The Eastern Limit of Beringia: Mammoth Remains from Banks and Melville Islands, Northwest Territories

Abstract

ABSTRACT. Two mammoth fossils (presumably woolly mammoth, Mammuthus primigenius) from northwestern Banks and southwestern Melville Islands, Northwest Territories, Canada, have been radiocarbon-dated to the Last Glacial Maximum (LGM), at 21 000 and 22 000 14 CYBP, respectively. These fossils not only are the northernmost mammoth records for North America, but also indicate that the Mammoth Steppe and Beringia extended eastward at least to Ballast Brook, Banks Island (74.3˚ N, 123.1˚ W), and possibly to the Cape James Ross area of Melville Island (75.7˚ N, 114.4˚ W). The specimens, a tibia and a tusk, probably represent woolly mammoths that moved northeastward from the Mackenzie Delta region during the LGM, when worldwide sea level had dropped about 120 m, leaving large tracts of sea bottom exposed off the Beaufort Sea coast and the west coast of Banks Island (then largely clear of glacial ice). Evidently herb tundra rich enough to supply the mammoths' needs characterized the regional landscape at that time. It is proposed that the term "Beringia" be used in the broad sense where evidence exists for a land connection between Asia and North America, regardless of its cause(s) and its supposed westerly or easterly limits, and that "Beringia" be used in a standard way: followed by its geological age in parentheses. Also, the term "Bering Isthmus" seems preferable to the commonly used "Bering Land Bridge."

Evolutionary reconstruction supports the presence of a Pleistocene Arctic refugium for a large mammal species

“…Among those, a fossilized muskoxen bone on Banks Island was dated to 34,000 YBP (Maher, ). Mammoth remains found on Banks and Melville islands were radiocarbon dated to ~21,000–22,000 YBP (Harington, ) and suggest that large mammals could have survived in refugia on Banks Island or other regions in the Arctic. However, MacPhee () pointed out that those mammoth remains could have been transported on ice rafts from the mainland and therefore, do not provide conclusive evidence to the existence of Arctic refugia.…”

Eastern Beringia and beyond: Late Wisconsinan and Holocene landscape dynamics along the Yukon Coastal Plain, Canada

“…During the Last Glacial Maximum (LGM,~22 to 19 cal ka BP), Alaska and the Yukon constituted the eastern margin of Beringia (Hultén, 1937;Harington, 2005). This unglaciated region extended westward across the Bering land bridge into Siberia when the glacio-eustatic sea level was~120 m lower than today (Fairbanks, 1989;Yokoyama et al, 2000).…”

The Muirkirk Mammoth: A Late Pleistocene woolly mammoth (Mammuthus primigenius) skeleton from southern Ontario, Canada

“…Fully-evolved woolly mammoths were present about 400,000 years ago, appearing in Europe some 150,000 years ago (Lister and Bahn, 2007, p. 29). They spread westward via the English Isthmus (land exposed during glaciations connecting mainland Europe with Britain) to the British Isles, and eastward to northwestern North America via the Bering Isthmus (Harington, 2005), following steppe and tundra-like habitat to which they were best adapted. The migration to northwestern North America (Eastern Beringia) may have occurred about 200,000e 100,000 years ago (Lister and Bahn, 2007, p. 35;Debruyne et al, 2008, p. 35).…”

“…A lamellar frequency (LF) of 10 and an enamel thickness (ET) of about 2 on a well worn sixth molar indicates that this mammoth is best referred to a woolly mammoth (M. primigenius) e one of several identified from the southern refugium (Harington and Ashworth, 1986, Fig. 3), as opposed to the Eastern Beringian refugium that existed in northwestern North America (Harington, 2005). The apparent "primitiveness" of the sixth molars (e.g.…”