Archelon

The Archelon type specimen

I love covering extinct Turtles because they have such an interesting evolutionary history. Turtles have been around since the Triassic, dating back 220 million years. They've even had roughly the same body shape for the last 200 million of those years, with modifications being made to their teeth (losing them), their shells (going from soft to hard) and their size (varies completely!)

Today's Turtle, Archelon, definitely had a unique size. These giant Sea Turtles grew to be 12 feet long! Archelon lived during the late Cretaceous Period, and its fossils have been found primarily in South Dakota and Wyoming, which were once covered by shallow seas.

Once you get past its car-like size, you'll notice that Archelon did look quite a bit like our modern Sea Turtles. In fact, its closest living relative is the large (but not that large) Leatherback Sea Turtle. In fact, like the Leatherbacks of today, Archelon probably ate jellyfish and other soft-bodied sea creatures like squid.

Archelon did have two major differences though. The first was that its shell wasn't hard-- it was actually soft and leathery and supported by an internal bone structure. Secondly, they had remarkably broad, paddle-like flippers (modern Sea Turtles also have long flippers, but they are not nearly as broad proportionally).

They died out at the end of the Cretaceous Period, around 65 million years ago, and no Turtle since has come close to rivaling it in size!

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Status : Extinct for 65 million years
Location : North America
Size : Length around 12ft (3.6m), Weight up to 2tons

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Testudines
Family : †Protostegidae -- Genus : †Archelon -- Species : A. ischyros