Thompson called in fossil sloth experts who helped confirm that it came from a Jefferson’s ground sloth, Megalonyx jeffersonii. “Megalonyx jeffersonii … it’s just one of those iconic animals that more ...

He even wrote a scientific paper in 1796, describing what he called a Megalonyx (great claw). His conclusions were wrong but his pioneering work was honored when the giant sloth was renamed ...

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The animal, named Megalonyx by Thomas Jefferson in 1799, was the first genus of fossil named from the United States. Thought to have roamed North America during one of the last ice ages ...

Most fossils of the extinct creatures have no heads, but researchers analyzed complete fossils of juveniles and were able to ...

It’s more than a foot across.Clockwise from upper left: Adamussium Colbecki; Glyptonotus Antarcticus; Colossendeis Megalonyx; Macroptychaster sp. (sea star), Parborlasia Corrugatus and ...

Based on the fossil records and genetic studies, the three-toed sloth is related to giant ground sloths, including the elephant-sized Megatherium and pony-sized Megalonyx, which were found in Central ...

That claw didn’t belong to a fearsome meat eater, but to a massive, cumbersome sloth (Megalonyx jeffersonii). Not cute and endearing like present-day sloths in South America, these sloths were ...

As if the largest bug to ever live — a monster nearly 9 feet long with several dozen legs — wasn't terrifying enough, scientists could only just imagine what the extinct beast's head looked ...