Denisova Cave in southern Siberia, known for discoveries linked to the extinct Denisovans, has yielded evidence of a previously unknown Ice Age bovine. Researchers identified the lineage through DNA analysis of small bone fragments, according to a study published in Current Biology.
The team examined 20 bone fragments: 14 from Denisova Cave and six from other sites in the region. The material produced 20 ancient genomes. The oldest specimen dated to roughly 250,000–200,000 years ago, while the most recent was about 27,000 years old.
The researchers say the lineage separated from the ancestors of modern yaks around 400,000 years ago. Because genetic evidence alone is not enough to formally name a new species, they refer to it provisionally as “Yak X.”
Identifying a large mammal from small, unidentifiable fragments is unusual, said study author Love Dalén, a geneticist at the Centre for Palaeogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History. Co-author Alexandre Gilardet said advances in ancient DNA research have made genetics a powerful source of information about archaeological material.
Yak X lived alongside other bovines, including the aurochs, an extinct wild ancestor of domestic cattle, and shared the Ice Age landscape with woolly mammoths, woolly rhinoceroses, horses and large predators. Dalén said its close relationship to modern yaks suggests it may have looked more like a yak than a bison.
The researchers’ samples span about 200,000 years. They suggest Yak X may have declined during a warming period around 120,000 years ago and disappeared sometime after the youngest sample, dated to 27,000 years ago. The lineage’s split from modern yak ancestors occurred around the same time as the evolutionary separation of the lineages that gave rise to present-day brown and polar bears.
Denisova Cave first became known for Denisovan remains after scientists found a finger bone there in 2008. Denisovans were extinct relatives of Neanderthals and Homo sapiens. Dalén said it was reasonable to think Yak X may have been among the animals they hunted.
The discovery adds to evidence of the diversity of large mammals in the Ice Age and of the lineages that later disappeared.
Sources: Folha Ciência.