Lay summary authored by Jack Tseng. The full paper can be read in Open Quaternary: http://doi.org/10.5334/oq.64
Beringia, the geographic region including parts of eastern Russia, Alaska, and western Yukon Territory, is scientifically important for understanding animal and human movements in and out of North America. Our current understanding of Ice Age fossil records in Beringia suggests that the region had a higher diversity of predatory mammals than at the present. However, fossils of large predator mammals are exceedingly rare, making a more complete understanding of why some species went extinct, whereas other survived, difficult.
The Old Crow region of northwestern Yukon Territory contains one of the richest Ice Age fossil deposits in Beringia and north of the Arctic Circle. The presence of Ice Age fossils has been known to First Nations people for hundreds of years. In the past century, more than 50,000 fossil specimens have been systematically collected from the Old Crow. Out of these specimens, we describe two fossils that belong to one of the rarest predators in the Beringian region, that of hyenas.
The hyena fossils we describe in this study belong to Chasmaporthetes, which is a group of wide-ranging predators known for their running-adapted limb characteristics. Prior to our study, Chasmaporthetes fossil sites between Asia and North America span more than 10,000 km, from Mongolia to southern United States. Although a Beringian route has been hypothesized for these hyenas, no physical evidence of the presence of Chasmaporthetes existed until this study confirmed two fossilized Chasmaporthetes teeth from the Old Crow. We can now say that a Beringian immigration route of Chasmaporthetes from Asia to North America is supported by the intermediate locale of Old Crow, north of the Arctic Circle.
The success of Chasmaporthetes in spreading throughout the world’s northern continents is evident from fossil records in Europe, Africa, Asia, and North America. However, the limited time duration of Chasmaporthetes in North America suggests that other predators may have competed with them there, preventing them becoming dominant. Our review of candidate competitor species indicates that giant short-faced bears and precursors of modern wolves may have been the most likely competitors of Chasmaporthetes in certain geographic regions of North America.
The extinction of Chasmaporthetes during the Pleistocene marked the end of running-adapted hunter-scavengers on the North American continent. Given the importance of scavengers to modern day African ecosystems, we speculate that the extinction of Chasmaporthetes may have changed the way the North American food webs functioned during the later Pleistocene, and into today.
Full paper: Tseng, Z.J., Zazula, G. and Werdelin, L., 2019. First Fossils of Hyenas (Chasmaporthetes, Hyaenidae, Carnivora) from North of the Arctic Circle. Open Quaternary, 5(1), p.6. DOI: http://doi.org/10.5334/oq.64