Canis edwardii
Introduction '''''Canis edwardii''''', also known as '''Edward's wolf''', is an extinct species of wolf in the genus ''Canis'' which was endemic to North America three million years ago from the Late Blancan stage of the Pliocene epoch and was extinct by the end of the Irvingtonian stage of the Pleistocene epoch. Timeline of ''Canis edwardii'' in red
Taxonomy ''Canis edwardii'' was named by Gazin in 1942.Xiaoming Wang and Richard H. Tedford proposed that the genus ''Canis'' was the descendant of the coyote-like ''Eucyon davisi'' and its remains first appeared in the Miocene (6 Mya) in the Southwestern USA and Mexico. By the Pliocene (5 Mya), the larger ''Canis lepophagus'' appeared in the same region, and by the Early Pleistocene (1 Mya) ''Canis latrans'' (the coyote) was in existence. They proposed that the progression from ''Eucyon davisi'' to ''C. lepophagus'' to the coyote was linear evolution. Additionally, ''C. edwardii'', ''C. latrans'', and ''C. aureus'' thought to have formed a small clade together and because ''C. edwardii'' appeared earliest, spanning the mid-Blancan (late Pliocene) to the close of the Irvingtonian (late Pleistocene) it is proposed as the ancestor.===''Canis priscolatrans''===''Canis priscolatrans'' lived in the Late Pliocene-Early Pleistocene in North America. The first definite wolf appeared in the Late Blancan/Early Irvingtonian, and named ''C. priscolatrans'' that was either very close to or a synonym for ''Canis edwardii''. It resembled ''C. rufus'' in cranial size and proportions but to more complex dentition. However, there are no fossils of ''C. rufus'' until the Late Rancholabrean.Björn Kurtén was uncertain if ''C. priscolatrans'' derived from ''C. lepophagus'' and ''C. arnensis'', but believed that ''C. priscolatrans'' was a population of large coyotes that were ancestral to Rancholabrean and recent ''C. latrans''. He noted that ''C. arnensis'' of Europe showed striking similarities to ''C. priscolatrans'', and they could represent what once was a holarctic population of coyotes. Ronald Nowak disagreed, and believed that ''C. priscolatrans'' was a counterpart to the European ''C. etruscus''. Kurtén later proposed that both ''C. priscolatrans'' and ''C. etruscus'' were part of a group which led to ''C. lupus'', but was not sure if they evolved separately from ''C. lepophagus'' or a possible common ancestor that was derived from ''C. lepophagus''.The remains of the larger coyote-like ''C. edwardii'' have been found in the later Pliocene in the Southwestern USA along with ''C. lepophagus'', which indicates a descent. Tedford recognised ''C. edwardii'' and found that the craniodental morphology of ''C. priscolatrans'' fell inside that of ''C. edwardii'' such that the species name ''C. priscolatrans'' was doubtful (''nomen dubium''). In 2021, researchers sequenced the nuclear DNA (from the cell nucleus) of the dire wolf. The sequences indicate the dire wolf to be a highly divergent lineage which last shared a most recent common ancestor with the wolf-like canines 5.7 million years ago, with morphological similarities with the grey wolf being convergent evolution. The study's findings are consistent with the previously proposed taxonomic classification of the dire wolf as genus ''Aenocyon''. The study proposes an early origin of the dire wolf lineage in the Americas, and that this geographic isolation allowed them to develop a degree of reproductive isolation since their divergence 5.7 million years ago. Coyotes, dholes, gray wolves, and the extinct ''Xenocyon'' evolved in Eurasia and expanded into North America relatively recently during the Late Pleistocene, therefore there was no admixture with the dire wolf. The long-term isolation of the dire wolf lineage implies that other American fossil taxa, including ''C. armbrusteri'' and ''C. edwardii'', may also belong to the dire wolf's lineage.
Description ''C. edwardii'' was larger than ''C. latrans'' and differs in skull and some tooth proportions. , under this idea ''C. edwardii'' was a modest sized canid. A study of isotopes showed ''C. edwardii'' had a dietary overlap with the saber toothed cat ''Smilodon gracilis'', the large size of ''Smilodon gracilis'' and its similar sized prey implied ''C. edwardii'' might have hunted in packs due to the size of the prey included in the study.
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