Teleosaurus Cadomensis Skull

''Teleosaurus'' (from el, τέλειος , 'perfect' and el, σαῦρος , 'lizard') is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately in length and weighed . The holotype is MNHN AC 8746, a quarter of a skull and other associated postcranial remains, while other fragmentary specimens are known. The type species is ''T. cadomensis'', but a second species, ''T. geoffroyi'' may also exist. It was previously considered a wastebasket taxon, with many other remains assigned to the genus.

History

Teleosaur remains have been known to science since at least 1758, although at first scientists believed the remains belonged to extinct crocodiles and alligators, and remains that have at one point in time been attributed to ''Teleosaurus'' (and ''Steneosaurus'') have been known to science since at least 1800. The holotype was discovered during the early 19th century by Pierre Tesson before he traded it with Lamoroux. ''Teleosaurus'' was briefly noted on by Jean Vincent Félix Lamouroux in 1820 as '' Crocodilus cadomensis'' and then he sent the specimen to Georges Cuvier. It was fully described by Cuvier in 1824, but it was not published until a year later by Étienne Geoffroy Saint-Hilaire.Geoffroy Saint-Hilaire, É. (1825) Recherches sur l’organisation des gavials. ''Mém Mus Natl Hist Nat'' 12: 97–155.

The second species attributed to ''Teleosaurus'', ''T. soemmeringii'' (now a synonym of ''T. cadomensis''), was named in 1829. In 1842, ''T. asthenodeirus'', was named. ''T. minimus'' and ''T ornati'' were named in 1852 and it is now firmly a synonym of ''T. cadomensis''. Friedrich August von Quenstedt also added ''T. lacunosae'' several years later in 1858. Eudes-Deslongchamps followed in 1868, naming the two species ''T. geoffroyi'' and ''T. gladius'' - both are based on remains destroyed in Caen in 1944. ''T. geoffroyi'', described on the basis of now destroyed mandibular fragments, was considered a valid species by Vignaud (1995), but it was made a probable synonym of ''T. cadomensis'' in 2020. Richard Owen added ''T. brevior'' and ''T. latifrons'' to ''Teleosaurus'' in 1884.R. Owen. (1884). A History of British Fossil Reptiles, Part III. 1-199

In 2019, the taxonomy of Teleosauroidea was reviewed and ''T. cadomensis'' was seen as the only valid species. The rest of the known species were absorbed into ''T. cadomensis'' or other genera. This study was published in October 2020.

Description

''Teleosaurus'' had highly elongate jaws, similar to those of a modern gharial.R. Owen (1842). Report on British fossil reptiles, part II. ''Report of the British Association for the Advancement of Science'' 11: 60-204.
It had a long, slender, body, with a sinuous tail that would have helped propel it through the water. Its forelimbs were remarkably short, and would probably have been held close to the body when swimming to improve the animal's streamlining. Unlike modern crocodilians, it lived in the open ocean, and it probably caught fish and squid with its sharp, needle-like teeth.

Known remains

''Teleosaurus cadomensis'' is known from the following specimens:

* MNHN AC 8746 (holotype): quarter of a skull and other associated postcranial remains
* NHMUK PV OR 119a: dorsal osteoderms
* NHMUK PV R 4207: dorsal osteoderms
* NHMUK PV OR 32588: dorsal, sacral and caudal vertebrae
* NHMUK PV OR 32657: femur
* NHMUK PV OR 32680: ischium
* NHMUK PV OR 33124 mandibular symphysis
* NHMUK PV OR 39788: partial rostrum
* NHMUK PV R 880 and NHMUK PV R 880a: additional casts

References

Prehistoric pseudosuchian genera
Prehistoric marine crocodylomorphs
Middle Jurassic crocodylomorphs
Jurassic reptiles of Europe
Taxa named by Étienne Geoffroy Saint-Hilaire
Fossil taxa described in 1820

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