Herpetofaunas from the overburden (Quaternary) of western Canada

摘要

Quaternary herpetofaunas from eight palaeontological localities in western Canada (British Columbia: Bear Flat; Alberta: Eagle Cave, January Cave, Rat's Nest Cave, Hand/Wintering Hills, Fletcher Site, Stampede Site and Little Fish Lake) are described in detail for the first time. Identifications of taxa from these localities include frogs (Rana sp., Bufo sp., and Anura indet.), salamanders (cf. Ambystoma sp.), and snakes (cf. Thamnophis sp. and cf. Pituophis sp.). Preglacial and postglacial herpetofaunas are distinctly separated by a boundary resulting from the advance and retreat of glacial ice across northern North America. The taxonomic records presented here represent a conservative, morphology-based approach to identification that resulted in less taxonomic resolution than is commonly found in literature on Quaternary herpetofaunas. Nonetheless, the resultant data set was useful for establishing a framework that is indicative of biogeographic stability in Quaternary reptiles and amphibians of western Canada. We hypothesise that the observed stability may be related to evolutionary adaptations (e.g. cold-tolerance) in specific lineages.