the Fairbanks Exploration Company to collect specimens uncovered by hydraulic gold dredging near Fairbanks, Alaska. Childs Frick was a research associate in paleontology with the American Museum who had been working in the Fairbanks region. In 1930, he published an article which contained a list of "extinct Pleistocene mammals of Alaska-Yukon". This list included one specimen of what he believed to be a new subspecies which he named Aenocyon dirus alaskensis – the Alaskan dire wolf. The American museum referred to these as a typical Pleistocene species in Fairbanks. However, no type specimen, description nor exact location was provided, and because dire wolves had not been found this far north this name was later proposed as nomen nudum (invalid) by the paleontologist Ronald M. Nowak. Between 1932 and 1953 twenty-eight wolf skulls were recovered from the Ester, Cripple, Engineer, and Little Eldorado creeks located north and west of Fairbanks. The skulls were thought to be 10,000 years old. The geologist and paleontologist Theodore Galusha, who helped amass the Frick collections of fossil mammals at the American Museum of Natural History, worked on the wolf skulls over a number of years and noted that, compared with modern wolves, they were "short-faced". The paleontologist Stanley John Olsen continued Galusha's work with the short-faced wolf skulls, and in 1985, based on their morphology, he classified them as Canis lupus (gray wolf). Gray wolves were widely distributed across North American during both the Pleistocene and historic period. In 2007 Jennifer Leonard undertook a study based on the genetic, morphology, and stable isotope analyses of seventy-four Beringian wolf specimens from Alaska and the Yukon that revealed the genetic relationships, prey species, and feeding behavior of prehistoric wolves, and supported the classification of this wolf as C.lupus. The specimens were not assigned a subspecies classification by Leonard, who referred to these as "eastern Beringian wolves". A subspecies was possibly not assigned because the relationship between the Beringian wolf and the extinct European cave wolf (C. l. spelaeus) is not clear. Beringia was once an area of land that spanned the Chukchi Sea and the Bering Sea, joining Eurasia to North America. Eastern Beringia included what is today Alaska and the Yukon. Lineage Basal wolf DNA sequences can be mapped to reveal a phylogenetic tree that represents evolutionary relationships, with each branch point representing the divergence of two lineages from a common ancestor. On this tree the