Two New Moles (Genus Scalopus) from Mexico and Texas

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Two New Moles (Genus Scalopus)
from Mexico and Texas


BY

ROLLIN H. BAKER


University of Kansas Publications
Museum of Natural History

Volume 5, No. 2, pp. 17-24
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. 2, pp. 17-24
February 28, 1951

UNIVERSITY OF KANSAS
Lawrence, Kansas


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


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Two New Moles (Genus Scalopus)
from Mexico and Texas

BY

ROLLIN H. BAKER


In the spring of 1950, a field party from the University of Kansas
Museum of Natural History including J. R. Alcorn, W. J. Schaldach, Jr.,
George Newton, and the author collected mammals in the Mexican state of
Coahuila. A few days were spent in the Sierra del Carmen. One morning
when examining sets for pocket gophers in these mountains, Alcorn found
a mole caught in one of the traps. Subsequent examination discloses
that this specimen belongs to a heretofore unknown species which may be
named and described as follows:


=Scalopus montanus= new species

     _Type._--Male, adult, skin and skull plus body skeleton; no.
     35668, Univ. Kansas Mus. Nat. Hist.; Club Sierra del Carmen,
     2 mi. N and 6 mi. W Piedra Blanca, Coahuila, Mexico; 7 April
     1950; obtained by J. R. Alcorn, original no. 11093.

     _Range._--Known only from the type locality; probably found
     in other localities in the Sierra del Carmen of northern
     Coahuila, Mexico.

     _Diagnosis._--Size medium and slender for the genus (see
     measurements); tail medium in length, sparsely covered with
     whitish hairs; claws of forefeet slender; upper parts near
     (h) Buffy Brown (capitalized color terms after Ridgway,
     Color Standards and Color Nomenclature, Washington, D. C.,
     1912), with slight rufous wash on top of head; underparts
     resemble upper parts but slightly paler with longitudinal
     band of near (14) Sudan Brown extending from chin
     posteriorly to and around base of tail, less intense on
     breast; skull small, arched, and relatively slender
     especially across mastoidal region; posterior part of
     cranium depressed; foramen magnum low when viewed from rear;
     external pterygoid region not greatly expanded; teeth small,
     especially upper third molar.

     _Comparison._--From _Scalopus aquaticus_, of which ten
     subspecies have been seen including those of significant
     geographic position, _S. montanus_ differs in: Skull
     slenderer, less angular and relatively narrower across
     mastoidal region; cranium arched with hind part flattened;
     external pterygoid region less expanded; teeth relatively
     small, especially last upper molar. From _S. inflatus_,
     known to me from Jackson's description (N. Amer. Fauna,
     38:53-54, pls. 2, 3, September 30, 1915), _S. montanus_
     differs in: Skull less angular and slenderer, prelachrymal
     region not inflated; zygomata slenderer.

_Remarks._--_S. montanus_ is known from a single specimen, which
represents the second known occurrence of the genus _Scalopus_ in
Mexico. The other occurrence is that of _S. inflatus_ in the state of
Tamaulipas. _S. montanus_ is geographically isolated in mountainous
country from other species of _Scalopus_. Ten of the recognized
subspecies of _S. aquaticus_ were available for examination and
descriptions of others were studied. It was found that the number and
magnitude of the differences separating any one of these subspecies
from an adjoining one was less than those separating _S. montanus_ from
_S. a. texanus_ and _S. a. intermedius_, which are, geographically,
closest to _S. montanus_. _S. montanus_ seems not to be closely related
to _S. inflatus_ of Tamaulipas. _S. montanus_ is given specific rank
because of the great degree of difference between it and its nearest
relatives, and because of its geographically isolated position.

The specimen of _S. montanus_ was taken in a tunnel found by digging
away a mound thought to be that of the pocket gopher, _Thomomys
sturgisi_. A trap set in one direction in the tunnel caught the mole; a
trap set in the other direction in the tunnel was later covered with
soil, evidently by a gopher. After the capture a thorough inspection of
the area revealed no "raised" tunnels, typical of _Scalopus_. A series
of _Thomomys_ was taken in this area in sets placed in tunnels found
under similar mounds. This locality was near the headquarters of the
Club Sierra del Carmen in a parklike stand of oak timber in a cañon, at
an elevation of 4950 ft. as recorded by our altimeter. The plant
association was judged to be characteristic of the Upper Sonoran
Life-zone, not far below the beginning of the Transition Life-zone. The
area was heavily grazed by goats, hogs and horses and had little grass
or other ground cover under the trees. The soil in this cañon was not
deep and consisted of a rocky, marly mixture, pale red in color,
evidently produced by weathering of the reddish volcanic rocks
bordering the cañon.

The Sierra del Carmen is a high, igneous range, surrounded for the most
part by Lower Sonoran plains and desert. Zoologically, these mountains
are poorly known. Few collectors have been in the area; most of these
have been afforded accommodations through the Club Sierra del Carmen
(Carmen Mountain Hunting Club), the members of which have been
especially interested in assisting naturalists. Several kinds of
mammals are known only from this "biological island" including the
pocket gopher mentioned above and the shrew, _Sorex milleri_. The
finding of a mole in the higher elevations of this range suggests that
moles may occur in other mountainous areas of Mexico.

Assistance with field work is acknowledged from the Kansas University
Endowment Association.

     _Measurements._--The adult, male holotype measures as
     follows: Total length, 150; tail vertebrae, 27; hind foot,
     20; greatest length (of skull), 32.2; palatilar length,
     13.8; mastoidal breadth, 16.2; interorbital breadth, 7.0;
     maxillary tooth-row, 11.3; greatest depth of skull including
     auditory bullae, 9.4; weight, 38.6 grams.

     _Specimen examined._--One, from the type locality.

In studying _Scalopus aquaticus texanus_, I noted that Allen (Bull.
Amer. Mus. Nat. Hist., 3:221, April 29, 1891) based the original
description on a single, unsexed specimen taken in Presidio County,
Texas, by Wm. Lloyd in September, 1887. Later, Allen wrote (Bull. Amer.
Mus. Nat. Hist., 5:200, August 18, 1893) that a series of moles from
Rockport, Aransas County, Texas, agreed essentially with the type. True
(Proc. U. S. Nat. Mus., 19:22, December 21, 1896) believed that the
type was actually from Aransas County rather than Presidio County. This
belief was shared by later workers. In checking the literature, I find
that the collector of the type, Wm. Lloyd, who was obtaining specimens
for George B. Sennett at the time, took other mammals in September as
well as in October of 1887 in Presidio County (see Allen, Bull. Amer.
Mus. Nat. Hist., 3:221, 223, 224, April 29, 1891) and birds there in
June of 1887 (see Sennett, Auk, 5:43, January, 1888). I can find no
evidence that Lloyd collected in or near Aransas County in 1887 and see
no reason for doubting that the locality, Presidio County, as written
on the original label of the type of _S. a. texanus_ is correct. Mr. M.
J. Carroll of the Texas State Historical Association advises me that in
1887, Presidio County was reduced to its present size by the creation
of Brewster and Jeff Davis counties. Lloyd might have taken the mole in
any one of these three Trans-Pecos counties. Even so, these counties
are widely separated geographically from the range of other moles
designated as _S. a. texanus_ (see Davis, Amer. Midl. Nat., 27:386,
March, 1942). The taking of _S. montanus_ in the Sierra del Carmen
immediately south of Trans-Pecos Texas leads me to think that Lloyd's
mole might have been taken in a mountainous region within one of the
three counties mentioned above. A description of _Scalopus aquaticus
texanus_ Allen follows:


=Scalopus aquaticus texanus= Allen

         _Scalops argentatus texanus_ Allen, Bull. Amer. Mus.
         Nat. Hist., 3:221, April 29, 1891.

     _Type._--Sex unknown, adult, skin no. 3488, skull no. 2740,
     Amer. Mus. Nat. Hist.; Presidio County, Texas; September,
     1887, obtained by Wm. Lloyd.

     _Range._--Limits of range in Trans-Pecos Texas unknown.

     _Diagnosis._--Size small; rostrum heavy and broad; lower
     jaws heavy; palatine space wide with upper tooth-rows arched
     laterally; teeth large, especially fourth premolar and
     molars.

     _Comparison._--From adults of comparable age from Rockport,
     Aransas County, Texas, _S. a. texanus_ differs in: Rostrum
     broader and heavier; lower jaws heavier; palatine space
     wider, with upper tooth-rows more arched laterally;
     individual teeth in both jaws larger, especially fourth
     premolar and molars. From _S. a. intermedius_, which is
     geographically nearest to the northeast (adult specimens
     from Meade, Clark and Barber counties, Kansas, and Dewey
     County, Oklahoma), _S. a. texanus_ differs in: Size smaller;
     rostrum less massive and shorter; tooth-row shorter.

_Remarks._--The type has been previously examined by True (_op.
cit._:44). The skin is faded and of little taxonomic worth. The
anterior part of the skull is present along with both upper tooth-rows
and most of the lower jaws. The teeth are well worn, indicative of old
adulthood. In size, _S. a. texanus_ appears closest to moles from
southern Texas (Rockport) which previously were assigned to the
subspecies _Scalopus aquaticus texanus_. The tooth-rows are of the same
length, but the individual teeth of _S. a. texanus_ are significantly
larger.

The moles in southern Texas previously ascribed to _Scalopus aquaticus
texanus_ seem to be without a name and may be known as follows:


=Scalopus aquaticus alleni= new subspecies

         _Scalops texanus_, Allen, Bull. Amer. Mus. Nat. Hist.,
         5:200, August 18, 1893.

         _Scalops aquaticus texanus_ True, Proc. U. S. Nat. Mus.,
         19:21, December 21, 1896.

         _Scalopus aquaticus texanus_ Jackson, N. Amer. Fauna,
         38:50, September 30, 1915; Miller, U. S. Nat. Mus.,
         Bull. 128:15, April 29, 1924; Davis, Amer. Midl. Nat.,
         27:386, March, 1942.

     _Type._--Male, adult, skin no. 7189, skull no. 5788, Amer.
     Mus. Nat. Hist.; Rockport, Aransas County, Texas; 29 January
     1893; obtained by H. P. Attwater.

     _Range._--Southern Texas, north to Bexar County and east to
     Refugio County (see Davis, _loc. cit._).

     _Diagnosis._--Size small; according to Davis (_loc. cit._),
     "... length of hind foot seldom more than 19 mm.; total
     length seldom more than 140 mm. Skull small and flat, seldom
     exceeding 33 mm. in occipitonasal length and seldom
     equalling 10 mm. in depth; maxillary breadth usually less
     than 10 mm.; alveolar length of maxillary tooth row seldom
     more than 10.5 mm."

     _Comparison._--From _S. a. cryptus_, geographically adjacent
     to the east, _S. a. alleni_ differs in: Size smaller; color
     paler; skull smaller and flatter. From _S. a. intermedius_,
     geographically adjacent to the north, _S. a. alleni_ differs
     in: Size smaller; skull smaller and flatter with shorter
     tooth-row (see Davis, _op cit._:384, 385). For comparison
     with _S. a. texanus_, see account of that subspecies.

_Remarks._--This mole is named in honor of Dr. J. A. Allen in
recognition for his work on Texas mammals. Grateful acknowledgment is
made to those in charge of the collection of Recent mammals in the
American Museum of Natural History for permitting me to examine the
moles from Aransas County and the type specimen of _Scalops argentatus
texanus_ Allen.

_Transmitted January 15, 1951._


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