Morphological variation, and latitudinal and altitudinal distribution of Eothenomys chinensis, E. wardi, E. custos, E. proditor, and E. olitor(Rodentia, Arvicolidae) in China.

Abstract

A total of 308 museum specimens of the genus Eothenomys from five separate areas in Sichuan (Szechwan) and Yunnan Provinces, China, were categorized by the relationship between condylobasal length (CBL) and tail length (TL). These specimens were allocated to three larger species, E. chinensis, E. wardi and E. proditor, and two smaller ones, E. custos and E. olitor. E. chinensis and E. wardi are allopatric, and their distributions separated by about 240 km in northern high mountain areas (28-30° N). E. chinensis lives at altitudes above 1500 m, whereas E. wardi was found above 2300 m. Lengths of bulla (BL), tail (TL) and hind foot (HFL) were slightly larger in E. chinensis than in E. wardi E. custos has a large latitudinal range between 26° and 29° N in Sichuan and Yunnan Provinces, whereas E. proditor occurs near the borders of Sichuan and Yunnan (27-28° N). The latitudinal range of E. custos overlaps with that of E. proditor in the areas of 26-28° N and 100-102° E, but E. custos was found at slightly higher altitudes (2500-4800 m) than E. proditor (2500-4200 m). The distance between the anterior-most point on the upper incisor to the posterior-most edge of the third upper molar (I-M3) and BL of E. custos tended to increase from south to north, whereas those of E. proditor tended to decrease. E. custos had longer tails in localities around 29° N and 101.5° E than in other areas. E. olitor was recorded from two widely separated localities (ca. 23.5° N and 99.5° E, and ca. 27° N and 104° E).