New ice age bovine species discovered in Siberian cave

Popular Science reports on a study in Current Biology that identifies a previously unknown bovine species from bones found in Denisova Cave. The animal belongs to a lineage related to modern yaks and probably went extinct around 27,000 years ago.

Researchers generated 20 ancient genomes from the bones, spanning about 200,000 years of history. Comparing those genomes with other bovines pointed to a distinct species. The study estimates that the lineage began splitting from modern yaks about 400,000 years ago and became fully separate around 250,000 years ago.

"This age overlaps with a particularly strong warm climatic period, which could have prompted population isolation and, ultimately, speciation," said Alexandre Gilardet, a study co-author and PhD student at the Centre for Palaeogenetics in Sweden.

The remains came from Denisova Cave and the broader Altai-Sayan Mountains region in southern Siberia. The species' closest living relatives are yaks, which today live at higher elevations on the Tibetan Plateau.

Denisova Cave is already known for the Denisovans, an archaic human group discovered from a single fossil found there in 2010. The new find, said study co-author and paleogeneticist Love Dalén, "highlights the Altai region as a possible biodiversity hotspot and refugium across Ice Ages."

The researchers found no evidence that this species interbred with other bovines in the area, such as steppe bison or aurochs, the extinct wild ancestor of cattle. Instead, a population replacement likely took place during the last interglacial warm period, about 130,000 to 115,000 years ago, with a loss of genetic diversity.

"This could reflect the genetic consequences of climate warming around 120,000 years ago on a cold-adapted species," said Jonas Oppenheimer, a study co-author and paleogeneticist. "The long time span of our dataset is really rare in ancient DNA, and allows us to look across whole glacial cycles to see how they might have impacted biodiversity."

The youngest specimen found by the team is about 27,000 years old. The species likely disappeared sometime after that, but the exact timing and cause of extinction remain unknown. The genetic evidence alone is not enough to formally classify the animal as a new named species, so the team plans to compare its results with previously described yak-like remains from the same region.

• Current Biology
• Denisova Cave
• Love Dalén
• paleogenetics
• Pleistocene
• yak