Geographical variation of skull characters in pikas (Ochotona, Lagomorpha) of the alpina-hyperborea group

A multivariate analysis of 11 skull measurements, along with evaluation of the shape of maxill-premaxill suture at palatine foramina, was carried out in pikas of the alpina-hyperborea group. The study provided rational for recognition of three distinct species in this group: Ochotona alpina (Pallas, 1773), O. hyperborea (Pallas, 1811), and O. turuchanensis Naumov, 1934. O. turuchanensis is a species from central Siberia differing from O. hyperborea in the chromosome number and type of palatine foramina and from O. alpina in size of the skull. This species is allopatric with O. alpina and partly sympatric with O. hyperborea. The subspecies svatoshi is reportedly allocated to O. hyperborea. The taxonomic status of mantchurica (now allocated to hyperborea) and scorodumovi (treated at present as an isolated subspecies of O. alpina) needs careful investigation.