




Transcriber's Note.

The layout of the column headings in the table at the end of this text
has been changed for ease of reading. Otherwise the text remains
unchanged.






          Two New Pocket Gophers from Wyoming
                    and Colorado

                         BY

         E. RAYMOND HALL and H. GORDON MONTAGUE





           University of Kansas Publications

              Museum of Natural History

             Volume 5, No. 3, pp. 25-32

                 February 28, 1951




               University of Kansas

                     LAWRENCE

                       1951





 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

    Editors: E. Raymond Hall, Chairman, Edward H. Taylor,
            A. Byron Leonard, Robert W. Wilson

                Volume 5, No. 3, pp. 25-32

                   February 28, 1951




                  UNIVERSITY OF KANSAS

                    Lawrence, Kansas




                      PRINTED BY
            FERD VOILAND, JR., STATE PRINTER
                    TOPEKA, KANSAS
                        1951


                       23-6627





      Two New Pocket Gophers from Wyoming and Colorado

                         BY

         E. RAYMOND HALL AND H. GORDON MONTAGUE


In the academic year of 1947-48 Montague studied the geographic
variation in _Thomomys talpoides_ of Wyoming. His study was based upon
materials then in the University of Kansas Museum of Natural History.
Publication of the results was purposely delayed until previously
reported specimens from certain adjacent areas, especially in Colorado,
could be examined. In the autumn of 1950 one of us, Hall, was able to
examine the specimens from Colorado; also, the specimens from Wyoming
accumulated in the past two seasons of field work in Wyoming were
examined by Hall. A result of these studies is the recognition of two
heretofore unnamed subspecies of the northern pocket gopher in
southeastern Wyoming.

Grateful acknowledgment is made of the opportunity to study the
Coloradon specimens in the Biological Surveys Collection of the United
States National Museum, and of the financial assistance from the Kansas
University Endowment Association which permitted the field work in
Wyoming.

Descriptions and names for the two new subspecies are given below:


=Thomomys talpoides rostralis= new subspecies

_Type._--Female, adult, skull and skin, no. 17096 Mus. Nat. Hist., Univ.
Kansas; from 1 mi. E Laramie, 7164 ft., Albany County, Wyoming; obtained
on July 16, 1945, by C. Howard Westman; original no. 320.

_Range._--Southern Wyoming and south in the mountains of Colorado to the
Arkansas River but not including the Colorado River drainage except in
Grand County and part of Routt County.

_Diagnosis._--Size medium (see measurements); upper parts ranging from
between Cinnamon-Rufous and Hazel (capitalized terms are of Ridgway,
Color Standards and Color Nomenclature, Washington, D. C., 1912) in the
eastern part of the range to between Argus Brown and Brussels Brown in
the western part of the range; sides Cinnamon-Rufous; throat whitish;
remainder of under-parts whitish, in many specimens tipped with
Ochraceous-Buff; feet and tail whitish; rostrum long; nasals ordinarily
truncate posteriorly; temporal ridges nearly parallel; interpterygoid
space broadly V-shaped.

_Comparisons._--From _Thomomys talpoides clusius_ (topotypes), _T. t.
rostralis_ differs in: Body longer; color more reddish (lighter with
less brownish and more ochraceous); rostrum both longer and broader,
actually and also in relation to length of the skull; skull broader
interorbitally; upper molariform tooth-row longer; tympanic bullae less
inflated. For comparison with _T. t. attenuatus_ to the east, see the
account of that subspecies.

From _Thomomys talpoides macrotis_ (topotypes) to the southeast, _T. t.
rostralis_ differs in: Body shorter; upper parts slightly more
ochraceous and less grayish; skull averaging smaller in all measurements
except that interorbital region is broader and rostrum and upper
molariform tooth-row are longer; nasals truncate versus emarginate, and
consistently shorter; basilar length consistently less in specimens of
equal age; mastoidal breadth less in 16 of 17 specimens of _rostralis_;
temporal ridges parallel instead of divergent posteriorly; exposed parts
of upper incisors shorter; tympanic bullae more angular
antero-laterally.

From _Thomomys talpoides fossor_ (specimens from Rico, Silverton, Hermit
and Pagosa Springs, all in Colorado), the subspecies to the southward,
_T. t. rostralis_ differs in: Longer body; lighter color of upper parts;
nasals truncate rather than rounded posteriorly; temporal ridges more
nearly parallel (less divergent posteriorly); rostrum longer (averaging
longer and broader); skull wider across zygomatic arches in 11 of 12
specimens of _rostralis._

_Remarks._--Geographic variation is evident in the material examined. In
the initial study, one of us, Montague, separated the material from the
Medicine Bow Range in Wyoming as a subspecies different from that at
Laramie and the adjoining mountains to the eastward because of the
darker color of the western animals and the smaller size of males.
Acquisition of more material from still farther west (Sierra Madre) in
Wyoming and the examination of material in the United States Biological
Surveys Collection from Colorado discloses that there is a cline of
increasing intensity of color from the geographic range of _T. t.
cheyennensis_ at Pine Bluffs, Wyoming, westward to the eastern side of
the Sierra Madre at a locality three miles east and five miles north of
Savery, Wyoming. A further deterrent to setting apart the animals of the
Medicine Bow Mountains as a separate subspecies is the large size of
males from the North Platte River Valley southeast of Saratoga. The
males from the valley of the North Platte are intermediate in size
between those from the Medicine Bow Mountains and those from the Laramie
River Valley. Females from the same places are available in longer
series and show less variation. If there is a difference in size in the
females, those from the mountains are larger than those from lower
elevations on either side.

The examination that one of us, Hall, has made of the related materials
from Colorado reveals, as we supposed would be the case, that a large
area formerly assigned to the geographic range of _Thomomys talpoides
fossor_ is to be assigned to the geographic range of the newly named
_Thomomys talpoides rostralis._ It should be added that, at this
writing, the lack of ideally complete material from southwestern
Colorado leaves some doubt as to the range of variation properly to be
included within the geographic range of _T. t. fossor._ Consequently,
study of a larger number of specimens from more localities in Colorado
may show that the boundary between the geographic ranges of _T. t.
fossor_ and _T. t. rostralis_ should be shifted from where we have
tentatively placed it.

_Specimens examined._--Total number, 168. Unless otherwise indicated,
those from Colorado are in the United States National Museum, Biological
Surveys Collection, and those from Wyoming are in the Museum of Natural
History of the University of Kansas.

=Colorado.= _Routt Co._: Hahns Peak, 2; Hayden, 1. _Jackson Co._ Pearle,
North Park, 9000 ft., 2; Canadian Creek, North Park, 6; 5 mi. E Canadian
Creek, 1; Rabbit Ear Mts., Arapaho Pass, 5. _Larimer Co._: Elkhorn, 7000
ft., 1; Estes Park, 7. _Grand Co._: Coulter, 4. _Boulder Co._: Longs
Peak, 3; Gold Hill (the skin only; skull does not belong), 1; 3 mi. S
Ward, 9000 ft., 10 (K. U.); 5 mi. W Boulder, 7. _Gilpin Co._: Blackhawk
(U. S. N. M.), 2. _Jefferson Co._: Golden, 1; Golden foothills, 7300
ft., 1. _Park Co._: Como, South Park, 9800 ft., 1. _El Paso Co._:
Cascade, 1 (too young for certain sub-specific identification).

=Wyoming.= _Carbon County_: 13 mi. E and 6 mi. S Saratoga, 8500 ft., 1;
14 mi. E and 6 mi. S Saratoga, 8800 ft., 1; 7 mi. S and 11 mi. E
Saratoga, 5; 8 mi. S and 6 mi. E Saratoga, 10; 10 mi. N and 14 mi. E
Encampment, 8000 ft., 2; 10 mi. N and 16 mi. E Encampment, 8000 ft., 1;
8 mi. N and 16 mi. E Encampment, 8400 ft., 10. _Albany Co._: 2-1/4 mi.
ESE Browns Peak, 10300 ft., 7; 3 mi. ESE Browns Peak 10000 ft., 5; 2 mi.
S Browns Peak, 10600 ft., 7; 3 mi. S Browns Peak, 1; 2 mi. E and 1/2 mi.
S Medicine Bow Peak, 10800 ft., 2; 5 mi. N Laramie, 7200 ft., 1; 1 mi. E
Laramie, 7164 ft., 18; Laramie Mts., 10 mi. E Laramie (8500 ft., 2; 9000
ft., 1), 3 (U. S. B. S.); 5-1/2 mi. ESE Laramie, 8500 ft., 4; 8 mi. E
and 4 mi. S Laramie, 8600 ft., 5; 8 mi. E and 6 mi. S Laramie, 8500 ft.,
1; 15 mi. SE Laramie, Pole Mtn., 8200 ft., 3 (U. S. B. S.); 1 mi. SSE
Pole Mtn., (8250 ft., 4; 8350 ft., 6), 10; 1 mi. S Pole Mtn., 8350 ft.,
2; 2 mi. SW Pole Mtn., 8300 ft., 6; 2-1/2 mi. S Pole Mtn., 8340 ft., 1;
3 mi. S Pole Mtn., 1; Woods P. O., 2 (U. S. N. M.); Fort Russell, 1 (U.
S. N. M.); Sherman, 2 (U. S. N. M.).

_Additional records._--Bailey (N. Amer. Fauna, 39:101, 112, November 15,
1915) has recorded the following specimens, which on geographic grounds,
would presumably be referable to _Thomomys talpoides rostralis._
COLORADO: Estes Park (referred by Bailey, p. 101, to _T. t. clusius_),
1; Colorado City, 1; Colorado Springs, 2-1/2 mi. N, 6000 ft., 1;
Colorado Springs, east of Palmer Park, 1; Montgomery, 3; Nederland, 4;
Teller County Divide, 1. These specimens have not been examined by us.


=Thomomys talpoides attenuatus= new subspecies

_Type._--Male, adult, skull and skin, no. 15095 Mus. Nat. Hist., Univ.
Kansas; from 3-1/2 mi. W Horse Creek Post Office, 7000 ft., Laramie
County, Wyoming; obtained on July 16, 1945, by Henry W. Setzer; original
no. 629.

_Range._--Southeastern Wyoming from Niobrara County south into Weld
County, Colorado.

_Diagnosis._--Size small; color pale (whitish); skull smooth and,
relative to its length, slender; rostrum relatively long; nasals
truncate posteriorly; middle parts of zygomatic arches straight;
temporal ridges low and more widely separated in middle extent than at
anterior or posterior ends; tympanic bullae rounded and moderately
inflated; interpterygoid space V-shaped.

_Comparisons._--From _Thomomys talpoides bullatus_ (topotypes) to the
northward, _T. t. attenuatus_ differs in smaller size, lighter (less
brownish, more whitish) color, smaller and slenderer skull. In detail,
some cranial features diagnostic of _attenuatus,_ when compared with
_bullatus,_ are: Anterolateral angle of zygoma less nearly a right
angle; temporal ridges bowed outward at middle, instead of straight, and
farther apart posteriorly than anteriorly instead of nearly parallel;
sides of basioccipital nearly straight instead of concave.

From _Thomomys talpoides cheyennensis_ (holotype and Wyoming specimens
from: Pine Bluff; 1 mi. W Pine Bluffs, 5000 ft.; 12 mi. N and 1/2 mi. W
Pine Bluffs) to the eastward, _T. t. attenuatus_ differs in smaller size
throughout and more slender skull. The two subspecies are
indistinguishable in color.

From _Thomomys talpoides macrotis_ (topotypes) to the southward, _T. t.
attenuatus_ differs in smaller size, slightly lighter (less brownish and
more whitish) color, smaller and slenderer skull.

From _Thomomys talpoides rostralis_ (specimens from the type locality)
to the westward, _T. t. attenuatus_ differs in smaller size; lighter
(grayer, less brownish) color, smaller and less angular skull.

From _Thomomys talpoides clusius_ (topotypes) to the northwestward, _T.
t. attenuatus_ differs in shorter body, slightly grayer color, less
width across mastoid region of skull, smaller tympanic bullae, and more
obtuse anterolateral angle on zygoma.

_Remarks._--This subspecies is of smaller size than any of the
geographically adjoining subspecies. Intergradation with _T. t.
cheyennensis_ is shown by specimens from two miles south and nine and
one-half miles east of Cheyenne, Wyoming. Intergradation with _T. t.
bullatus_ or _T. t. clusius_ or both is suggested by the larger size of
the specimen from five miles southwest of Wheatland, Wyoming. Although
large, this skull has the slender proportions of _attenuatus_ to which
the specimen is tentatively referred. Although the specimens from Avalo,
Colorado, are typical _attenuatus,_ the specimen from Pawnee Buttes,
Colorado, is somewhat larger than typical _attenuatus_ and suggests
intergradation with the subspecies to the southward, for example, at
Flagler, Colorado.

_Specimens examined._--Total number, 44, and unless otherwise indicated
in the Museum of Natural History of the University of Kansas.

=Wyoming.= _Niobrara County_: 10 mi. N Hatcreek Post Office, 5300 ft.,
1. _Platte Co._: 5 mi. SW Wheatland, 1 (U. S. B. S.). _Goshen Co._:
Little Bear Creek, 20 mi. SE Chugwater, 1 (U. S. B. S.). _Laramie Co._:
5 mi. W and 1 mi. N Horse Creek P. O., 7200 ft., 1; 3-1/2 mi. W Horse
Creek P. O., 7000 ft., 6; 2-1/5 mi. W Horse Creek P. O., 6600 ft., 1; 2
mi. W Horse Creek P. O., 6600 ft., 2; Horse Creek 6500 ft., 1; 3 mi. E
Horse Creek P. O., 6400 ft., 5; 6 mi. W Islay, 2 (U. S. B. S.); 2 mi. S
and 1/2 mi. E Pine Bluffs, 5200 ft., 1; 7 mi. W

Cheyenne, 6500 ft., 1; Cheyenne, 7 (U. S. N. M.); 1 mi. S and 4-1/2 mi.
E Cheyenne, 5200 ft., 1; 2 mi. S and 9-1/2 mi. E Cheyenne, 5200 ft., 3;
Arcola, 5200 ft., 4.

=Colorado.= _Weld Co._: Pawnee Buttes, 5300 ft., 1 (U. S. B. S.). _Logan
Co._: Chimney Canyon, 10 mi. NE Avalo, 5100 ft., 5 (U. S. B. S.).

_Museum of Natural History, University of Kansas, Lawrence. Transmitted
January 15, 1951._




TABLE 1. MEASUREMENTS, IN MILLIMETERS, OF TWO SUBSPECIES OF THOMOMYS
TALPOIDES.
______________________________________________________________________

  Column A  Catalogue number or number of averaged individuals
  Column B  Sex
  Column C  Total length
  Column D  Length of tail
  Column E  Basilar length
  Column F  Length of hind foot
  Column G  Zygomatic breadth
  Column H  Least interorbital constriction
  Column I  Mastoidal breadth
  Column J Length of nasals
  Column K Breadth of rostrum
  Column L Length of rostrum
  Column M Alveolar length if maxilliary tooth-row


   A    |  B   | C | D | E  | F  | G  | H  | I  | J  | K  | L  |  M

                    _T. t. rostralis,_ from type locality

 17092  |Male  |220|56 |28  |33.2|23.7|6.4 |19.5|15.5|8.1 |17.5| 8.2
 17095  |Male  |228|68 |30  |33.3|  - |6.5 |18.8|15.0|7.4 |17.3| 7.3
 17091  |Male  |212|56 |27  |33.0|22.8|6.5 |18.7|14.2|8.5 |16.2| 7.6
 Average|Male  |220|60 |28.3|33.2|23.2|6.5 |19.0|14.9|8.0 |17.0| 7.7
 9 av.  |Female|214|56 |27.1|31.6|22.4|6.5 |18.5|14.4|7.8 |16.8| 7.9
 min.   |Female|198|45 |25  |30.0|20.7|6.2 |17.7|13.2|7.4 |15.4| 7.1
 max.   |Female|230|72 |28.5|33.5|23.3|7.0 |19.8|14.9|8.1 |17.7| 8.4

                    _T. t. attenuatus,_ from type locality

 15095  |Male  |202|61 |26  |30.1|21.2|6.6 |18.2|13.6|7.3 |16.0| 7.0
 15094  |Male  |189|56 |24  |29.7|20.1|5.7 |17.2|12.4|7.2 |14.8| 6.9

                  from 2-1/2 mi. W Horse Creek P. O., 6600 ft.

 15100  |Male  |196|58 |27  |30.2|21.7|6.1 |18.4|14.5|7.5 |16.3| 7.0
 3 av.  |Male  |196|58 |25.7|30.0|21.0|6.1 |17.9|13.5|7.3 |15.7| 7.0

                           from type locality

 15096  |Female|203|59 |26  |30.0|  - |6.1 |18.0|14.1|7.3 |16.3| 6.8
 15098  |Female|192|69 |26  |28.8|19.8|5.5 |17.2|12.0|6.7 |14.7| 7.3

                          Horse Creek, 6500 ft.

 15103  |Female|181|58 |25  |29.6|19.5|5.9 |16.3|13.0|6.9 |15.2| 7.0

                   3 mi. E Horse Creek P. O., 6400 ft.

 15107  |Female|190|54 |27  |30.5|20.5|6.0 |17.9|13.5|7.3 |16.4| 6.8
 15106  |Female|192|55 |26  |30.8|21.5|6.5 |18.2|12.7|7.6 |15.5| 7.0
 5 av.  |Female|192|59 |26  |29.9|20.3|6.0 |17.5|13.1|7.2 |15.6| 7.0






