Browsing by Author "Zazula, Grant D."
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Item The first Tertiary fossils of mammals, turtles, and fish from Canada's Yukon. (American Museum novitates, no. 3943)(American Museum of Natural History., 2019-10-31) Eberle, Jaelyn.; Hutchison, J. Howard (John Howard), 1939-; Kennedy, Kristen.; Koenigswald, Wighart von.; MacPhee, R. D. E.; Zazula, Grant D.Despite over a century of prospecting and field research, fossil vertebrates are exceedingly rare in Paleogene and Neogene rocks in northern Canada's Yukon Territory. Here, we describe the first records of probable Neogene vertebrate fossils from the territory, including tooth fragments of a rhinocerotid, a partial calcaneum of an artiodactyl, shell fragments of the pond turtle Chrysemys s.l. and tortoise Hesperotestudo, and a fragment of a palatine of Esox (pike). Although the tooth fragments cannot be identified solely by traditional paleontological means, we use tooth enamel microstructure, and primarily the presence of vertical Hunter-Schreger bands, to refer them to the Rhinocerotidae. As the only known record of the Rhinocerotidae in North America's western Arctic, the tooth fragments from the Wolf Creek site support the hypothesis that the clade dispersed between Asia and North America across Beringia. The fossils are consistent with a Miocene age for the Wolf Creek site that is inferred from radiometric dates of the Miles Canyon basalt flows in the vicinity of the fossil locality. Further, the tortoise and pond turtle fossils indicate a mild climate in the Yukon at the time, consistent with the vegetation reconstructions of others that indicate a warmer, wetter world in the Miocene than today.Item Osteological assessment of Pleistocene Camelops hesternus (Camelidae, Camelinae, Camelini) from Alaska and Yukon. (American Museum novitates, no. 3866)(American Museum of Natural History., 2016-10-19) Zazula, Grant D.; MacPhee, R. D. E.; Hall, Elizabeth (Paleontologist); Hewitson, Susan.During the past century, fossils of Pleistocene camels have been occasionally reported from unglaciated regions of Alaska and Yukon (collectively known as eastern Beringia), yet detailed descriptions of these materials are limited or lacking altogether. The detailed osteological treatment presented here establishes that these fossils are virtually indistinguishable from the species Camelops hesternus, a common member of Blancan to Rancholabrean faunas and known best from temperate regions of western North America. Metrically, high-latitude members of C. hesternus seem to have been smaller bodied than representatives from more southerly parts of the species range, a finding that is consistent with body-mass differences among populations of other large mammals whose ranges extended into the far north. The presence of C. hesternus in Alaska and Yukon was likely episodic, limited to relatively warm intervals such as the Last Interglaciation (Sangamonian).