Karyotypes of three shrew species (Soriculus nigrescens, Episoriculus caudatus and Episoriculus sacratus) from Nepal

Abstract

The karyotypes of three shrew species (Mammalia, Soricomorpha, Soricidae) from Nepal were examined for the first time. Based on the karyotypes and overall differences in skull size, the current Episoriculus caudatus appeared to include two distinct species: the larger E. caudatus and the smaller Episoriculus sacratus. Episoriculus sacratus has three subspecies, E. s. soluensis in Nepal and Sikkim, E. s. umbrinus in Assam, Myanmar and the Yunnan Province of China, and E. s. sacratus in the Sichuan Province of China. Soriculus nigrescens had a diploid chromosome number (2n) and fundamental number (FN), including two X chromosomes, of 64 and 92, respectively, consisting of 11 metacentric or submetacentric, two subtelocentric and 18 acrocentric pairs of autosomes, a metacentric X and an acrocentric Y chromosome. Episoriculus sacratus soluensis had 2n = 74 and FN = 126, consisting of 12 metacentric or submetacentric, 13 subtelocentric and 11 acrocentric pairs of autosomes, a submetacentric X and an acrocentric Y chromosome. Episoriculus caudatus had 2n = 60 and FN = 118, consisting of 19 metacentric or submetacentric, nine subtelocentric and one acrocentric pair of autosomes, a subtelocentric X and an acrocentric Y chromosome. The karyotypes of these three species are characterized by their large 2n and FN values compared with other Soricidae.