Three extinct squirrel-like species discovered: Mammals may have originated much earlier than thought

Sep 12, 2014

By Science Daily

Paleontologists have described three new small squirrel-like species that place a poorly understood Mesozoic group of animals firmly in the mammal family tree. The study, led by scientists at the American Museum of Natural History and the Chinese Academy of Sciences, supports the idea that mammals — an extremely diverse group that includes egg-laying monotremes such as the platypus, marsupials such as the opossum, and placentals like humans and whales — originated at least 208 million years ago in the late Triassic, much earlier than some previous research suggests.

The study is published today in the journal Nature.

“For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” said co-author Jin Meng, a curator in the Museum’s Division of Paleontology. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

The three new species — Shenshou luiXianshou linglong, and Xianshou songae — are described from six nearly complete 160-million-year-old fossils found in China. The animals, which researchers have placed in a new group, or clade, called Euharamiyida, likely looked similar to small squirrels. They weighed between 1 and 10 ounces and had tails and feet that indicate that they were tree dwellers.

4 comments on “Three extinct squirrel-like species discovered: Mammals may have originated much earlier than thought

  • “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

    Those “gaps” in fossil records just keep closing up, as new discoveries fill in more details!



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  • I don’t know if this would work, but as a fundraiser, perhaps RDF could get donated some realistic models of key creatures in evolution, and make a limited edition. Richard could number them like paintings and sell them for $100. Put me down for a tiktalik.



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