Evidence for the teleosaurid crocodylomorph genus Machimosaurus in the Kimmeridge Clay Formation (Late Jurassic) of England |
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Authors: | Mark T Young Lorna Steel |
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Institution: | 1. School of Biological Sciences, The King's Buildings, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, UK;2. School of Ocean and Earth Sciences, National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UKzoologika@gmail.com;4. Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK |
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Abstract: | We report the only definite specimen of the teleosaurid crocodylomorph genus Machimosaurus from the Kimmeridge Clay Formation of England. This specimen (an isolated tooth) is now the only evidence of Machimosaurus in the Kimmeridge Clay Formation because a large skull and mandible, previously considered to be of Machimosaurus mosae, was recently shown to pertain to a metriorhynchid crocodylomorph. The tooth described herein was originally figured in 1884 as a tooth crown from a metriorhynchid crocodylomorph. However, its conical shape, blunt apex and distinctive enamel ornamentation are characteristic of the teleosaurid genus Machimosaurus. That Machimosaurus, and teleosaurids in general, were so rare in the Kimmeridge Clay Formation suggests that these marine crocodylomorphs did not commonly use this seaway. Their rarity is in contrast to contemporaneous deposits from continental Europe where teleosaurid remains, including Machimosaurus, are far more common. These continental deposits were deposited in shallow-marine/brackish ecosystems, suggesting that teleosaurids were largely restricted to coastal marine environments. |
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Keywords: | Crocodylomorpha England Kimmeridge Clay Formation Kimmeridgian Teleosauridae |
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