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                 A New Pocket Gopher (Genus Thomomys)
                      From Wyoming and Colorado

                                  BY

                           E. RAYMOND HALL


                  University of Kansas Publications
                      Museum of Natural History

                    Volume 5, No. 13, pp. 219-222
                          December 15, 1951


                         University of Kansas
                               LAWRENCE
                                 1951




     UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

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

                    Volume 5, No. 13, pp. 219-222
                          December 15, 1951

                         UNIVERSITY OF KANSAS
                           Lawrence, Kansas


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

                               24-1359




                 A New Pocket Gopher (Genus Thomomys)
                      from Wyoming and Colorado

                                  By
                           E. RAYMOND HALL


Among small mammals accumulated, from Wyoming, in the Museum of Natural
History of the University of Kansas, specimens of the wide-spread
species _Thomomys talpoides_ are abundantly represented. Subspecific
names are available for most of these, but specimens from the Sierra
Madre Mountain Range of Wyoming and Colorado prove upon comparison to
pertain to an heretofore unnamed subspecies which may be described and
named as follows:


             #Thomomys talpoides meritus# new subspecies

    _Type._--Male, adult, skull and skin, no. 25628 Mus. Nat. Hist.
    Univ. Kansas; from 8 mi. N and 19-1/2 mi. E Savery, 8800 ft.,
    Carbon County, Wyoming; obtained on July 19, 1948, by George M.
    Newton; original no. 4.

    _Range._--Sierra Madre Mountain Range of southern Wyoming and
    northern Colorado.

    _Diagnosis._--Size small (see measurements); color dark,
    upperparts in worn pelage of July darker than (near, _n_) Raw
    Umber (capitalized terms are of Ridgway, Color Standards and
    Color Nomenclature, Washington, D. C., 1912) and in fresh pelage
    of August between (near, 16') Prout's Brown and Mummy Brown;
    skull small; relative to basilar length, skull narrow across
    rostrum, zygomata and mastoids; nasals short and posteriorly
    truncate; premaxillae extending behind nasals; temporal lines
    faint and divergent posteriorly.

    _Comparisons._--From _Thomomys talpoides rostralis_ (North
    Platte River Valley, SW of Saratoga, Wyoming), the subspecies to
    the east and south, _T. t. meritus_ differs in: Lesser size,
    darker color, smaller and slenderer skull. The slenderness is
    especially noticeable in the breadth across the zygomata,
    mastoids, and rostrum. From _Thomomys talpoides clusius_
    (topotypes), the subspecies to the north and west, _T. t.
    meritus_ differs in: Color much darker; rostrum longer; skull
    narrower across mastoids and zygomata; tympanic, and also
    mastoid, bullae smaller. Resemblance to _T. t. clusius_ is shown
    in the narrowness of the skull interorbitally and in the
    shortness of the tooth-row.

_Remarks._--The specimens of _Thomomys_ from Wyoming on which the name
_T. t. meritus_ is based were obtained by Mr. E. Lendell Cockrum and his
associates with the thought that intergradation might be shown between
_T. t. rostralis_ to the east and _T. t. clusius_ to the west. The
animals showed instead, that there was a subspecies differing from
each of the two mentioned subspecies in small size, dark color and
slenderness of skull. Acknowledgment of assistance with field work is
made to the Kansas University Endowment Association.

    _Measurements._--Average and extreme measurements of seven adult
    males and five adult females, from the type locality, are as
    follows: Total length, [Male] 204 (193-226), [Female] 207
    (193-210); length of tail, 56 (46-68), 56 (50-63); length
    of hind foot, 27.6 (26-30), 27.4 (27-28); basilar length,
    30.7 (29.0-33.0), 30.1 (29.5-30.7); zygomatic breadth, 20.4
    (18.9-21.6), 19.5 (18.8-20.0); least interorbital breadth, 6.2
    (5.8-6.6), 6.1 (5.9-6.3); mastoidal breadth, 17.9 (16.9-18.5),
    17.2 (16.7-17.6); length of nasals, 13.7 (12.4-14.7), 13.2
    (12.8-13.9); breadth of rostrum, 7.0 (6.5-7.5), 6.9 (6.7-7.3);
    length of rostrum, 16.3 (15.3-17.5), 15.8 (15.3-16.1); alveolar
    length of maxillary tooth-row, 7.1 (6.9-7.3), 7.1 (6.8-7.5).

    _Specimens examined._--Total number 26 and unless otherwise
    indicated in the Museum of Natural History of the University of
    Kansas.

    #Wyoming.#--_Carbon County_: Savery (8 mi. N and 19-1/2 mi. E,
    8800 ft., 12; 7 mi. N and 17 mi. E, 8300 ft., 1; 6 mi. N and
    12-1/2 mi. E, 8400 ft., 1; 6 mi. N and 13-1/2 mi. E, 8400 ft.,
    2; 6 mi. N and 14-1/2 mi. E, 8350 ft., 1; 5 mi. N and 3 mi. E,
    6800 ft., 1; 4 mi. N and 8 mi. E, 7800 ft., 7300 ft., 3; 4 mi. N
    and 10 mi. E, 7800 ft., 3) 24.

    #Colorado#--_Routt Co._ ?: Elkhead Mts., 20 mi. SE Slater, 2 (U.
    S. B. S.).


_Museum of Natural History, University of Kansas, Lawrence. Transmitted
October 20, 1951._


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