Finding Ophthalmosaurus – the eye lizard

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By Paul de la Salle

Ophthalmosaurus – the ‘eye lizard’ – is so called because of its enormous eyes, presumably of crucial importance when diving to enormous depths in the Jurassic seas in search and pursuit of its favourite prey, the belemnite. This was a large ichthyosaur, supremely adapted to its marine environment. Some fossil collectors think it should be called ‘Ribosaurus’ on account of the number and size of its ribs that are usually broken into hundreds of pieces when found.

Fig. 1. Block as found – 24 June 2007.
Fig. 2. Ribs.

Individual vertebrae and rib sections of this, the only ichthyosaur known from the Lower Oxford Clay, are fairly common finds. However, I was lucky enough to find a partial articulated skeleton this summer, in the drainage ditches of a Wiltshire gravel pit.

Fig. 3. Concretion before cleaning.
Fig. 4. Another concretion before cleaning.

Recent heavy rains had washed away some of the clay from the bank exposing a large pyritic concretion packed with bones, including a humerus. When I dug into the bank, I was amazed to find both front paddles, including both humeri and about 50 paddle bones. Many of the bones were fused together in life position.

Fig. 5. Front and rear flipper.
Fig. 6. The left paddle.
Fig. 7. Loose vertebrae.

Over the next week or so, I recovered quite a bit more of the skeleton but the head had been washed away by one of the floods that had deposited the gravel during the Pleistocene period. I wonder what the mammoths would have thought had they known that they were walking on top of the remains of the ‘eye lizard’.

Fig. 8. Assemble paddle.
Fig. 9. Assembled partial skeleton.

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