New Ichthyosaur Found In Museum
Museum collections are a treasure trove of fossil specimens. In fact there are countless discoveries waiting to be made without having to go into the field just by casting a careful eye over existing collections.
That is exactly what Paleontologist Dean Lomax did in 2008. He noticed that an alleged plaster copy of a fossil specimen of an ichthyosaur was actually an original fossil. Upon further examination of the anatomical details, he discovered that the fossil is also a previously unknown species of ichthyosaur, now named Ichthyosaurus anningae (after Mary Anning who discovered ichthyosaurs).
Ichthyosaurs are a group of large aquatic reptiles living during the time of the dinosaurs. They lived from about 250 to 90 million years ago, going extinct about 25 million years before the dinosaurs. Their name means fish lizard. They superficially resemble a tuna in shape, streamlined as an ocean predator.
The specimen examined by Lomax is preserved in great detail, down to its last meal of squid. Lomax was able to identify anatomical features that distinguish the specimen from other ichthyosaur species.
Ichthyosaurs were a diverse group. Although it is not known what their closest land vertebrate ancestor was, over their 160 million year time on Earth you can see a general trend in their evolution from a lizard-like body plan to a fish-like body plan.
One dramatic change was in the forelimb bones. This started out as a typical lizard hand, but over time the thumb was lost, extra digits were added, and the number of bones increased dramatically in a “corn cob” pattern.
The new species adds to the diversity of the ichthyosaurs, which are a fascinating group of extinct animals.