快猫短视频

A fossil found by fishers in Taiwan has been identified as a jawbone from the mysterious Denisovan group of ancient humans.

Denisovans were first described in 2010 from a fossil fingerbone found in Denisova cave in the Altai mountains, Russia. Although few fossils have been found, traces of their DNA still exist in some modern humans, indicating they were widespread in East Asia.

The newly identified fossil mandible was recovered from the Penghu Channel by commercial fishers while dredging the seabed. It ended up in an antique store in Tainan City, where a local resident purchased it and donated it to the National Museum of Natural Science, Taiwan.

During previous glacial periods, when sea levels were much lower, the channel was a land bridge between the mainland and Taiwan, inhabited not just by ancient humans, but also a suite of wildlife, whose fossils have also been recovered by fishers.

at the University of Copenhagen, Denmark, and his colleagues have dated the mandible based on the presence of other animal species found in the Penghu Channel. They identified two possible windows, suggesting the fossil is either between 10,000 and 70,000 years old or 130,000 and 190,000 years old. 鈥淲hich of the two windows is most likely cannot be said with certainty,鈥� says Welker.

To identify what kind of ancient hominin the bone came from, the team studied the proteins locked inside the fossil. Altogether, the researchers found 4241 amino acid residues from 51 proteins, including two protein variants that were specific to Denisovans.

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By comparing the protein sequences with other ancient humans, the researchers confirmed that the mandible belonged to a Denisovan and not a Neanderthal or a modern human.

From the enamel on a tooth, the team also recovered a variant of a protein that is coded on the Y chromosome, showing that the fossil belonged to a male.

Fossils identified molecularly as Denisovans have previously been found only in Siberia and on the Tibetan plateau, so the discovery expands the group鈥檚 known range. 鈥淭he Taiwan Strait is thousands of kilometres away. There are many fossil locations between those three sites, and so some of those fossils could be Denisovans too,鈥� says Welker.

, a team member at the Graduate University for Advanced Studies in Kanagawa, Japan, says the study suggests that a number of mysterious Chinese fossils from the Middle to Late Pleistocene are actually Denisovans.

鈥淭his is because the fossils that have been genetically confirmed to be Denisovans are mostly lacking in morphological information, and the fossils with distinct morphological features have not been examined genetically,鈥� says Tsutaya. 鈥淚n the future, if the latter fossil group is examined through the analysis of ancient proteins or ancient DNA, the evolutionary positioning of the Denisovans will become clearer.鈥�

鈥淭he elusive Denisovans are becoming more definite with every new discovery,鈥� says at Macquarie University in Sydney, Australia.

Because the fossil was found on the seabed, it is challenging to precisely date it, she says, and more fossil discoveries are needed to build up a complete picture of who the Denisovans were. 鈥淭his will help us to put together the anatomy of a species [for which] we know more about its ancient DNA and proteins than its skeleton,鈥� says Westaway.