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Ammospermophilus interpres

1990; Oxford University Press; Linguagem: Inglês

10.1093/mspecies/365.1

1545-1410

Troy L. Best, Cynthia L. Lewis, Katharine Caesar, Amy S. Titus,

Parasitic Diseases Research and Treatment

The genus Ammospermophilus contains five species; A. harrisii, A. insularis, A. interpres, A. leucurus, and A. nelsoni.A key to the species is presented in Best et al. (1990).A. interp res is monotypic (Hall, 198 1).The dental formula is i Ill , c 0 /0, P 21 1, m 3/3, total 22 (Ingles, 1965).There is a tren d toward increased size in north ern individuals (Hafner, 1981).Average and range of measur ements (in mm) of eight males and two females from El Paso, Texas, are: total length, 226 (220-235); length of tail vert ebrae , 74 .2(68-84); length of hind foot, 37 .8(36-40 ); and length of ear (dry), 9.8 (8 -11).Cranial measurements (in mm) of eight males and six females from EI Paso are: greatest length , 39.3 (37.7-40.5);palatilar length, zygomatic breadth,cranial breadth ,interorbital breadth ,postorbital constriction,14153); length of nasals, 12 .6(1l .8-13 .8);and length of maxillary toothrow, 6.6 (6.4 -6.9; Howell, 19 38) .Additional measurements (in mm) of four adult females from near Boquillas, Coahuila, are : length of ear , 14 (14 -1 5); condylobasal length , 39. 5 (38 .4-40.1); and basilar length , 31.9 (30 .8-32 .8;Baker , 1956).Measurements (in mm) of two adult females from Guadalupe Mountains National Park include mastoid breadth, 20 .7 , 19.6 (Genoways et al., 1979).Average and extreme weights of four adult, nonpr egnant females from near Boquillas, Coahuila, were 1l0.2 g (98 .7 -121.9;Baker , 1956) .DISTRIBUTION.The Texas antelope squirrel occupies the high intermontane Chihuahu an Plate au from Jaral, Coahuila, near Cinco de Mayo, Zacatecas, and Ciudad Lerdo, Durango, north ern through western Texas into central New Mexico (Fig. 3;Baker et al., 1980;Hafner, 1984).The species is restricted to rocky associations on and around the low-desert mountain range s (Hafner , 1981).Stones, boulders, and rocks are essential environmental featur es for A. int erpres (Schmidly, 1977 b). it occur s at 1,800 m in the Chisos Mountains, Texas (Judd , 1967), and it is widely distributed from the river bottom at Big Bend , Texa s, up to 1,6 50 m elevation (Borell and Bryant , 1942).In Trans-Pecos Texas, it occur s from 540 to 1,8 30 m, but is most common at elevations between 1,050 and1,6 50 m (Schmidly, 19 77 a) .The escarpment of the Sierr a del Carm en-Sierra Madre Oriental act s as a barrier on the eastern side of the range.The southern distribut ional limit is near latitud e 25°N along the southern Coahuila-Rio Nazas filter barri er (Schrnid ly, 1977 b).FOSSIL RECORD.The genus Ammospermoph ilus probably diverged in the Miocene and had already attained nearly modern form by Clarendonian times (James, 196 3).Specimens of A. interpr es have been recovered from prehistoric cave deposits near Cuatro Cienegas, Coahuila (Gilmore, 1947) and Cueva Quebrada, FIG.