A group of fossil ivory hunters found the carcass of a well-preserved bird in the permafrost near the village of Belaya Gora in northeast Siberia. The first thing these group of hunters thought was that the bird was dead for a day or two but it turns out it was about 46,000 years old. A relict from the middle of the last Ice Age.
Scientists at the Swedish Museum of Natural History determined that the Ice Age specimen was an ancestor of the horned lark. Horned larks are usually found in open habitats, according to experts, this "ice bird" was female and probably died non-violently before it ending up freezing, a fate that prevented it from decomposing for a thousand years.
It is the first bird to be taken from the permafrost deposits of the Ice Age.
In recent years, the permafrost areas of the Arctic have revealed a large number of frozen animal carcasses from the last Ice Age, including mammoths, woolly rhinos, horses or bison, but this is the first time a bird has been found. These remains are of great interest to palaeontology, as they allow a better understanding of the impact of climate change on species, populations and communities.
Examining the specimen
The scientists used 50 mg of the bird's tissue for DNA extraction and genome sequencing. They reconstructed its mitogenome and extracted a partial COI gene, which is used for species identification. They searched GenBank's bird genetic databases for a match with this gene and found a 100% identity match with the Horned Lark (Eremophila alpestris), a species of lark from the Alaudidae family found throughout the northern hemisphere.
"Not only can we identify the bird as a horned lark, but genetic analysis also suggests that the bird belonged to a population that was a joint ancestor of two subspecies of horned larks living today, one in Siberia and the other in the steppe in Mongolia," says Nicholas Dussex of Stockholm University and co-author of the paper.
During the last Ice Age, the giant steppe spread over northern Europe and Asia. The steppe was home to currently extinct species such as the woolly mammoth and the woolly rhinoceros. One theory states that the giant steppe was divided into the biotopes we know today: tundra in the north, taiga in the middle and steppe in the south.
"Our results support this theory, as the diversification of the horned lark into these subspecies seems to have occurred at the same time as the giant steppe disappeared," says Love Dalén, a professor at the Swedish Museum of Natural History and a leading researcher at the Centre for Paleogenetics.
Reference: Nicolas Dussex, David W. G. Stanton, Hanna Sigeman, Per G. P. Ericson, Jacquelyn Gill, Daniel C. Fisher, Albert V. Protopopov, Victoria L. Herridge, Valery Plotnikov, Bengt Hansson, Love Dalén. Biomolecular analyses reveal the age, sex and species identity of a near-intact Pleistocene bird carcass. Communications Biology, 2020; 3 (1 ) OJI: 10.1038/s42003-020-0806-7