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4. DIETS OF ICHTHYOSAURS

We know diets of some ichthyosaurs from the stomach contents preserved in fossils. Since not every fossil comes with good stomach contents, our knowledge is limited to some fish-shaped ichthyosaurs.

As early as 1853, Coles noticed that there were unusual structures preserved in the trunk region of ichthyosaurs (figure below). He thought they might have been the scales of ichthyosaurs, but later scientists realized that these were indeed hooklets of squid-like creatures (extinct dibranchiate cephalopods, mostly belemnites).

Since then, there have been several good studies on ichthyosaurian stomach contents, which revealed that many fish-shaped ichthyosaurs relied heavily on ancient kin of squids for their foods. Even Temnodontosaurus, a large Jurassic ichthyosaur that sometimes reached 10 meters in body length, had preference for squids, although it probably ate large vertebrates from time to time. Beside squid-like creatures, ichthyosaurs ate fish and other marine organisms.

In short, many fish-shaped ichthyosaurs were squid eaters, as in some whales today.

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Last updated on November 15, 2000