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Both the canid family and its genus Canis are thought to have originated in North America, roughly 40 and 6 million years ago, respectively. Members of both radiations subsequently emigrated to the Old World. Wolf-like species of Canis apparently originated there, and then returned to North America.:p148

In 1974 Robert A. Martin proposed that the large North American wolf C. armbrusteri (Armbruster’s wolf) was C. lupus. Nowak, Kurtén, and Annalisa Berta proposed that C. dirus was not derived from C. lupus. In 1987, a new hypothesis proposed that a mammal population could give rise to a larger form called a hypermorph during times when food was abundant, but when food later became scarce the hypermorph would either adapt to a smaller form or go extinct. This hypothesis might explain the large body sizes found in many Late Pleistocene mammals compared to their modern counterparts. Both extinction and speciation – a process by which a new species splits from an older one – could occur together during periods of climatic extremes. Gloria D. Goulet agreed with Martin, proposing further that this hypothesis might explain the sudden appearance of C. dirus in North America and, judging from the similarities in their skull shapes, that C. lupus had given rise to the C. dirus hypermorph due to an abundance of game, a stable environment, and large competitors.
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Beringian wolf
A 2010 study compared mDNA sequences of modern wolves with those from 24 ancient wolf specimens from western Europe dated between 44,000 and 1,200 years before present (YBP). The study found that the sequences could be allocated into two haplogroups. Haplogroups 1 and 2 could be found among wolves across Eurasia but only haplogroup 1 could be found in North America. The ancient wolf samples from western Europe differed from modern wolves by 1 to 10 mutations, and all belonged to haplogroup 2, indicating its predominance in this region for over 40,000 years, both before and after the Last Glacial Maximum. A comparison of current and past frequencies indicates that in Europe haplogroup 2 became outnumbered by haplogroup 1 over the past several thousand years, but in North America haplogroup 2 – including the Beringian wolf – became extinct and was replaced by haplogroup 1 after the Last Glacial Maximum. However, a 2016 study did not support the existence of two wolf haplogroups.

A scenario consistent with the phylogenetic, ice sheet size, and sea-level depth data is that during the Late Pleistocene the sea levels were at their lowest. A single wave of wolf colonization into North America commenced with the opening of the Bering land bridge 70,000 YBP. It ended with the closing of the Yukon corridor that ran along the division between the Laurentide Ice Sheet and the Cordilleran Ice Sheet 23,000 YBP during the Late Glacial Maximum. As wolves had been in the fossil record of North America but the genetic ancestry of modern wolves could be traced back only 80,000 years, the wolf haplotypes that were already in North America were replaced by these invaders, either through competitive displacement or through genetic admixture. The replacement in North America of a basal population of wolves by a more recent one is consistent with the findings of earlier studies.

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