STL Science Center

STL Science Center

15 March 2013

Remembering Mary

©Heinrich Harder
In the early 19th century, 1811, Joseph and Mary Anning, young adults of Lyme Regis, Dorset, England, were exploring their world when young Joseph turned up a rather fish-like reptilian skull. A little less than a year later Mary discovered the rest of the skeleton and Ichthyosaurus, along with Mary Anning (but not so much Joseph), became one of the more important paleontological discoveries of the early 1800's; though she did not gain much notoriety until after her 1847 death. Mary Anning is typically remembered as the woman that discovered the first Plesiosaurus (which was described concurrently with Ichthyosaurus in 1821), and she is, but before that, the first skeleton she ever found, was of the Jurassic "Fish Lizard" Ichthyosaurus communis; described and properly named as a genus in 1821 by De la Beche and Conybeare and first described as a species in 1822 by Conybeare. Ichthyosaurus, as a genus, is comprised of four species; I. communis Conybeare, 1822; I. intermedius Conybeare, 1822; I. breviceps Owen, 1881; I. conybeari Lydekker, 1888. There is a lot of interesting history surrounding Ichthyosaurus and, despite the fact that this is a European fossil and not a fossil of the Western Interior Seaway (as the rest of this special month has been), it is a very important marine reptile that was reptilian king of the sea before some of the WIS inhabitants had even begun evolving, as we shall see in the next week

The typical Ichthyosaurus, to give shape to the animal before we do a lot history or behavior, would have been about 6.6ft (2m) long tip to tail. It would have been fairly fast as its dolphin shaped body suggests and probably hunted squid rather than fast fish. Integument impressions from German fossils suggest that Ichthyosaurs had large dorsal (back) fins and a fairly large caudal (tail) fin to propel it through the water. It had large sensitive eyes and sensitive ears as well, breathed oxygen through lungs, not gills, and some fossils even suggest viviparity (live birth) among Ichthyosaurs. Ichthyosaurs were most likely very graceful swimmers very in tune with their environment, some of the first highly successful reptiles to transition back to, and dominate, the ancient oceans.

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