A new look at the taxonomic status of Ochotona argentata HOWELL, 1928

Abstract

The Silver Pika, Ochotona argentata, inhabits a restricted area in the Helan Shan where it occupies rocky mountainous habitat (SMITH et al. 1990). It was originally described as a subspecies of the Altai pika (Ochotona (Pika) alpina argentata) from the Helan Shan in Ningxia (former northern Gansu) by HOWELL in 1928. Additional five specimens were collected by MA Yong in 1985-1987. Close study of these materials and the type specimens supports the hypothesis that this form is a distinct species (ERBAJEVA 1997). Subsequently, N. A. FORMOZOV gathered new specimens at the type locality (FORMOZOV 1997) and showed that O. argentata possesses the same number of chromo- somes (2n = 38) as O. pallasi (BAKLUSHINSKAYA F FORMOZOV et al. 2004). YU et al. (2000) and NIU et al. (2004) referred the pikas from the Helan Shan to O. pallasi helanshanensis. A comparative analysis of O. argentata, O. alpina and O. pallasi indicates that O. argentata differs from each of the last two species by its slightly larger size, by having silvery light gray winter and bright red summer pelage, by possessing a rather robust mandibular ramus and by other dental and skull morphological traits. Moreover, the chromosome number of O. argentata and O. pallasi contrasts with the dip- loid number in O. alpina (2n = 42).