Late Pleistocene fish fossils of Coregonus, Stenodus, Thymallus, Catostomus, Lota, and Cottus from the Old Crow basin, northern Yukon, Canada

Abstract

Fossils of the broad whitefish, Coregonus nasus; the inconnu, Stenodus leucichthys; the longnose sucker, Catostomus catostomus; and the burbot, Lota lota, are reported for the first time from North America and a freshwater sculpin, Cottus, for the first time from Yukon Territory. The known fossil occurrence of the Arctic grayling, Thymallus arcticus, in North America is extended from 32 000 to about 60 000 years BP. These six fossils represent about one sixth of the present-day Yukon freshwater ichthyofauna of 35 species.These fossils provide a major test for the method of determining glacial refugia based on geographic variation of morphological or protein characters. They confirm that these taxa were present prior to and presumably survived the Wisconsinan glaciation in a Beringian refugium.The occurrence of these fossils, all subarctic or subarctic–boreal species known at present in the same area, does not suggest a paleoenvironment greatly different from the present one.