Lower Jurassic Ichthyosaur

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This almost complete skeleton of a Lower Jurassic ichthyosaur, Ichthyosaurus communis Conybeare, is from the Lower Lias rocks of the Lower Jurassic at Bickmarsh on the Worcestershire/Warwickshire borders and is one of the most popular and finest specimens in Worcester City Museum’s large geological collection. It is currently on display in Worcester City Art Gallery & Museum.

The fossil was given to the Museum in 1887 as part of a bequest from the late Canon A.H. Winnington Ingram. The bequest also included two other almost complete mounted ichthyosaur specimens as well as other Jurassic fossils. Arthur Henry Winnington Ingram (1818-1887) was born at Ribbesford, Worcestershire. He was rector at Clifton-upon-Teme, and then at Harvington, and was made Honorary Canon of Worcester in 1854. He was a typical example of a multi-talented Victorian being amongst other things, a traveller, antiquary, astronomer, poet and geologist.

The moderately large and surprisingly varied fossil vertebrate collection at Worcester Museum contains scientifically interesting material and has been used by researchers for over a century. Between 1969-71 it was listed by J.B. Delair, (Caledonian Land Services, Oxford.) In 1974 Christopher McGowan of Ontario University studied the Liassic ichthyosaur material and one of the specimens, Stenopterygius sp. is figured in the resulting paper (McGowan, C. 1978. Further Evidence for the wide Geographical Distribution of Ichthyosaur Taxa. Journal of Palaeontology, Vol 52, No. 5, p. 1158, pl 2 fig 3).

Ichthyosaurs looked very like dolphins, living sea mammals, apart from their tail and an extra pair of fins. Their similarity in shape suggests they had a similar life style. With their superbly streamlined bodies, fins, flippers and long narrow jaws packed with sharp teeth, they were perfectly designed as hunter killers.

They were very fast swimmers and possibly were capable of reaching speeds of 15 mph. Information gained from analysing fossil ichthyosaur stomachs and coprolites (droppings) shows that their main diet was fish, ammonites, nautiloids and squid. The hard hooks found on the tentacles of squids were indigestible and collected in the stomach. One fossil ichthyosaur showed that it had gulped down at least 1,500 squids in its lifetime!

The largest ichthyosaurs were about 7.6m (25 feet) long but some species were no longer than a human. Ichthyosaurs swam by moving their powerful tails from side to side. When the first fossil ichthyosaur skeletons were discovered it was thought they had broken tails. Then it was realised that the backbone actually had a downward kink, and this shape supported a vertical tail fin (unlike the horizontal one found in dolphins and whales). The dorsal fin and paddles were used for steering. The skull of the ichthyosaur had a long narrow snout and the nostrils were placed far back on the sides of the head to allow the animal to feed and breathe at the same time. Ichthyosaurs had huge eyeballs that were strengthened by a ring of bones. In life the ring prevented distortion of the eyeballs when the animal was diving. Beside their fish-shaped body, many other features of the ichthyosaur indicated that they alone amongst the reptiles were totally adapted to a marine life. This included giving birth to live young in the water.

In Britain, fossil reptile remains, including those of ichthyosaurs, attracted the attention of collectors from a very early period in the study of natural history. The earliest illustrations now known to be ichthyosaurs appeared in Lithophylacii Britainnici Ichnographicia (1699), the first book devoted solely to British fossils.

Mary Anning (1799-1847) was famous for the fossils she collected close to her home in Lyme Regis. Between 1810 and 1812 she and her brother excavated a complete ichthyosaur which was 17 ft long with a 4 ft skull. They sold it for about £23 and it was deposited in William Bullock’s London Museum of Natural History in Piccadilly. Quarrying operation during the 19th century revealed many specimens of ichthyosaurs and reports of these striking finds often caused excitement among the general public. Interest was reflected in the publication of cartoons and poems.

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