''Teleosaurus'' (from el, τέλειος , 'perfect' and el, σαῦρος , 'lizard') is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

teleosaurid Teleosauridae is a family of extinct typically marine crocodylomorphs similar to the modern gharial that lived during the Jurassic period. Teleosaurids were thalattosuchians closely related to the fully aquatic metriorhynchoids, but were less ad ...

crocodyliform found in the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

Calcaire de Caen Formation of

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. 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 Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...

, with many other remains assigned to the genus.

History

Teleosaur remains have been known to science since at least 1758, although at first

scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, ...

s believed the remains belonged to extinct

crocodiles Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant memb ...

and

alligators An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...

, and remains that have at one point in time been attributed to ''Teleosaurus'' (and ''

Steneosaurus ''Steneosaurus'' (from el, στενός , 'narrow' and el, σαῦρος , 'lizard') is a dubious genus of teleosaurid crocodyliform from the Middle or Late Jurassic ( Callovian or early Oxfordian) of France. The genus has been used as a w ...

'') 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 Jean Vincent Félix Lamouroux (3 May 1779 – 26 March 1825) was a French biologist and naturalist, noted for his seminal work with algae. Biography Lamouroux was born in Agen in the Aquitaine of southwestern France, the son of Claude Lamouroux, ...

in 1820 as '' Crocodilus cadomensis'' and then he sent the specimen to

Georges Cuvier Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuvier ...

. It was fully described by Cuvier in 1824, but it was not published until a year later by

Étienne Geoffroy Saint-Hilaire Étienne Geoffroy Saint-Hilaire (15 April 177219 June 1844) was a French naturalist who established the principle of "unity of composition". He was a colleague of Jean-Baptiste Lamarck and expanded and defended Lamarck's evolutionary theories. ...

.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 Friedrich August von Quenstedt (July 10, 1809 – December 21, 1889), was a German geologist and palaeontologist. Life Von Quenstedt was born at Eisleben in Saxony, and educated at the Humboldt University of Berlin. After a period as assistant ...

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 Caen (, ; nrf, Kaem) is a commune in northwestern France. It is the prefecture of the department of Calvados. The city proper has 105,512 inhabitants (), while its functional urban area has 470,000,Teleosauroidea Teleosauroidea is an extinct superfamily of thalattosuchian crocodyliforms living from the Early Jurassic to the Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier o ...

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. Crystal Palace Teleosaurus

Description

''Teleosaurus'' had highly elongate

jaw The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth and serv ...

s, similar to those of a modern

gharial The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...

.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 {{paleo-archosaur-stub