Ochotona collaris (Nelson, 1893) . Proc. Biol. Soc. Washington, 8:117.

TYPE LOCALITY: "about 200 miles south of Fort Yukon, Alaska near the head of the Tanana River." [USA].

DISTRIBUTION: WC Mackenzie, S Yukon, NW British Columbia (Canada); SE Alaska (USA).

STATUS: Not significantly threatened (MacDonald and Jones, 1987).

SYNONYMS: Monotypic.

COMMENTS: Broadbooks (1965) and Youngman (1975) considered collaris and princeps conspecific. Corbet (1978c), following Argyropulo (1948) and Gureev (1964), included collaris in alpina . A statistical réévaluation of craniometric data by Weston (1981) indicated that collaris, princeps and alpina are separate species; Hall (1981:286) also recognized collaris as a distinct species. O. collaris and O. princeps share similar chromosome numbers that differ sharply from those of alpina and hyperborea (Vorontsov and Ivanitskaya, 1973) . Reviewed by MacDonald and Jones (1987, Mammalian Species, 281).