''Teleosaurus'' (from , 'perfect' and , 'lizard') is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of teleosaurid crocodyliform found in the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

Calcaire de Caen Formation of

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. It was approximately in length. 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 purpose of classifying organisms that do not fit anywhere else. They are typically defined by e ...

, 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 Scientific method, researches 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, philosophers engag ...

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 more loosely to include all extant member ...

and

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

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

Steneosaurus ''Steneosaurus'' (from , 'narrow' and , '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 wastebasket taxon for thalattosuchian ...

'') 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". Cuv ...

. 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 theorie ...

.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 (10 July 1809 – 21 December 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 i ...

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 (; ; ) is a Communes of France, commune inland from the northwestern coast of France. It is the Prefectures in France, prefecture of the Departments of France, department of Calvados (department), Calvados. The city proper has 105,512 inha ...

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

jaw The jaws are a pair of opposable articulated structures 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 ...

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 (biology), family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males ...

.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

{{Taxonbar, from=Q602028 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