 34 the largest sample of microvertebrates is from Leisey 3A. Leisey lA yielded remarkable samples of ungulates, ground sloths, and large carnivores, but few terrestrial microvertebrates (Hulbert and Morgan 1989; Webb et al. 1989). The rarity of small mammals in the Leisey Shell Pit LF is not primarily a result of collecting bias since field crews from the Florida Museum of Natural History screenwashed and sorted over 1 metric ton of matrix from the bone-bearing layers in the Leisey lA and 3A sites. The hypothesizcd shallow· marine or estuarine depositional environment and accompanying taphonomic factors apparently had an adverse affect on the sampling and preservation of small mammals in the Leisey sites (Pratt and Hulbert this volume). Other small terrestrial vertebrates such as lizards, snakes, and passerine birds are also uncommon in the Leisey Shell Pit LF (see papers by Meylan and Emslie elsewhere in this volume). Florida has a wealth of Irvingtonian vertebrate faunas (Morgan and Hulbert this volume), but only a few of these have been thoroughly analyzed. The three best known Irvingtonian vertebrate faunas from Florida prior to the discovery of Leisey are all rich in small mammals, including the earliest Irvingtonian Inglis lA LF in Citrus County (Webb 1974; Kurt6n and Anderson 1980; Webb and Wilkins 1984; Morgan 1991), the early Irvingtonian Haile 16A LF in Alachua County (Ray et al. 1981; Morgan et al. 1988; Morgan 1991), and the late Irvingtonian Coleman 2A LF in Sumter County (Martin 1974; Kurt6n and Anderson 1980). These three faunas occur as cave or fissure fillings in the extensive karst terrain of northern penins,112r Florida. Morgan and Hulbert (this volume) provide synopses of the mammalian faunas from Inglis 14 Haile 164 and Coleman 2A, including both large and small mammals. With the exception of Martin's (1974) comprehensive analysis of the Coleman 2A LF and a preliminary faunal list for Inglis lA (Webb and Wilkins 1984), most previous studies on Florida Irvingtonian small mammals have consisted of reviews of selected taxonomic groups. The abundant insectivores, lagomorphs, and rodents in the Inglis 14 Haile 164 and Coleman 2A sites are very useful for purposes of comparison with the more limited micromammal fauna from Leisey. 400 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Pr. IL NO. ACKNOWLEDGEMENTS We are particularly grateful to the many avocational pateontologista. including D. J. Bethea, Ralph -rony' Estevez. Frank A Garcia. John Mitter, James L Pendergraft. and James Rans on, who donated important specimens of small mammals from Lcisey to the Florida Museum of Natural History Vertebrate Paleontology Collection. We thank Steven D. Emslie and Richard C. Hulbelt Jr., for their field assistance in the Lcisey screenwaghing effort David Lambert and S. David Webb helped collect sediments for screenwashing from Lcisey 3A. Arthur R. Poycr sorted the majority ofthe fossiliferous matrix from the two Leiscy sites. For helpful comments on the manuscript we thank Richard C. Hulbert Jr., Robeit A Mastin, and Ann E. Pratt Linda D. Chandler skillfully executed the drawings in Figure 6. Richard C. Hulbert Jr., assisted with Figure 7. This is University of Florida Contribution to Paleobiology Number 424. METHODS AND ABBREV[AT[ONS Responsibility for the three orders of small niammals from Lciscy was divided between the authors with GSM covering the Insectivora and Rodentia and JAW writing the section on L.agomorpha. Measurements are in mm and were taken with either dial calipers (accurate to 0.1 mm) or a Gaertner measuring microscope (accurate to 0.01). All Leisey specimens described here are housed in the Vertebrate Paleontology Collection ofthe Florida Museum of Natural History, University of Florida, Gainesville. More complete information on the various fossil localities discussed in the text including field notcs. detailed map data, photographs, etc. are available in the vert¢brate paleontology locality files of the Florida Museum of Natural History. Abbreviations used in the text are as follows: UP Florida Museum ofNatural History, University ofFlorida (formerly the Florida State Museum) 15 Incal Fauna NALMA North American Land Mammal Age Ma Mega-anna=millions of years before present ka kilo-anna=thousands ofyears before present MNI Minimum number of individuals P/p Upper/lower premolar (e* P# is the fourth upper premolar) Wm Upper/lower molar (e.i ml is the first lower molar) CHRONOLOGY Because we discuss the biochronology of the small mammals from Leisey and other Florida Irvingtonian sites in some detail, the chronology of the Pleistocene Epoch and the Irvingtonian Land Mammal Age are briefly summarized (see more extensive discussion in Morgan and Hulbert this volume). The boundaries and subdivisions of the Pleistocene follow Berggren et al. (1985) and Harland et al. MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 401 (1990). The Pliocene/Pleistocene boundary is placed at 1.64 Ma slightly above the top of the Olduvai Normal Subchron of the Matuyama Chron. The Pleistocene is subdivided into the early, middle, and late Pleistocene. The early Pleistocene begins at 1.64 Ma and ends at the boundary between the Matuyama and Brunhes chrons at 0.78 Ma. The middle Pleistocene covers the interval from the beginning of the Brunhes Chron at 0.78 Ma until the onset of the last (Sangamonian) interglacial at 130 ka. The late Pleistocene covers the period between 130 and 10 ka. The late Pliocene and Pleistocene incorporate three North American Land Mammal Ages: Blancan, Irvingtonian, and Rancholabrean. We follow the definitions and subdivisions of these three NALMA proposed by Lundelius et al. (1987). The Leisey Shell Pit LF is Irvingtonian in age and accordingly this NALMA will be our primaq focus; however, we also discuss taxa of small mammals from the late Blancan and Rancholabrean. The Blancan/Dvingtonian boundary is placed at about 1.9 Ma, while the Imingtonian/Rancholabrean boundary is about 0.3 Ma. The Blancan is entirely within the Pliocene covering the time period hom 4.5 to 1.9 Ma. Early and middle Blancan land mammal faunas are unknown from Florida. Two late Blancan sites (between 2.5 and 1.9 Ma) containing small mammals have been reported from the state, the Haile 15A LF in Alachua County (Robertson 1976) and the Macasphalt Shell Pit LF in Sarasota County (Morgan and Ridgway 1987). The Irvinglonian covers the latest Pliocene and much of the Pleistocene (between 1.9 and 0.3 Ma), and therefore it is useful to subdivide this NALMA into smaller units. Lundelius et al. (1987) recognized three subages of the Irvingtonian: early Irvingtonian (Sappan), middle Irvingtonian (Cudahyan), and late Irvingtonian (Sheridanian). The boundaries between the three Irvingtonian subdivisions are not well defined, but their approximate age ranges are as follows: early Irvingtonian (1.9-1.0 Ma); middle Irvingtonian (1.0-0.6 Ma); late Iivingtonian (0.6-0.3 Ma). The early Imingtonian covers nearly a million years and transcends the Pliocene-Pleistocene boundary. Accordingly, this time period is informally subdivided into the earliest Irvingtonian (1.9-1.6 Ma, latest Pliocene) and the late early Irvingtonian (1.6-1.0 Ma early Pleistocene). The Rancholabrean begins about 300 ka and ends at the Pleistocene/Holocene boundary at 10 ka. The boundary between the early Rancholabrean (300 ka-130 ka) and the late Rancholabrean (130-10 ka) approximates the beginning of the last (Sangamonian) interglacial high sea level stand. Repenning (1980; 1987) and L. D. Mamn (1979) both proposed biochronologies for the Blancan through the Rancholabrean NALMA based on evolutionary stages and immigration events of arvicoline or microtine rodents. The Irvingtonian I and Irvingtonian II of Repenning (1987) are more or less equivalent to the early and middle Irvingtonian, respectively, as defined above. However, the Rancholabrean I of Repenning (1987), is essentially the same as the late Irvingtonian recognized here and by Lundeliuk et al. (1987). 402 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, rr. IL NO. A mammalian biochronology that uses many different tan of both small and large mammals (e.g. Lundelius et al. 1987) is more applicable to Florida Plio- Pleistocene faunas than a scheme based solely on arvicoline rodents, which are generally rare in Florida. Many species of mammals characteristic of western and Api)alachian Irvingtonian sites are absent from Florida, whereas many Florida Irvingtonian mammals are unknown from faunas outside the state. Martin (1974, fig. 3.17) presented a chart showing the temporal distribution of selected Florida Plio-Pleistocene mammals, including both small and large taxa. Based on data from many new sites, Morgan and Hulbert (this volume) compiled a comprehensive biochronology of Florida Plio-Pleistocene mammals. A synopsis of their biochronology concentrating on Irvingtonian small mammals is provided in the Discussion section. SYSTEMATIC PALEONTOLOGY Order INSECTIVORA Bowdich 1821 Family SORICIDAE Gray 1821 Blarina cf. B. carolinensis Bachman 1831) Refemd Specimens.-Leisey 3A: UF 124335, left mandible with ml; UF 124336, edentulous left mandible; UF 132069, posterior half of edentulous left mandible. MNI=3. Description.-Three fragmentary mandibles are the only specimens of insectivores from the Leisey Shell Pit LF. All three mandibles are considerably larger than the least shrew, Coptotis parva, and are similar in size to modern mandibles of the short-tailed shrew, Blarina carolinensis, from the Florida peninsula. The single soricid ml from Leisey (UF 124335) is also similar in morphological characters and size (Table 1) to modern and fossil Florida specimens of B. caro/inensis. However, two slight differences were noted; the Leisey ml seems to have a somewhat more anteroposteriorly compressed talonid basin and the entoconid is more posteriorly placed. Table 1 includes ml measurements (total length and trigonid length) of one Blancan, four Irvingtonian, and two extant samples of Blarina from Florida. The modern samples include two subspecies, B. c. carolinensis from Citrus County in the northern half of the Florida peninsula and B. carolinensis peninsulae from Highlands County in the southern peninsula. Irvingtonian Blarina samples consist of specimens from the earliest Irvingtonian Inglis lA LF, the early Irvingtonian Haile 16A LF, Leisey Shell Pit, and the late Irvingtonian Coleman 2A LF. Jones et al. (1984) examined and measured the fossil Blarina mandibles from Inglis lA and MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 403 Table t. Dental meagurements (in mm) of Blancan, Irvingtonian, and modern Blarina from Florida. Mean observed range, and sample size, respectively. an provided for samples larger than one individual. Locality Age Lcngth of Length of ml ml trigonid Haile 15A late Blancan 1.5 1.0 d. Blarina UF 17466 Inglis 1 A earliest Irvingtonian 1.8 1.2 B. cf. B. carolinensis 1 .7- 1 .9 1 .2 N=5 N=5 Haile 16A early trving~onian 1.6 1.0 B. cf. B. carolinensia 1 . 5- 1 .7 0 .9- 1 . 1 N=11 N=11 Leisey 3 A early Irvingtonian B. cf. B. carolinenals UF 124333 1.55 1.0 Coleman 2A late In•ingtonian B. cf. B. carolinensis UF 11626 1.8 1.2 Citrus County Recent 1.6 1.0 B. c. carolinensis 1 .5- 1 .7 0.9-1 . 1 N=10 N=10 Highlands County Recent 1.7 1.1 B. c. peninsulae 1 .6- 1 .8 1 .0- 1 .2 N=10 N=10 Coleman 24 both of which they referred to B. carolinensis. The three Leisey shrew mandibles, and in particular the m 1 (UF 124335), are viMually identical in size and morphological features to the sample of Blarina from Haile 16A. The mls from Leisey and Haile 16A are within the range of B. c. carolinensis from northern Florida (Table 1). The Leisey shrews are tentatively referred to B. carohnensis based on their overall similarity in morphology and size to modern Florida samples of that species. The Inglis and Coleman Blarina, as well as extant B. carolinensis peninsulae, are larger than theLdsey specimens. 404 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PT. 4 NO. Remarks.-Until recently almost all extant Blarina from eastern North America were placed in the species B. brevicauda. Jones et al. (1984) demonstrated that B. brevicauda actually consists of at least three different species. B. carolinensis is the living representative of this genus in the southeastern United States. Jones et al. (1984) provided measurements of a large series of Blarina from throughout eastern North America which showed that B. carolinensis peninsulae from southern peninsular Florida is the smallest living subspecies of North American Blarina. However, our measurements of a sample of B. c. carohnensis from Citrus County in northern Florida averaged slightly smaller than a sample of B. c. peninsulae from Hightands County in southern Florida (Table 1). Despite these slight inconsistencies, the overall small size of Florida B. carolinensis is clearly established. The systematics of the late Blancan and Irvingtonian shrews from Florida cannot be properly addressed here, owing to the fragmentary condition of the three Lcisey soricid specimens. Robertson (1976) reported a mandible of Coptotis parva (UF 17466) from the late Blancan Haile 15A LF in Alachua County. He stated that this specimen was indistinguishable from modern Florida specimens of C. parva, except for its slightly larger size. However, the Haile 15A shrew has an unreduced talonid on m3, a character of Blarina (Repenning 1967), and the ml is similar in size to mls of extant B. carolinensis and fossils from Leisey and Haile 16A (see Table 1). The key to understanding the evolutionary history of Florida Plio-Pleistocene shrews lies in a detailed analysis of the large soricid samples from Inglis lA and Haile 164 both ofwhich possess a small and a large species. Other early Irvingtonian records of B. carolinensis, in addition to those from Florida include specimens from Wathena, Kansas and Java South Dakota. Both of these localities are outside the present range of this species (Jones et al. 1984). Middle Irvingtonian records of B. carolinensis from Cumberland Cave, Mafyland and Hanover Quarry, Pennsylvania are also well outside the current southeastern range of B. carolinensis. Order LAGOMORPHA Brandt 1855 Family LEPORIDAE Gray 1821 Sylvilagus floridanus (Allen 1890) Referred Specimens.-Leisey 3A: UF 96220, partial right mandible with p3; UF 96221, left p3. MNI=1. Tentatively Refemd Specimens.-Leisey lA: UF 83120, right and left premaxillae with left Il and right I2; UF 131997, right Il; UF 87965, two associated upper cheek teeth; UF 131996, upper cheek tooth; UF 131995, associated left I 1 and two upper cheek teeth; UF 86229, scapula; UF 88035, 131994, distal humeri (2); UF 87966, proximal radius; UF 87963, proximal ulna; MORGAN & WHITE: RODENTIA FROM LEISEY SHELL Prr 405 UF 81131, distal tibia; UF 85320, calcaneum; Leisey 3: UF 102666, distal humerus; UF 102667, femur. MNI=2. Description.-Among the leporid specimens from Leisey only the p35 are described and compared in detail, as other teeth and postcranial elements of both Sylvilagus and Lepus are generally considered to be nondiagnostic (White 199la). Two p35 from Leisey 3A are similar in size to the p3 of sy/vilagus floridanus, S. audubonii, S. transitionalis, and Lepus americanus. The measurements of the Leisey Sy/vilagus p35 are: UF 96220, length 3,1, width 3.0; UF 96221, length 3.0, width 2.5. The enamel pattern of these two teeth most closely resembles that of the p3 of S floridanus in the presence of a single anterior reentrant, the lack of folding of the thick enamel on the anterior edge of the posteroexternal reentrant, and minimal folding of the thin enamel on the posterior edge of this reentrant (Fig. lA). The Leisey p3s differ from S. bachmani and S. nuttallii by their larger size, from S. aquaticus, S. palustris, and S. cunicularius by smaRer size, and from S. brasiliensis by the lack of multiple anterior reentrants. The mcently described S webbi (White 199lb) from the late Blancan and early Irvingtonian of Florida differs from the Leisey p35 in larger size, greater number of anterior reentrants, and more complex enamel folding. The Leisey specimens are referred to S. floridanus based on the similarity in size and enamel pattern of p3. Remarks.-Leporids are notoriously difficult to identify from most cranial, dental, and postcranial remains. Paleontologists studying this family have tended to base their systematic conclusions on the structure of the p3, and to a lesser extent the P2 (e.g. White 19914b). The identification of Sylvilagus jloridanus from the Leisey Shell Pit is based on two p3s from Leisey 3A. The referral of the additional teeth and postcranial elements from Leisey lA and Leisey 3 to this species is based entirely on their small size, and therefore these identifications should be considered tentative. The first Sylvilagus to appear in the Florida fossil record is S. webbi from the late Blancan Macasphalt Shell Pit and Kissimmee River local faunas. S. webbi also occurs in the earliest Irvingtonian Inglis lA and De Soto Shell Pit local faunas and the late early Irvingtonian Haile 16A. Records of S. floridanus from Leisey and the correlative early Irvingtonian Payne Creek Mine and Haile 21A local faunas represent the earliest occurrence of this living species in Florida. The oldest records of S. floridanus are from the earliest Iivingtonian Curtis Ranch LF, Arizona and Vallecito Creek LF, California (White 199la). Hibbard and Dalquest (1966) reported Sy/vilagus cf, S, floridanus from the late early Irvingtonian Gilliland LF in Texas, a close correlative of Leisey based on the large mammal fauna (Morgan and Hulbert this volume). 406 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Pr. 4 NO. 1 1 ~:1.-.:0:}161 1 F5 C Figure 1. (A) Sylvitagus/Iondanus, Leisey 34 right p3 (reversed), UF 96220; (B) Lepus cf. L townsendli, Leiscy 14 left p3, UF 82165; (C) Geomy, pine#s, Leisey 1 4 left P4, UF 87225. Scale bar 1 mm in length for A and B and 2 mm in length fp C. Lepus cf. L. townsendii Bachman 1839 Refemd Specimen.-Leisey lA: UF 82165, left mandible with p3-p4. MNI=1. Tentatively Referred Specimens.-Leisey lA: UF 83659, distal humerus; UF 131992, partial innominate; UF 131993, distal femur. Description.-The Leisey Lepus p3 can be distinguished from Sy/vilagus aquaticus, S. palustris, and S. cunicularius by the single, slightly incised anterior reentrant and from all other species of Sy/vilagus by its larger size (Fig. 18). Measurements of the single p3 of Lepus (UF 82165) from Leisey are: length 3.5, MORGAN & WHrrE: RODENTIA FROM LEISEY SHELL PIT 407 width 3.1. The Leisey tooth can be distinguished from Lepus californicus, L. alleni, L. callotis, and L. jlavigularis by Uie slghtly indsed antedor reentrant from L. mnericanus by the posteroexternal reentrant which extends to the lingual border of p3, and from L. aUeni, L. arcticus, and L. othus by being smaller in size, falling below the observed ranges of the latter. The Leisey p3 is tentatively referred to Lepus townsendii because it more closely resembles that species than other members of the genus. However, there are two features in which the Leisey tooth differs from extant L. townsendii. The anterior external reentrant on the Leisey p3 is slightly less well incised than in any of the 22 modern specimens ofL. townsendii used for comparison. Also, Figure lB shows that on UF 82165 from I,eisey, the thin enamel on the posterior edge of the posteroexternal reentrant is moderately crenulated or folded. White (199la) noted that this thin enamel was typically folded in L. californicus and unfolded in L. townsendii. The Leisey tooth differs from L. californicus and the extinct species L. benjamini from the early Irvingtonian Anita LF in Arizona (Hay 1921) by its shallower anterior reentrant and less complicated enamel. The Leisey Lepus is smaller than L. giganteus from the middle Irvingtonian Conard Fissure LF in Arkansas (Brown 1908). The Leisey p3 differs from a large sample of Lepus p35 from the Inglis lA LF in its smaller size, particularly the width. The Leisey and Inglis p3s are similar in having both the anterior reentrant and anteroexternal reentrant weakly incised. The thin enamel on the posterior edge of the posteroexternal reentrant ranges from simple and unfolded in some Inglis specimens to moderately crenulated in other Inglis specimens and the Leisey tooth. Further study of the Inglis sample may reveal that an undescribed species is present in Florida Irvingtonian faunas, but for now the Inglis jackrabbits are identified only as Lepus sp.. Both the Inglis 1 A and Coleman 2A Lepus have been referred to L. alleni (see Martin 1974; Webb and Wilkins 1984). However, the p35 of the Inglis lA Lepus can be distinguished from L. alleni by the weakly incised anterior reentrant and the lack of highly folded enamel. The Lepus sample from Coleman 2A consists entirely of postcranials (Martin 1974). Remarks.-The identification of Lepus cf. L. townsendii from Leisey is based on a mandible with p3 -p4. The three postcranial elements are tentatively referred to this species on the basis of their very large size compared to other leporid postcranials from Leisey. Lepus was first reported from Florida in the Coleman 2A and Inglis lA Irvingtonian faunas (Martin 1974). Previously unreported specimens of Lepus from Florida include a femur from the middle Irvingtonian McLeod LF in Levy County and an edentulous mandibular symphysis (UF 128991) from the late early Irvinglonian Payne Creek Mine. The fossil record indicates that in Florida Lepus is restricted to the Imingtonian. The white-tailed jackrabbit Lepus townsendii is an extant species found on the Great Plains as far east as Illinois. Although Lundelius et al (1987) used the first 408 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr. IL NO. 1 appearance of the genus Lepus as one of the defining taxa for the Irvingtonian NALMA, Lepus is now known from at least two very late Blancan faunas, Big Springs, Nebraska and Borchers, Kansas (White 199la). White noted that both of these faunas contained some p35 that resembled L. townsendii and others that were more similar to L. californicus. This is very reminiscent of the sample of Lepus p35 from the Inglis lA LF. Inglis is only slightly younger than Big Springs and Borchers, and represents the earliest record of Lepus in Florida. Order RODENTIA Bowdich 1821 Family GEOMYIDAE Gill 1872 Geomyspinetis Rines,tue 1806 Referred Specimens.-Leisey lA: UF 87225, partial right and left maxillae with left P4; UF 80044, 87964, right Il (2); UF 88031, len Il; UF 125202, left mandible with il, p#-m2; UF 83625, left mandible with p4; UF 81827, left il; UF 83829, distal humerus. Leisey 3A: UF 125208, proximal ulna. Leisey 3: UF 124564, right mandible with i 1, p4-m 1. MNI=3. Description.-Four specimens of Geomys from the Leisey Shell Pit LF, three from Leisey lA and one from Leisey 34 provide sufficient morphological information to permit an identification to the species level. A portion of the right and left maxillae with a P4 (UF 87225; Fig. IC) is pafticularly significant, as the P4 is perhaps the single most diagnostic tooth used to document the evolutionary history of Geomys during the late Pliocene and Pleistocene of Florida (Wilkins 1984). The Leisey P4 is comparatively large (anteroposterior length 2.3, width of posterior loph 2.4) and totally lacks enamel on its posterior surface. Wilkins (1984) did not provide measurements of the upper dentition of Florida fossil Geomys, and thus no comparative measurements of the P4 are presented here. One or more P45 of Geomys are known from three other Irvingtonian sites in Florida: Inglis 14 Haile 164 and Coleman 2A. Wilkins (1984) stated that the Geomys from Inglis lA and Haile 16A possessed enamet on at least half up to the entire posterior surface of P4, while specimens from Coleman 24 as well as extant G. pinetis, lacked enamel in this region. In an examination of the larger sample of Geomys now available from Haile 164 a wider range of variation was noted in the amount of enamel on the posterior surface of P4 than was observed by Wilkins (1984). Because of its taxonomic importance, this character was re-examined for all Florida Blancan and Irvingtonian Geomys. Among 20 randomly selected P4s of the extinct species G. propinetis (Wilkins 1984) from Inglis lA (out of a total sample of over 100), 15 teeth (75%) have from 50-100% coverage of enamel on the posterior surface, 4 teeth (20%) have less than 50% coverage. and.on 1 tooth the enamel is almost absent (coverage less than 5%, but still perceptible). The entire sample of 16 P4s MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 409 of G. propinetis from Haile 16A was examined, of which only 4 teeth (25%) have 50-100% enamel coverage on the posterior surface, 7 teeth (44%) have less than 50% coverage, and in 5 teeth (31%) the enamel coverage is nearly to totally absent. Two P4s of Geomys (UF 100342, 104493) from the late Blancan Macasphalt Shell Pit LF in Sarasota County, Florida were examined as well. Both of these teeth are very similar to the majority of specimens of G. propinetis from Inglis lA in having nearly total coverage of enamel on their posterior surface. The single Geomys P4 from Leisey and a sample of six P4s from Coleman 2A resemble modern G. pinetis in lacking enamel on their posterior surface. The progressive loss of enamel on the posterior surface of P4 in Florida fossil Geomys from the late Pliocene and early Pleistocene provides a good indicator of age. G. propinetis from the late Blancan Macasphalt Shell Pit LF and the earliest Irvingtonian Inglis 1 A LF is characterized by having more than 50% of the posterior surface of P4 covered with enamel in most individuals, as well as by small size. Although the Geomys from Haile 16A is referred to G. propinetis following Wilkins (1984), the enamel on the posterior edge of P4 in this sample is reduced compared to the two older samples. More than half of the P45 from Haile 16A have less than 50% enamel coverage on the posterior surface, including two teeth in which enamel is completely absent. It is not surprising that the Haile 16A Geomys is somewhat advanced over the sample from Inglis lA, as other data suggest that the former site is younger. This character must have been evolving rapidly during the early Irvingtonian, because in the late early Irvingtonian Leisey Shell Pit LF, enamel was totally absent on the posterior surface of P4, a trait found in all younger samples referred to G. pinetis. P45 of G. pinetis from Leisey and Coleman 2A, as well as modern specimens of this species, are larger than those of G. propinetis from Haile 16A, Inglis lA, and Macasphalt. Another important evolutionary trend in Florida Geomys is the increasing size and depth of the retromolar fossa through time (Wilkins 1984). The retromolar fossa is a pit located on the dorsal surface of the mandible posterolabial to the m2 and m3, and lingual to the coronoid process. The increase in size of the retromolar fossa is evident in the increasing distance between the base of the coronoid process and the toothrow labial to m2 and m3. The retromolar fossa is short, narrow, and very shallow in the Inglis lA sample (Wilkins 1984). This fossa is noticeably longer and much deeper in modern G. pinetis, and in fossil mandibles referred to this species from Leisey and Coleman. The anterior edge of the retromolar fossa is located posterolabial to the m2 and forms a nearly vertical plate in G. pinetis, whereas the anterior margin slopes gradually posteriorly in mandibles of G. propinetis from Inglis. Although no mandibles from Haile 16A preserving the retromolar fossa were available to Wilkins for study, one mandible is now known from this site (UF 69117) that preserves the anterior half of the retromolar fossa. The complete length and depth of the retromolar fossa cannot be determined from this specimen, but enough of this structure is preserved to confirm that it is very shallow and has a gently sloping anterior margin as in the Inglis 410 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr. 4 NO. 1 mandibles. The Leisey and Coleman mandibles are similar to modern G. pinetis in the size and depth of the retromolar fossa. A third trend Wilkins (1984) observed in Florida Geomys was an increase in body size, using the observed range in width of the lower incisor as a size indicator. Although Wilkins (1984) noted that the width of il is dependent on the ontogenetic age of the individual, the maximum width of the il has increased through time. Only two lower incisors of Geomys are known from Leisey with widths of 1.7 and 2.2 mm (Table 2). Based on measurements in Wilkins (1984), this is slightly smaller than the maximum width of the il in modern G. pinetis (2.5 mm) and the range of lower incisor widths observed in the Coleman sample (1.9- 2.5 mm). The maximum width of the Leisey lower incisors is broader than the ils of G. propinetis from Inglis lA in which the maximum width is 1.9 mm (Wilkins 1984). Measurements of the two most complete mandibles of Geomys from Leisey are compared in Table 2 to mandibles from Haile 16A and Coleman 2A. Wilkins (1984) should be consulted for mandibular measurements of G. propinetis from Inglis lA and Recent G. pinetis. The measurements presented here and those of Wilkins (1984) indicate that the Leisey Geomys is intermediate in size between the smaller G. propinetis from Inglis lA and Haile 16A and the somewhat larger specimens of G. pinetis from Coleman 2A. The maximum size of modern G. pinetis apparently was achieved by the late Irvingtonian (Wilkins 1984). Remarks.-Pocket gophers of the genus Geomys are first recorded in Florida from the late Blancan Macasphalt Shell Pit and Haile 15A local faunas (Morgan and Ridgway 1987). Based on small size and presence of enamel on the posterior surface of P4, the Macasphalt sample is referred to G. propinetis, an extinct species originally described from the earliest Irvingtonian Inglis lA LF (Wilkins 1984). The Haile 15A Geomys sample lacks a P4, but does possess a single specimen of the diagnostic M3 (Wilkins 1984) that closely resembles the M3 of G. propinetis. A small sample of Geomys recently identified from the earliest Irvingtonian De Soto Shell Pit in De Soto County, a correlative of Inglis 14 lacks the P4, M3, and mandibles, but is tentatively referred to G. propinetis on the basis of small size and age. The Geomys sample from Haile 16A is referred to G. propinetis following Wilkins (1984), but is somewhat more advanced than the Inglis pocket gopher in characters of the P4 and slightly larger size. The Geomys sample from the Leisey Shell Pit LF possesses characters of the extant species, G. pinetis, including the lack of enamel on the posterior surface of P4 and a large, deep retromolar fossa on the mandible, but is somewhat smaller. The living southeastern pocket gopher, G. pinetis, first appears in Florida at Leisey, presumably having evolved in situ from G. propinetis during the early Irvingtonian. It is dimcult to correlate the Florida Irvingtonian Geomys with other North American pocket gophers belonging to this MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 411 Table 2. Measurements (in mm) of lower incisors and cheek teeth of selected Irvingtonian Geomys from Florida Description ofmeasurements follows Wilkins (1984). anterior postedor width length width width width 1*,cality il ,>4 ,}4 ,>4 mi Haile 16A UF 69116 1.7 2.5 1.4 2.0 2.0 UF 69117 1.9 2.8 1.7 2.1 - IEisey Shell Pit UF 125202 2.2 2.7 1.8 2.5 2.3 UF 125564 1.7 2.7 1.5 2.2 2.2 UF 83625 - 2.7 1.5 2.2 - Coleman 2A UF 45861 2.5 2.8 1.7 2.4 2.6 UF 45864 2.2 2.9 1.6 2.3 2.4 UF 15001 - 2.9 1.9 2.5 - genus because fossils of both G. propinetis and G. pinetis are restricted to Florida (Wilkins 1984). The extant species G. pinetis has a rather limited distribution as well, occurring only in Florida, Georgia, and Alabama. Family CASTORIDAE Gray 1821 Cas#oroides leiseyorum new species Holotype.-UF 81736, posterior half of skull from Leisey Shell Pit 14 Hillsborough County, Florida Bermont Formation, late early Irvingtonian. Collected by Frank A. Garcia in August 1984. Paratypes.-UF 60868, posterior half of skull from Leisey 1, collected by Frank A. Garcia in 1983; UF 115965, left mandible with il, p4-m3 from Leisey 3, collected by Ralph Estevez and John Miller on 30 March 1988. Refemd Specimens.--kisey IA: UF 66000, incisor fragment; UF 83119, 86862, astragalus (2). Leisey 3B: UF 132047, partial cheektooth; Leisey 3: UF 124563, partial cheektooth. MNI=3. 412 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL- 37, Fr. II, NO. 1 Diagnosis.-Castoroides leiseyorum can be differentiated from C ohioensis, the only other currently recognized species in the genus, by the absence of a mesopterygoid fossa on the basisphenoid. In C /eiseyorum, the basisphenoid bears a shallow elongated groove in the anatomical position where the deeply concave, ovate mesopterygoid fossa is located in C. ohioensis. C leiseyorum can also be separated from C ohioensis by characters of the lambdoidal crest. In C. leiseyorum this crest is lower and more rounded, and in dorsal view is strongly convex posterolaterally with a deep V-shaped identation along the midline where it meets the sagittal crest. The lambdoidal crest is higher and sharper in C. ohioensis, and in dorsal view is more nearly parallel to the posterior margin of the skull. C. leiseyorum canbe distingdshed from Procastoroides sweeti by its larger size and the presence of well-developed longitudin~ ridges and grooves on the incisors. C leiseprum differs from P. idahoensis in its larger size and by the presence of isolated enamel laminae on all lower cheek teeth resulting from the absence of enamel at the labial termination of the paranexid and mesoflexid and the lingual termination of the hypoflexid. Etymology.-Named for Bud Leisey and members of his family, as well as for the employees of the Leisey Shell Corporation. The study of paleontology in Florida has benefitted immeasurably from their cooperation and generosity. Description.-The mandible and two braincases of Castoroides from Lcisey are the most complete fossils of the giant beaver yet found in Florida. A nearly perfect left mandible (UF 115965) has a complete dentition, including an intact lower incisor. The mandibular ramus is virtually complete, with the exception of the coronoid process, the posterolateral portion of the capsular process, the posteriormost extremity of the angular process, and a portion of the ventral margin external to the incisor (Figs. 2A-C). The two partial skulls are nearly intact posterior to the interorbital constriction. The mandible of Castoroides leiseyorum from Leisey was directly compared with specimens of C ohioensis from various Florida Rancholabrean sites and with published descriptions, figures, and measurements of other complete mandibles of C ohioensis from elsewhere in eastern North America. The Leisey mandible also was compared to literature descriptions and figures of the two Blancan tan of giant beavers, Procastoroides sweeti (Barbour and Schultz 1937; Woodburne 1961) and P. idahoensis (Shotwell 1970). Like C ohioensis, the lower incisor of the C /eiseyorum is strongly ridged or crenulated. The p4 of C. leiseyorum is vety similar to that of typical C ohioensis from the Rancholabrcan. In both of these forms the paraflexid, mesoflexid, and hypoflexid extend entirely across the tooth from the labial to the lingual margin thereby completely isolating the four lophids as complete enamel laminae (dental terminology for castorid teeth follows Woodburne 1961). The mesoflexid and hypoflexid are also complete on the ml- MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 413 W. C Z Figure 2. Castoroides leiseyorum new species. Leisey 3, left mandible with i 1, p4-n13 (paratype), UF 115965. (A) lateral view; (B) medial view, (C) dorsal view. Scale bar 30 mm in length- 414 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PT. IL NO. 1 Table 3. Measurements (in mm) ofthe lower dentition of Castoroides and Procastoroides. Abbreviations are: L (length) and W (width). Mean observed range, and sample size, respectively, are provided fbr all samples. except the single Lcisey specimen. Species alveolar occlud length leng& L A t p4-00 p+In3 il il Procaatorides sweeti 50.3 11 .5 10.4 12.3 Blancan 50-51 10.6-12.8 9.6-12.0 9.2-14.2 Kansasl N=3 N=4 N=4 N=13 Procastoroides idahoensis 60.5 - 14.9 14.8 14.9 Blancan - - - 14.6-15.1 Idah02 N=l N=l N=1 N=3 Castoroides leiseyorum Leisey Shell Pit UF 115965 73.2 69.6 23.3 20.8 22.1 Castoroides ohioen~ 6% 61 24.9 20.3 19.5 Florida - - 22.4-29.3 18.6-21.6 14.6-24.5 N=1 N=1 N=7 N=7 N==6 Castoroides ohioensis - 71 .0 23.6 20.8 19.5 (exclusiw of Florida)~ 70-72 20-27 20-22 19-20 N=2 N=5 N=5 N=2 1 Measurements Rom Woodbtune 0961) 2 Measurements Rom Shotwe[1 (1970) m3 and isolate the three lophids on each of these teeth. Furthermore, the enamel on the labial margin of the lophids is thin on all four cheekteeth of C leiseyorum, especially on the labial edge of the median lophid. The lower cheekteeth of the Leisey mandible are similar in size to those of C ohioensis from the Rancholabrean (Table 3). There appear to be no obvious differences between C leiseyorum and C ohioensis in the lower dentition and mandibular ramus. Shotwell (1970) described the species Procastoroides idahoensis from the late Blancan Grand View LF in Idaho. Unlike the earlier Blancan species, P. sweeti, P. idahoensis has well developed longitudinal ridges on the incisors, like Castoroides. P. idahoensis is distinguished from Castoroides primarily by its smaller size, but also by the tendency for enamel to be present at the labial termination of the paraflexid and mesoflexid and lingual termination of the hypoflexid on the p4. MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 415 Table 3 Extended. LWLWLW ml ml m2 n12 m3 m3 6 1,£ 11.4 9.3 11.1 8.9 9.8 8.2 8.3-11.3 10.2-13.0 7.6-10.2 9.5-12.3 7.8-10.0 9.0-11.0 6.6-9.2 N=13 N=7 N=7 N=9 N="9 N==3 N=5 11.3 12.0 13.1 11.4 10.9 10.8-11.7 - - - - N=3 N=1 N=1 N=1 N=1 16.4 16.6 13.9 17.3 14.1 18.8 12.8 15.5 16.5 13.7 15.8 14.6 13.5 12.9 13.4-17.4 16.4-16.6 12.5-14.9 - - N=6 N=2 N=2 N=1 N=l N=1 N=1 14.0 16.5 14.5 17.0 14.0 16 12 12-16 16-17 13-16 17 13-15 - - N=2 N=2 N=2 N=2 N=2 N=1 N=1 3 Meas=nantm Rom Hay (1914) Ind Ba,bas (1931). These terminations are composed of much thinner enamel than on the remainder of the tooth. In certain p45 of P. idahoensis, including the type, the paraflexid, mesoft exid. and hypoftexid extend entirely across the tooth as in Castoroides. The ml from the type of P. idahoensis also has isolated enamel lophids like the p4; however, on the m2 of this specimen the medial and posterior lophids are connected by enamel at the lingual termination of the hypoflexid (Shotwell 1970). All of the lophids are isolated as complete enamel laminae on the four lower cheekteeth of the C leiseyorum mandible. Martin (1969) described an extinct subspecies of Castoroides, C ohioensis dilophidus, from the Rancholabrean Santa Fe River 2 locality in northern peningular Florida. This subspecies is characterized by the division of the 2nd anterior lophid on the p4 into two isolated elliptical enamel laminae. In C. ohioensis from elsewhere in North America boththe 1st and 2nd anterior lophids 416 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37. FT. II, NO. 1 on p4 are undivided, consisting of single laminae. The single p4 of C leiseyorum lacks the divided 2nd anterior lophid, and thus has the typical morphology of C ohioensis. The two braincases of Castoroides leiseyorum from Leisey (Figs. 3-4) provide much information on the posterior half of the skull. Stirton (1965) published excellent descriptions and figures of the skull of C ohioensis. Detailed morphological comparisons were made between the two Leisey skulls and the figures and descriptions of C ohioensis from Stirton. Cranial measurements are provided for the two skulls of C. leiseyorum (Table 4), and where possible, these are compared to measurements of five of the most complete skulls of late Pleistocene C ohioensis (from Stirton 1965:276). Barbour and Schultz (1937, fig. 2) figured the holotype skull of Procastoroides sweeti from the Broadwater LF in Nebraska in dorsal and lateral views, and provided a very brief morphological description. They presented five cranial measurements for P. sweeti; however, most of these were based on a nearly complete skull (total length, zygomatic breadth. etc.), and thus cannot be compared to the incomplete Leisey skulls. Martin and Schultz (1985) figured and described a braincase of P. idahoensis from the late Blancan Seneca LF of Nebraska, but provided no measurements. In most features of the braincase, Castoroides kiseyorum does not appear to differ significantly from C ohioensis. Likewise. almost every one of the measurements taken on the two Leisey skulls (Table 4) is within the range of variation of the five C ohioensis skulls measured by Stirton (1965). Many authors (e.g. Hay 1914; Stirton 1965) have noted that Castoroides is unique in possessing two separate posterior openings for the internal nares, one dorsal and one ventral. The posterodorsal opening, termed the mesopterygoid fossa by Stirton (1965), is perhaps the most unusual cranial feature of Castoroides, consisting of a large, deep fossa in the basisphenoid. The mesopterygoid fossa is ovate in outline, very deep, and opens anterodorsally into the internal narial passage. The ventral floor of this fossa is formed by expanded processes of the pterygoids. In a skull of C ohioensis from McClean County, Illinois described by Stirton (1965). the mesopterygoid fossa is 23.0 mm in length and 15.8 mm in width. In another skull of C. ohioensis from Logansport, Indiana this opening is 25 mm long and 16 mm wide (Hay 1914). Surprisingly, the dorsal mesopterygoid fossa. which is so characteristic of Castoroides ohioensis, is completely absent in the two braincases of C leiseyorum, both of which have reasonably complete basicranial regions (Figs. 3B, 4B). In the two Leisey skulls, the basisphenoid is well preserved and it lacks the large, deep, ovate fossa for the posterodorsal opening of the internal narial passage. Instead the basisphenoid in C /eiseyorum bears a slightly concave, elongated groove along the midline. This groove connects anteriorly to the internal narial opening in the paratype skull (UF 60868), although that portion of the basicranial region anterior to the basisphenoid is absent in the holotype (UF 81736). Both Leisey skulls are MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 417 A i... 4. 14 1 *48'DE'/swpl.- :4. -9rl:"lilic ¢ tx ' X 'X l X 1 1 X X X Sylvilagus webbi T X - - - Sylvitagus palustris - X - Sylvilagudondanus XXX I X t x X X x 1% ix 1 x x :x x B U LLE TIN FLO R ID A M U SEU M N ATU R A L H IS TO R Y V O L 37, F r. IL N O . 13 Sylvilagus *. Glaucomys sp. x3 Sciurus carohnensis X X - Castoroides leiseyorum - - T Geomys propinetis T X - - - Geomys pinetis X X X Thomomys orientalis Zapus Sp. - Erethizon kleini T - - - Erethizon dorsatum X X X Neochoerus sp X Hydrochaeris holmesi X Neotoma sp. X Ochrotomys nuttalli - Peromy,cus small sp.4 X - - - X X X ix ix i X Podomys floridanua - > < 1 X X I I X I X il IE - 1 M O RG AN & W HITE: RO DENTIA FRO M LEISEY SHELL PIT 447 Re#hrodontongs sp. X Reithrodontomys humulis - Sigmodon cunisi X Sigmodon minor - - - - I I I I X I I X I I X X I X I I X l I " X 1 X X ' 1 Sigmodon libitimis - T X X X - Sigmodon bakeri X- Atopomys salwlimis - X - Neofiber leonardi - X - Neofiber allent - X Ondatra idahoensis X - - Ondatro annectens - - X Pedomys new * - T - X X - Pitymys aratal - Synaptomy, p. - X 41 . .... ' ' ' ' 11, and therefore is elm06: certality incomplete. 27kL,p.i,Som/01=1=2Aandinglis IA U 1 - ... - ' ' . " 7 ' 1974. Webb and Wilkins 1984). however, theLepwmandibles from lnglis are notL. a#eni end the Coleman sample kle the 84;nostic pl 1rhe Inglis IA Glaucom),isanewspecies ciurently being described by k E. Pratt . V ... 80:1*11.. /ndp.polion.hu 4.romy,cu'luge ap. is a large species m the sizz range of P. cu=60,~a,id.n,i, 404-, ap. appears to be a new spemel thatis la,Be than P.»fdamu. 448 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr. IL NO. 1 bats in these three sites, in particular a species of Myotis, indicates deposition in a cave environment. Morgan and Hulbert (this volume) review the Irvingtonian vertebrate faunas presently known from Florida. Their paper and the references cited therein should be consulted for more complete data on the location geology, and vertebrate faunas from these sites. Table 8 shows the occurrence and chronological distribution of the 40 species of Insectivog Lagomorpha, and Rodentia currently known from eight Florida Irvingtonian sites. This table does not include all Iningtonian faunas from Florida, only those with five or more species of small mammals. Several other Florida Irvinglonian sites containing diagnostic specimens of rodents (e.g. Apollo Beach) are briefly discussed at the end of this section. The Marsupialia and Chiroptera are not included in Table 8 because these two orders are absent at Leisey. The following are synopses of the small mammal fan-< from the Florida Irvingtonian sites listed in Table 8. Each of these faunas is compared and contrasted with Leisey. Inglis 14 Citrus County.-Inglis lA has the richest small mammal fauna of any Florida Irvingtonian site, although many of the taxa have not been thoroughly studied. A preliminary list of the mammals from Inglis lA has been published (Webb 1974; Webb and Wilkins 1984). Morgan (1991) briefly discussed the rich chiropteran fauna from Inglis lA. The Inglis small mammals include 24 species: three species of insectivores, seven bats, three lagomorphs, and eleven rodents. Leisey shares eight of its twelve genera of small mammals with Inglis lA. Among the four Leisey genera absent from Inglis 14 Castoroides, Pedomys, and Synaptomys are biochronologically significant since their earliest records appear to be in late early Imingtonian sites such as Leisey. Leisey and Inglis share at most two species of small mammals, and even these are questionable. Five taxa of small mammals from these two sites are congeneric but differ at the species level (Inglis species firstfLeisey spedes secondly. Geomys propinetis/G. pinetis; Erethizon kleini/E. dorsatum; Sigmodon curtisi/S. libitinus, Ondatra idahoensisiO. annectens, and Sylvilagus webbilS.floridanus. Inglis IA shares G. propinetis and S. webbi with several Florida late Blancan faunas. 0. idahoensis is found in latest Blancan and earliest Irvingtonian faunas in western North America. S. curtisi appears to be restricted to the earliest Irvingtonian. The best estimate for the age of the Inglis lA LF based on both small and large mammals is earliest Imingtonian (latest Pliocene) between 1.9 and 1.6 Ma. De Soto Shell Pit, De Soto County.-The De Soto Shell Pit has a limited although quite interesting, small mammal fauna. This site actually possessed an abundance of microvertebrates, but the pit filled with water before UF crews were able to conduct extensive screenwashing operations there. The De Soto Shell Pit LF includes 12 species of small mammals: one species of insectivore, one bat, one rabbit, and nine rodents. The De Soto and Leisey 3A sites apparently formed MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 449 under similar depositional conditions. Both have large samples of aquatic vertebrates, including freshwater and estuarine tan, along with a less diverse fauna of terrestrial microvertebrates. The De Soto Shell Pit LF has a number of genera but very few species of small mammals in common with Leisey. De Soto and Inglis lA share four species of biochronologically diagnostic small mammals: Geomys propinetis, Sigmodon curtisi, Ondatra idahoensis, and Sylvilagus webbi. None of these species occur at Leisey. 0. idahoensis and S. curtisi appear to be restricted to earliest Irvingtonian faunas in Florida. De Soto is the only Florida locality in which the diminutive cotton rat, S. minor, occurs. This species is otherwise known only from faunas in the western United States. S minor has been synonymi~d with the Blancan S medius by several authors (e. g. Martin 1986). The two forms differ in size, as this lineage of Sigmodon underwent a dwarfing event sometime in the late Pliocene. The S minor teeth from De Soto are noticeably smaller than comparable Florida S medius teeth, and therefore we have chosen to tentatively regard them as separate species. The presence of the primitive arvicoline Atopomys salvelinus and a large undescribed Peromyscus (or possibly Podomys) suggests that the De Soto Shell Pit LF may be slightly younger than Inglis 14 although it is still earliest Irvingtonian in age. Haile 164 Alachua County.-Many of the small mammals from Haile 16A have been described in taxonomic studies on selected species, but Morgan and Hulbert (this volume) provide the only faunal list of mammals from this site. The small mammal fauna from Haile 16A consists of 17 species: three insectivores, two bats, one rabbit, and eleven rodents. Leisey and Haile 16A have eight genera and six species in common. Castoroides, Neochoerus, Ondatra, and Lepus are present at Leisey, but absent from Haile 16A. Species shared by these two faunas include: Blarina cf. B. carolinensis, Erethizon dorsatum, Sigmodon libitinus, and undescribed species of Podomys, Pedomys, and Synaptomys. The two genera in which the species from Hale 16A and Leisey differ at the species level are Geomys and Sylvitagus. The records of G. propinetis and S. webbi from Haile 16A are the youngest for these species, which otherwise are found in late Pliocene (late Blancan and earliest Irvingtonian) faunas in Florida. The occurrence of the larger and more evolutionarily advanced species G. pinetis at Leisey indicates this site is probably slightly younger than Haile 16A. Winkler and Grady (1990) reported Atopomys salvelinus from Haile 164 a species supposedly characteristic of middle Irvingtonian faunas. Although its biochronological significance is unknown, the only known Florida occurrence of the zapodid rodent Zapus is from Haile 16A. The Haile 16A Zapus represents the southernmost known sample of this genus. It differs in several dental features from the extant eastern species, Z. hudsonius. Overall, Haile 16A and Leisey have very similar small mammal faunas suggesting that the two sites are close in age, with Haile 16A probably slightly older. Haile 16A has been regarded as middle Irvingtonian by most previous authors (Frazier 1981; Morgan et al 1988; Winkler and Gra* 1990; Morgan 1991), 430 BULIlmN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PT. IL NO. 1 although Lundelius et al. (1987) questionably placed this fauna in the late Irvingtonian. The small mammal fauna suggests that an early Irvingtonian age is more likely. Four species of mammals from Haile 16A indicate that this site is older than Leisey. Three of these are Blancan holdovers in which this site represents their youngest known occurrence. However, Haile 16A has more species in common with Leisey and other late early Irvingtonian sites. The faunal evidence suggests that Haile 16A falls in the middle third of the early Irvingtonian (between 1.6 and 1.3 Ma), younger Inglis lA and De Soto Shell Pit and slightly older than Leisey Shell Pit Payne Creek Mine, Polk County.-The small mammals from the Payne Creek Mine LF have not been mentioned previously in the literature. The ten species of small mammals identified from this site are listed in Table 8, including two insectivores, three rabbits, and five rodents. Among these tan, all but Scalopus aquaticus and */vilagus palustris are shared with Leisey. Furthermore, at least five of the species in common between these two faunas are good biochronologic indicators. Among these five species, Sigmodon libitinus, Ondatra annectens, and an undescribed species of Pedomys are limited to the late early Irvingtonian in Florida. The presence of Sylvilagus floridanus and Geomys pinetis at Payne Creek and Leisey, as well as S. palustris from Payne Creek, represent the earliest records of these species in Florida. Comparisons of both small and large mammals suggest that the Payne Creek Mine LF is closest in age to Leisey among currently known Forida Irvingtonian faunas. Haile 214 Alachua County.-Haile 21A has a rather limited small mammal fauna composed of seven species, including two bats, a rabbit, and four rodents. This site shares three species with Leisey and Payne Creek Mine, Sylvilagus floridanus, Geomys pinetis, and Sigmodon libitinus. The first two of these are living species that appear during the latter half of the early Irvingtonian, while S. libitinus is restricted to the Florida early Irvingtonian. McI,eod Limerock Mine, Levy County.-Several taxa of small mammals are known from the McLeod LF even though this site was discovered in 1941 before the advent of extensive screenwashing. McLeod is the only major Florida Irvingtonian site not housed in the UF vertebrate paleontology collection, and as a consequence we did not have the opportunity to examine the small mammals from this fauna. We are grateful to Richard Hulbert and Robert Martin for providing preliminary identifications of several taxa of McLeod rodents. Only four species from McLeod are listed in Table 8, two rabbits and two rodents, although we strongly suspect that other tan of small mammals are present in this fauna but have not yet been identified. The only small mammal previously reported from McLeod is the extinct round-tailed muskrat Neofiber leonardi (Frazier 1977), representing the sole record of this species in Florida. Other localities in western MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 451 North America where N. leonardi is known to occur, including Rezabek (type locality) and Kanopolis in Kansas and Slaton in Texas, are generally considered late Irvingtonian. Martin (pen. comm.) has tentatively identified Sigmodon bakeri from McLeod. This Florida endemic is known from the Coleman 2A LF, as well as several early Rancholabrean sites. Although both diagnostic small mammals identified from McLeod seem to suggest a late Imingtonian age, this site is clearly older than Coleman 2A. Several large mammals from this site, including Smilodon gracilis (see Berta 1987) and Tapirus haysii (see Hulbert this volume), are more typical of middle Irvingtonian faunas. McLeod is probably late middle Irvingtonian in age (0.7-0.6 Ma), although an early late Ilvingtonian age is also possible. Coleman 24 Sumter County.-The most thoroughly studied small mammal fauna from the Irvingtonian of Florida is Coleman 2A (Martin 1974). The small mammals from Coleman 2A consist of 23 species, including three insectivores, three bats, two lagomorphs, fourteen rodents, and the opossum Didelphis vi,giniana (Martin 1974). Among the twelve genera of small mammals recorded from the Leisey Shell Pit LF, only Castoroides, Ondatra, and Synaptomys are absent from Coleman 2A (Table 8). Of the nine genera shared by Leisey and Coleman, at least four appear to differ at the species level, further substantiating the disparity in age between between these two sites indicated by the large mammals (Morgan and Hulbert this volume). Sigmodon hbifinus occurs at Leisey, while the species, S. bakeri is found at Coleman 2A (Martin 1974,1979). Leisey has an undescribed species of Pedomys, while Pitymys aratai is known only from Coleman 2A. Measurements of Blarina from Leisey and Coleman indicate that specimens from the latter site are somewhat larger, but the systematic and/or biochronologic significance of this difference is unknown. Coleman 2A represents the earliest fossil record of five species of small mammals otherwise restricted to the Rancholabrean and Recent, including Dide/phis virginiana, Neojiber alleni, Ochrotomys nuttalli, Podomys jloridanus, and Reithrodontomys humulis. The presence of thebear Arctodus pristinus and the wolf Canis armbrusteri at Coleman 2A substantiate an Irvingtonian age, as does the absence of Bison. The occurrence of S. bakeri in several early Rancholabrean faunas and the appearance of several extant species of small mammals strongly suggests that Coleman 2A is latest Irvingtonian in age probably between 0.4 and 0.3 Ma (Martin 1974). Other Florida Irvingtonian Sites.--Several species of rodents are known from other Florida Irvingtonian faunas, in addition to the eight sites listed in Table 8 and discussed above. Erethizon dorsatum (see Frazier 1981) and Neochoerus (see Ahearn 1981) have been reported from Apollo Beach in Hillsborough County. The extinctporcupine E kieini was recorded from the Merritt Island LF in Brevard County of probable early Irvingtonian age (Frazier 1981). Other previously unpublished records of Irvingtonian rodents from Florida include Castoroides from 452 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr. II, NO. 1 Apollo Beach and the Crystal River Power Plant, Ondatra annectens from Pool Branch and Sigmodon libitinus from the Shell Materials Pit Biochronology of Florida Irvingtonian Small Mammals Comparisons of the Insectivorg Lagomorpha. and Rodentia from the eight most diverse Florida Irvingtonian sites (see Table 8) reveal an important biochronologic sequence of faunas that generally reflects the ages indicated by the large mammals (see discussion in Morgan and Hulbert this volume). Certain lineages of rodents and rabbits (e.g. Geomys, Sigmodon, Ondatra, Pedomys, */vilagus) are useful in providing a subdivision of the Florida Irvingtonian. Figure 7 shows the known biochronologic ranges of 31 species of lagomorphs and rodents in the late Pliocene and Pleistocene of Florida. Small mammals restricted to the Blancan or Rancholabrean are included in Figure 7, although species from these two NALMA are not discussed in detail. The following are biochronological characterizations of the small mammal faunas from the five Irvingtonian subdivisions recognized here. A well documented biochronological framework such as that proposed here and by Morgan and Hulbert (this volume) is of obvious utility in a state where many sites occur in karst-derived deposits that are not amenable to more standard geochronologic methods such as lithostratigraphy, radioisotopic dating, and paleomagnetic stratigraphy. Earliest Irvinatonian ( 1.9 to 1.6 Ma). Two Florida earliest Irvingtonian sites contain small mammal faunas, Inglis lA and De Soto Shell Pit. The Forsberg Shell Pit in Charlotte County (Morgan and Hulbert this volume) appears to be of this same age, but so far has produced only a limited fauna of larger mammals. Four species of rodents are restricted to earliest Irvingtonian faunas in Florida: Erethizon kleini, Sigmodon curtisi, S. minor, and Ondatra idahoensis. However, both S. minor and O. idahoensis occur in late Blancan faunas in the western United States. Two other species found in Inglis lA and De Soto Shell Pit, Sylvilagus webbi and Geomys propinetis, also occur in Florida late Blancan faunas, as well as the early Irvingtonian Haile 16A LF. The record of Atopomys salvelinus from the De Soto Shell Pit represents the earliest occurrence of this genus. Notable absences from Florida earliest Irvingtonian faunas are Costoroides, Pedomys, and Synaptomys, all ofwhich appear during the late early Ilvingtonian. Late early Irvinatonian ( 1.6 to 1.0 Ma). Florida sites of late early Irvingtonian age possessing diagnostic small mammal faunas are Haile 164 Leisey Shell Pit, Payne Creek Mine, and Haile 21A. Correlative faunas with few or no species of small mammals, but which have diagnostic tan of larger mammals, include Apollo Beach, Crystal River Power Plant, Pool Branch, Punti MORGAN & WHrrE: RODENTIA FROM LEISEY SHELL PIT 453 ,I,Iilll,lil,lil,I,I,I,I,Iib PLIOCENE PLEISTOCENE i early I middle Bate A LATE IRVINGTONIAN EN BLANCAN *2 AG E N ALM A BIO C H R O N O LO G IC RANG ES O F FLO R ID A PLIO -PLEISTO C EN E LAG O M O R PH A AN D R O D EN TIA :9 earliest I late early I middle I late earlyllate \ Sylvilagus webbi Sylvilagus palustris Sylvitagus floridanus ~ Castoroides leiseyonim Castoroides ohioensis \ M=v„.1. p..pinelis Gew„,„r.."-6 ) Ereth/zon n. sp. Erethizon kleini 1 Erethizon dor-1-, ---\Neochoerus dichroplax Neochoerus sp. ~ Neochoerus pinckeyi ~ \Sigmodon medius Sigmodon minor j Sigmodon curtial ~ Sigmodon libitinw Sigmodon bakeri Sigmodon hispidus ~Atopomys salvelinus Neofiber leonardi -~ Neofiber alleni \ Ondatra idahoensis Ondatra annectens \ Ondatra zibethicus Pitymys n . sp. 1 Pitymys aratai -4 Pitymys hibbardi - Pitymys pinetorum Synaptomys sp Synaptomys australis \ Figure 7. Biochronologic ranges of selected Rodentia and Lagomorpha from the late Pliocene and Pleistocene of Florida. PUymys n. sp. is the same species discussed in the text as Pedomys sp. 454 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Pr. IL NO. 13 Gorda, and Rigby Shell Pit (Morgan and Hulbert this volume). Six species of rodents are restricted to late early Irvingtonian faunas in Florida: Castoroides leiseyorum, Zapus sp., Sigmodon libitinus, Ondatra annectens, and undescdbed species of Pedomys and Synaptomys. Because Castoroides leiseyorum is currently known only from the Leisey Shell Pit, its biochronologic range is unknown. Records of Castoroides from Apollo Beach and the Crystal River Power Plant likely pertain to this species. S. libitinus is a Florida endemic, while 0. annectens occurs in both late early and middle Irvingtonian faunas in western North America. Florida late early In@gtonian faunas are further characterized by the first appearance of two living species of lagomorphs, Sy/vilagus «#oridanus and S. palustris, and two extant rodents, Geomys pinetis and Erethizon dorsatum. Hane 16A appears to be slightly older than other Florida late early Irvingtonian falinag based on the presence of Geomys propinetis and 5,/vilagus webbi. Haile 16A probably dates to the early half of the late early Irvingtonian ( 1.6 to 1.3 Ma), while Leisey Shell Pit Payne Creek Mine, and Haile 21A fall in the latter half (1.3 to 1.0 Ma). Middle Irvingtonian (1.0-0.6 Ma). Vertebrate faunas of middle Irvingtonian age are represented in Florida solely by the poorly known McLeod Limerock Mine LF in Levy County. Only two species of small mammals from McLeod are good biwhronological indicators, Neojiber leonardi and Sigmodon bakeri. N. leonardi is not known from other Florida Irvingtonian faunas (Frazier 1977), but occurs primarily in late Irvingtonian faunas elsewhere in North America S. bakeri is a Florida endemic previously reported from the late Irvingtonian Coleman 2A LF, as well as several early Rancholabrean sites. Although the two most diagnostic species of small mammals so far identified from McLeod are more typical of late Imingtonian faunas, several large mammals from this site are indicative of a middle Indngtonian age. The conflicting biochronological evidence from the small and large mammals suggests that McLeod probably falls either in the latter part of the middle Irvingtonian or the early part of the late Irvingtonian, between 0.7 and 0.5 Ma. Late Irvinatonian (0.6-0.3 Ma). The late Irvingtonian in Florida is represented by the Coleman 2A LF, unless the McLeod LF belongs in the early portion of this interval, in which case the biochronological ranges of several large mammals would have to be redefined. The only species that appears to be restricted to the late Irvingtonian in Florida is the extinct vote, Pi(pnys aratai. Sigmodon bakeri was originally described from Coleman 24 but has also been reported from the older McLeod LF and the younger early Rancholabrean Haile 74 Bradenton, and Williston 3A local faunas (Martin 1974; 1979). Coleman 2A represents the earliest fossil record for several species of small mammals otherwise restricted to the Rancholabrean and Recent, including Dide/phis vi,giniana, Ochrotomys nuttalli, Podomys Jloridanus, Reithrodontomys humulis, and Neojiber MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 455 a//eni. The only Irvingtonian record for the pocket gopher Thomomys orientalis is from Coleman 2A (Wilkins 1985). This extinct species is otherwise restricted to a few Florida Rancholabrean faunas (Simpson 1928; Wilkins 1985). Based on the large number of living tan, Martin (1974) suggested that Coleman 2A was latest Irvingtonian in age, probably between 0.4 and 0.3 Ma. Comparison of Leisey With Other North American Iningtonian Small Mammal Faunas There are no radiometric dates in direct association with any Florida Plio- Pleistocene vertebrate localities and the Leisey Shell Pit is the only Florida Ifvingtonian site with a known paleomagnetic signature (reversed-Matuyama Chron, see MacFadden this volume). The age of Leisey and other Florida Irvingtonian fannas must be determined primarily by biochronological comparisons with well-dated faunas from the western United States. However, the small mammals from Leisey are difficult to correlate with non-Florida Irvingtonian sites because of faunal provincialism (Lundelius et al 1987). The modern small mammals of Florida, particularly the rodents, consist mostly of species restricted to eastern North America, many of which are further limited to the southeastern United States. This regionalism was probably typical of the late Pliocene and Pleistocene as well, and thus it is not surprising that Florida Irvingtonian sites share few species with well known faunas of similar age from western North America. In eastern North America small mammal faunas representing the late Blancan and early Irvingtonian NALMA are currently known only from Florida. Several middle Irvingtonian (Irvingtonian II of Repenning 1987) small mammal faunas are recognized from the Appalachian region, including Cumberland Cave in Maryland, Hamilton Cave and Trout Cave in West Virginia, and Port Kennedy Cave in Pennsylvania (Kurt6n and Anderson 1980; Repenning and Grady 1988). As previously noted by Guilday (1971), there are only a Rw species of small mammals in common between Florida and Appalachian Irvingtonian faunas. Guilday (1971:235) stated that, "The ecological disparity between those areas [i.e. Florida and the Appalachians] is, and presumably was during the past, too great to support a common fauna." These faunal distinctions appear to be related to the contrasting climatic and biogeographic histories of the two regions. Florida Irvingtonian faunas have a strong Neotropical influence, while those from the Appalachian region have a predominance of north temperate and bored species. Despite these differences, we will concentrate on the taxonomic similarities between Florida Iwingtonian small mammal faunas and those from both the eastern and western United States. 456 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, PT. II. NO. 13 Arvicoline rodents have been used extensively in Plio-Pleistocene biochronology in North America. Both Repenning (1980;1987) and L. D. Martin (1979) proposed biochronologies for the North American Pliocene and Pleistocene based solely on arvicoline rodents. Among the large number of Irvingtonian arvicoline faunas discussed by Repenning (1987), only the middle Irvmgtonian (=Irvingtonian ID Cumberland Cave LF in Maryland is located in eastern North America. Repenning and Grady (1988) have since described an extensive middle Irvingtonian arvicoline fauna from Hamilton Cave, West Virginia. The published arvicoline fauna from the late Imingtonian Coleman 2A LF (Mamn 1974; Frazier 1977), which includes Neofiber al/eni and Piomys aratai, was not mentioned by Repenning (1987). Arvicolines are principally temperate and boreal rodents, and accordingly have a limited distribution in subtropical regions such as Florida. With only three species presently occurring in the state, Microtus pennsylvanicus, Piomys pinetorum, and Neo#ber a#eni, Florida has one of the poorest arvicoline faunas in the continental United States. Likewise, aivicoline rodents generally are uncommon in most Florida Pliocene and Pleistocene sites. Blancan faunas in the state lack arvicolines, whereas eight species of uvicolines occur in Florida Irvingtonian sites, including three from Leisey (Table 8). Martin and Schultz (1985) named the Sappan subprovincial age, typified by the Sappa LF of Nebraska, for a number of early Irvingtonian vertebrate faunas from the Great Plains. The Sappan is equivalent to the early Irvingtonian of Lundelius et al. (1987) and Morgan and Hulbert (this volume) and the Irvingtonian 1 of Repenning (1987). Martin and Schultz characterized Sappan faunas by the co-occurrence of Lepus, Allophaiomys, Mictomys kansasensis, Stegomastodon, Titanoo,lopus, and the first North American appearance of Mammuthus. The genera Mictomys, Stegomastodon, and Titanoodopus are unknown from Florida; however, Lepus and Mammuthus are present at Leisey. Leisey also shares the muskrat Ondatra annectens with many of these Sappan faunas. In addition to the Sappa LF, Sappan faunas include: the Java IS in South Dakota, the Kentuck, Nash, and Wathena local faunas in Kansas, the Holloman LF in Oklahoma, and the Gilliland LF in Texas (Hibbard and Dalquest 1966; Martin and Schultz 1985; Lundelius et al. 1987). Morgan and Hulbert (this volume) considered many of these same early Irvingtonian faunas to be close correlatives of Leisey based on their large mammal faunas, in particular, Gilliland and Holloman. Small mammals are rare in the Gilliland and Holloman local faunas, whereas most of the Sappan faunas from South Dakota, Nebraska, and Kansas have limited samples of large mammals. Radiometric dates are available for several of these sites. The Nash LF occurs between volcanic ash beds dated at 1.96 and 1.2 Ma (Eshelman and Hibbard 1981), while the Sappa LF occurs just beneath an ash dated at 1.2 Ma (Martin and Schultz 1985). The western Sappan faunas discussed above and the correlative faunas from Florida, including Leisey Shell Pit Haile 164 Payne Creek Mine, and Haile MORGAN & WHITE: RODENTIA FROM LEISEY SHELL Prr 457 21A among others, belong to the Pleistocene portion of the early Irvingtonian between 1.64 and 1.0 Ma. This is a rather long interval of time covering nearly two-thirds of a million years, thus allowing for a substantial range of ages among the included faunas. Earliest Irvingtonian (latest Pliocene) faunas are distinctly older than the Leisey Shell Pit LF based on differences in both the small and large mammals. Two Florida faunas are earliest Irvingtonian in age, Inglis lA and De Soto Shell Pit. Perhaps the most distinctive feature of these two faunas is the presence of Blancan holdovers, including the hyaenid Chasmaporthetes oss@agus, the mustelid Trigonictis macrodon, the antilocaprid Capromeryx arizonensis. and the dwarf Florida form of the ground sloth Megalonyx leptostomus, as well as Geomys propinetis and S>/vilagus webbi among small mammals. None of these species occur at Leisey. Trigonictis, G. pinetis, and S. webbi are also present in the Haile 16A LF, which is intermediate in age between the older Inglis and De Soto faunas and the younger Leisey fauna. Mammuthus is absent from earliest Irvingtonian faunas, as well as Haile 16A. Inglis and De Soto correlate most closely with the Curtis Ranch LF in Arizona, the Vallecito Creek LF in California, and the Wellsch Valley LF in Saskatchewan. Based on paleomagnetic polarity stratigraphy these three western earliest Irvingtonian faunas appear to fall either just before, within or just after the Olduvai Normal Subchron of the Matuyama Chron (Lundelius et al. 1987). The range ofages for these faunas is between 1.9 and 1.64 Ma, from the Blancanmvingtonian boundary to the beginning of the Pleistocene. Comparisons between Leisey and Irvingtonian sites from outside of Florida reveal certain similarities with middle Irvingtonian faunas (=Cudahyan of Lundelius et al. 1987 and Irvingtonian II of Repenning 1987). Typical western faunas of this age (1.0 to 0.6 Ma) include the Cudahy If in Kansas, Conard Fissure LF in Arkansas, and Vera LF in Texas. The Cudahy and Vera faunas both occur below ashes radiometrically dated at 0.61 Ma (Lundelius et al 1987). Several cave faunas from the Appalachian region have been regarded as middle Irvingtonian in age as well, the best known of which are Cumberland Cave, Port Kennedy Cave, Hamilton Cave, and Trout Cave (Kurt6n and Anderson 1980; Repenning and Grady 1988). None of the Appalachian Irvingtonian sites have absolute dates and their relative ages have been determined by biochronological comparisons. Repenning and Grady restricted the age of Hamilton Cave to between 0.85 and 0.74 Ma based on its extensive arvicoline fauna. Leisey shares only one alvicoline with Hamilton Cave, the muskrat Ondatra annectens, a long- ranging species typical of both late early and middle Irvingtonian faunas (late Irvingtonian I and Irvingtonian II of Repenning 1987). The primitive arvicoline Atopomys is not known from Leisey but is found in Haile 16A and De Soto Shell Pit. Although Atopomys is restricted to middle Irvingtonian faunas according to Winkler and Grady (1990), both Florida faunas containing this genus are early Irvingtonian. 458 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr.4 NO. 13 I.cisey also shares several species of large mammals with Port Kennedy Cave, Cumberland Cave, and Hamilton Cave. Four large carnivores, including the cheetah-like cal Miracinonyx inexpectatus, the sabercal Smilodon gracilis, the tremarctme bear Arctodus pristinus, and the wolf Canis armbrusteri, as well as the ground sloth Megalonyx wheatieyi, occur at Leisey and in one or more of these three Appalachian middle Irvingtonian cave deposits (Guilday 1971; McDonald 1977; Kurt6n and Anderson 1980; Van Valkenburgh et al. 1990). On the basis of mammalian biochronology, the Leisey Shell Pit LF correlates most closely with the latter half of the early Imingtonian between 1.3 and 1.0 Ma. Faunal criteria strongly suggest that Leisey is younger than earliest Irvingtonian faunas such as Inglis lA and De Soto Shell Pit (i.e. younger than about 1.6 Ma) and older than the late middle Irvingtonian McLeod Limerock Mine LF (i.e. older than 0.7 Ma). Biochronological data further restrict the age of Leisey to the latter half of the early In,inglonian. Geochronological data rule out an early middle Irvingtonian age (between about 1.0 and 0.78 Ma, see other papers in this volume by Morgan and Hulbert; Jones et al; and MacFadden). The similarity of Leisey to certain middle Irvingtonian vertebrate faunas suggests that it falls late:in the early Irvingtonian interval, and accordingly may be no more than several, hundred thousand years older than Cumberland Cave, Hamilton Cave, and Port Kennedy. LITERATURE CITED Aheam. M. A. 1981. A revision of'the North American Hydrochoeridae. M.S. Thesis, Univ. Florida Gainesville. . and J. F. Lance. 1980. A new species of Neochoerus (Rodentia: Hydrochoeridae) from the Blancan (late Pliocene) of Nodh America. Proc. Biol. Soc. Washington 93:435-442. Barbour, E. H. 1931. The giant beaver, Ca:toroides, and the common beaver, Castor, in Nebraska Nebraska State Mus., Bull. 20.1:171-186. -, and C. B. Schultz 1937. An carly Pleistocene fauna from Nebraska. Amer. Mus Nov. 942: 1-10. Berggren. W. A, D. V. Kent, 1 J. Fly:m, and J. A Van Couvering. 1985. Cenozoic geochronology. Geol. Soc. Amer. Bull. 96:1407-1418. Bala. A 1987. The sabrecat Smitodon gracms from Florida and a discussion of its relationships (Smilodontini, Felidae, Mammalia). Bull. Florida State Mus„ BioL Sci. 31(1):1-63. Bmwn, B. 1908. The Conard Fissure, a Pleistocene bone deposit in northern Astansas: with description of two new gencra and twenty new species of mammals. Mem Amer. Mus. Nat. Hist 9(4):157- 208. Carleton, M. D. 1980. Phylogenetic relationships in neotomine-peromyscine rodents (Muroidea) and a reappraisal ofthe dichotomy within New World Cricetinae. Mus. Zool., Univ. Michigan. Misc. Publ. 157:1-146. Eshelman, R. E., and C. W. Hibbard. 1981. Nash Local Fauna (Pleistocene: Aftonian) of Meade County, Kansas Contrib. Mus. Palm, Univ. Michigan 25(16):317-326. Frazier. M. K 1977. New records ofNeo#ber leonardi (Rodentia: Cricetidae) and the paleoecology ofthe genus. J. Mamm 58:368-373. . 1981. A revision of the fossil Erethizontidac of North America. Bull. Florida State Mus.. Biol. Sci. 27(1):1-76. MORGAN & WHITE: RODENTIA FROM LEISEY SHELL PIT 459 Guilday. J. E. 1971. The Pleistocenc history ofthe Appalachian mammal fauna. Pp 233-262 in P. C. Holt (ed.). The Distributional History of the Biota of the Southern Appalachiang, Part III: Vertebrates. Virginia Poly. Inst and State Univ., Res. Div. Monogr. 4: 1-306. . and C. 0. Handley. Jr. 1967. A new Peromy:cus (Rodentia. Cricetidae) from the Pleigtocene of Ma:yland. AIm Carnegie Mus. 39(6):91-103. Hall E. R. 1981. TIE mammals of North America. 2nd Ed„ 2 Vols. Jolm Wiley and Sons, New York. 1181 pp. Harland, W. B.. R L Arms:rong, A V. Cox, A G. Smith. and D. G. Smith 1990. A geologic time scale 1989. Cambridge Univ. Press. Cambridge. 263 pp. Hay, O. P. 1914. The Pleisto©ene mammals of Iowa. Iowa Geol. Surv., Ana Rep. 1912,23.1-662. 1921. Descriptions of species of Pleistocene vertebrata. types or sped- of which most are preserved in the United States National Museum. Proc. U. S. Natl Mus. 59(2391):599-642. Hibbard. C. W.. and W. W. Dalquest. 1966. Fossils Rom the Seymour Formation of Knox and Baylor Counties, Tms, and their bearing on the late Kansan climate of that region Contrib. Mus. Palma, Univ. Michigan 21(1).1-66. Hulbert, R. C., Jr., and O. S. Morgui 1989. Stratigraphy, paleoccology, and vertebrate fauna of the Leisey Shell Pit Ikcal Fauna, carly Pleistocene (Irvingtonian) of southwestern Florida. Pap. Florida Paleon. 21-19. - - and A R. Poyer. 1989. Ag.,riated skeletons ofmegathere, pampathere, tapir, and turtles from the latest Pliocene or earliest Pleigtocene of nortb-central Florida. J. Vert Paleon. 9(3, suppl.):26A Husson, A M. 1978. The mammals of Suriname. Zool. Monogr. Rijksmusem Nat Hist, Leiden, Netherlands 2:1-569. Jones, C. A, J. R. Choate, and H. H. Genoways. 1984. Phylogeny and paleobiogeography ofshort-tailed shrews (Genus Blarina). Pp. 56-148 m H. H. Genoways and M. R. Da,%804 eds. Contributions in Quaternary Vatebrate Paleontology A volume in Memorial to John E. Guilday. Carnegie Mus. Nat Hist. Spec. Publ. 8. Kurtan, B., and E. Anderson. 1980. Pleistocene Mammals of North America- Columbia Univ. Press, New York, 442 p. I.awrence, B. 1942. The muskrat in Florida. New England Zool. Club 19:17-20. I.undelius. E. L. Jr., C. S. Churcher, T. Dom* C. R. Harington, E. H. Lindsay, G. E. Schultz, H. A Semken. S. D. Webb. and R. J. Zakrzewski. 1987. The North American Quaternary sequence. Pp. 211-235 in M. O. Woodburne, ed. Cenozoic Mammals of North America. Geochronology and Biostratigraphy. Univ. California Press. Berkeley. Martin. L D. 1979. The biostratigraphy ofarvicoline rodents in North America Trans. Nebraska Acad- Sci. 7:91-100. 1989. Plio-Pleistocene rodents in North America Pp. 47-58 in C. C. Black and M. R. Dawson, eds. Papen on Fossil Rodents in Honor of Albed Elmer Wood. Nat. Hist Mus. Los Angeles Co., Sci. Ser. No. 33, 192 pp. . and C. B. Schultz 1985. Small manunals ofthe Seneca and Sappa local faunas (post-Ogallala of Nebraska). Inst Tertiary-Quaternary Stud-TER-QUA Symp. Ser. 1:163-179. Martin, R. A 1969. T y of the giant Pleistocene beaver Castoroides from Florida. J. Paleon. 43:1033-1041. . 1974. Fossil mammals from the Coleman IIA Fauna Sumter County. Pp. 35-99 in S. D. Webb, ed. Pleistocene Mammals of Florida. Univ. Presses Florida, Gainesville 1975. Giant Pleistoocne beavers and the Waccaassa River, kvy County, Florida. Bull. New Jersey Acad. Sci. 20:29-30. . 1979. Fossil history ofthe rodent genus Sigmodon. Evol. Monogr. 2:1-36. . 1986. Energy. eoology, andootton rat evolution Paleobiology 12:370-382. . 1987. Notes on the classification and evolution of some North American fossil Microtus (Mammalia: Rodentia). J. VerL Paleon. 7.270-283. 1989. Arvioolid rodents of the carly Pleistocene Java Local Fauna from north-central South Dakota. J. Vert Paleon. 9:438450. . 1993. Patterns of variation and speciation in Quaternary rodents Pp 226-280 in R. A. Martin and A D. Barnosky, eds Morphological Change m Quaterna,y Mammals of North America. Cambridge Univ. Press. Cambridge. 460 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 37, Fr. IL NO. 1 . In press. A new early Pleistocene species of Microtus (Pedomys) from the southern United States with comments on the taxonomy and early evolution of Pedomys in North America J. Vert Pateon. - and R. Tedesco. 1976. Ondatra annectens (Mammalia: Rodentia) from the Pleistocene Java Local Fauna ofSouth Dakota. J. Paleon. 50:846-850. McI)onald, H. G. 1977. Description of the outeology of the extinct gravigrade edentate Megaton,or, with observations on its ontogeny, phylogeny and functional.„.1.iny. M.S. Thesis. Univ. Florida Gainesville. Mona, A. 1984. Estudios sol)re la familia Hydrochocridae, XIV. Revision sistenitica. Senckenbergiana Biol. 65(1/2):1-17. , and J. Ojasti. 1986. Hydrochoerus hydrochaeris. Manm Spec. 264:1-7. Morgan. G. S. 1991. Neotropical Chiroptera from the Pliocene and Pleistocene of Florida. Bull. Amer. Mus. NaL }list 206:176-213. , O. J. Linares. and C. E. Ray. 1988. New species of fossil vampire bats (Mammalia: Chiroptera: Desmodontidac) from Florida and Venezuela. Proc. Biol. Soc. Washington 101:912-928. - and R. B. Ridgway. 1987. Late Plioccne (late Blancan) vellebrates f~om the St. Petersburg Times Site, Pinellas County, Florida, with a brief review of Florida Blancan faunas. Pap. Florida Pateon. 1.1-22 Neill, W. T., and R. P. Bullen. 1951 Muskral remains from a prchistoric Indian site in Jackson County, Florida. J. Manm 36:138. Nelson. R. S.. and H. A. Seniken. 1970. Paleoccological and stratigraphic significance of the muskrat in Pleistocene deposits. Geol. Soc. Amer. Bull. 81:3733-3738. Olsen, S. J. 1958. Thebog lemming fron, the Pleistocene of Florida. J. Mammal. 39:537-540. Ray, C. E. 1967. Pleistocene mammals from I.adds, Barlow County, Georgia. Bull. Georgia Acad. Sci. 25(3):120-150. , E. Anderson, and S. D. Webb. 1981. The Blancan carnivore Tngonictis (Mammalia: Mustelidae) in the eastern United States. Brimleyana 5:1-36. Repenning, C. A 1967. Subfamilies and genera ofthe Soricidae. U. S. Geol. Surv. Prof Pap. 565:1-74. . 1980. Faunal exchanges between Siberia and North America Canadian J. Anthropol. 1:3744. . 1987. Biochronology of the microtine rodents of the United States. Pp. 236-268 in M. O. Woodburne, ed. Cenozoic Mammals of North America, Geochronology and Biostratigraphy. Univ. California Press, Berkeley. , and F. Grady. 1988. The microtine rodents of the Cheetah Room Fauna, Hamilton Cave, West Virginia, and the spontaneous origin of Synaptomys. U. S. Geol. Surv. Bull. 1853:1-32. Robertson. J. S. 1976. Latest Pliocene mammals from Haile XVA Alachua County, Florida. Bull. Florida State Mul, Biol. Sci. 20(3):111-186. Savage, D. E. 1951. Late Cenozoic ve:tebrates ofthe San Francisco Bay region. Univ. California Publ., Bull. Dept Geol. Sci. 28:215-314. Sernken. H. A, Jr. 1966. Stratigraphy and paleontology ofthe McPherson Equus Beds (Sandahl Local Fauna), MePherson County. Kansas. Contrib. Mus. Paleon., Univ. Michigan 20(6):121-178. Shotwell. J. A 1970. Pliocene n,ammals of southeast Oregon and adjacent Idaho. Mul NaL Hist, Univ. Oregon. Bull. 17:1403. Simpson, 0. G. 1928. Pleisto©ene mammals from a cave in Citrus County, Florida. Amer. Mus. Nov. 328:1-16. Stephens. J. J. 1960. Stratigraphy and paleontology of a late Pleistocene basin. Harper County, Oklahoma. Geol. Soc. Amer. Bull. 71:1675-1702. Stirton, R. A 1965. Cranial morphology of Castoroides.· Pp 273-285 in Dr. D. N. Wadia Commernorative Volume. Mining Metallurgical Inst, India Taylor, A J. 1982. The mammatian fauna from the Mid-Irvinglonian Fyllan Cave local fauna Travis County, Texas. M. A Thesis, Univ. Texas, Austin. Van Valkenburgh, B., F. V. Grady, and B. KA 1990. The Plio-Pleistocene cheetah-like cat Miracinon,or inexpectatus ofNorth America. J. Val. Paleon. 10:434-454. Webb, S. D. 1974. Chronology of Florida Pleigtocene mammals. Pp. 5-31 in S. D. Webb, ed. Pleistocene Manunals of Horida. Univ. Presses Florida, Gainesville. MORGAN & WHITE: RObENTIA FROM LEISEY SHELL PIT 461 -, and K T. Wilkins, 1984. Historical biogeography of Florida Pleistocene mammals. Pp. 370-383 in H. H. Genoways and M. R. Dawson, eds. Contributions in Quaternary Vertebrate Paleontology: A volume in Memorial to John E. Guilday. Carnegie Mul Nat. Hist., Spec. Publ. 8. , G. S. Morgan. R. C. Hulbert Jr., D. S. Jooes, B. J. MacFadden, and P. A Mueller. 1989. Geochronology of a rich early Pleistooene vertebrate fauna Lcisey Shell Pit Tampa Bay. Florida. QuaL Res. 32:1-15. White, J. A. 1968. Anewporcupine from themiddle Pleistoceneofthe Anza-Bomgo Desert of California with notes on mastication in Coendou and Erethizon. Contrib. Sci. Los Angeles Co. Mus. Nat Hist 136:1-15. 1970. Late Cenozoic porcupines (Mammalia. Erethizontidae) ofNorth America. Amen Mus. Nov. 2421.1-15. 19918. North American Qorinae (Mammatia: Lagomorpha) from the late Miocene (Clarendonian) to latest Plioccne (Blancan). J. Vert Paleon. 11:6749. 1991b. A new Sylvilagus (Mammalia: Lagomorpha) from the Blancan (Phocene) and Irvingtonian (Pleistocene) of Florida. J. Veit Paleon. 11:243-246. Wilkins. K. T. 1984. Evolutionary trends in Florida Pleistocene pocket gophers (genus Geomys), with description of a new species. J. Vert Paleon. 3:166-181. 1985. Pocket gophers of the genus Thomomys (Rodentia: Geomyidae) from the Pleistocene of Florida. Proc. Biol. Soc. Washington 98:761-767. Winkler, A J., and F. V. Grady. 1990. The middle Pleistocene rodent Atopomys (Cricetidae: Arvicolinae) from the eastern and south-central United States. J. Vert Paleon.10:484-490. Woodburne, M. O. 1961. Upper Pliocene geology and vertebrate paleontology ofpart of the Meade Basin Kansas. Pap. Michigan Acad. Sci., Arts, Let, 1960 meeting, 46:61-101.