A New Species of Pocket Gopher (Genus Pappogeomys) From Jalisco, Mexico

Excerpt

J. R. Alcorn collected a number of pocket gophers of the genus Pappogeomys in the states of Jalisco, Nayarit, and Colima. The bulk of this material was obtained in 1949 and 1950. Full treatment of these interesting pocket gophers will be given by the author in a future publication.

Among the Pappogeomys collected by Alcorn were three specimens from the high Sierra del Tigre, an isolated range not previously sampled for pocket gophers. The Sierra del Tigre is situated in southern Jalisco and western Michoacán, and, like most of the mountainous terrain in this region of México, is volcanic in origin. To the south the Sierra del Tigre descends abruptly to lower elevations of the arid coastal plains, uninhabited by gophers of this genus. The small pocket gopher occurring in the Sierra del Tigre seems to be an undescribed species of the genus Pappogeomys which may be known as

Pappogeomys alcorni new species

Type.—Adult female, skull and skin; No. 39806, University of Kansas, Museum of Natural History; 4 mi. W Mazamitla, 6600 ft., Jalisco, México; October 18, 1950; obtained by J. R. Alcorn, original number 12835.

Distribution.—Known only from the Sierra del Tigre, and probably occurs only at higher elevations within the geographic limits of this isolated range of mountains.

Diagnosis.—Size medium for genus (see measurements); tail naked, short relative to length of head and body; hind foot short; hairs of upper parts and underparts Plumbeous basally and Orange-Cinnamon apically (capitalized color terms after Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912); large nasal patch Cinnamon-Buff in two specimens, but Pale Pinkish-Buff in holotype; white throat spot small and inconspicuous, throat mostly bright Cinnamon-Buff; auricular patch pure Plumbeous, hairs lacking cinnamon-colored tips; tarsi with Cinnamon-Buff hairs; dentition as in P. bulleri except that enamel plate of posterior wall of M1 reduced to a vestige present only on inner fourth, outer three-fourths of posterior wall of M1 without trace of enamel; zygomata slender, bowed outward; jugal long, widely separating maxillary and squamosal arms of zygoma; skull deep (measured from a point on the frontal to a point on the palate directly below and between the maxillary teeth); rostrum narrow and short; nasals broadly truncate posteriorly, and not decurved anteriorly; narrow across mastoid processes of squamosals; anterior palatine foramina small and rounded in outline, not slitlike.

Comparisons.—Compared with Pappogeomys bulleri, the only other named species of the genus, P. alcorni differs, as follows: Nasal patch cinnamon or buffy instead of white; enamel plate of posterior wall of M1 reduced to inner fourth rather than developed completely across posterior wall of tooth; nasals broadly truncate posteriorly instead of narrow and emarginate; anterior palatine foramina short and round instead of long and slitlike.

Measurements.—The type and an adult female topotype (in parentheses) measure, as follows: Total length, 210 (210); length of tail, 61 (63); length of hind foot, 29 (28); condylobasal length, 38.0 (36.9); basilar length, 32.8 (31.9); breadth across zygomata, 24.2 (24.8); palato-frontal depth, 15.0 (14.8); palatal length, 24.7 (24.1); length of nasals, 12.7 (12.8); breadth of braincase, 18.1 (17.5); breadth across mastoid processes of squamosals, 21.5 (21.4); breadth of rostrum, 8.4 (8.1); length of rostrum, 16.9 (16.3); alveolar length of maxillary tooth-row, 9.3 (8.8); breadth across angular processes of rami, 26.1 (26.2)....