''Atacisaurus'' 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 ...

dubious

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 ...

gavialoid Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea and Crocodyloidea. Although many extinct species are known, only the gharial ''Gavialis gangeticus'' and the false gharial ''Tomistoma schlegelii'' are ...

crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s have been found in the Grès de Carcassonne Member of the

Sables du Castrais Formation The Sables du Castrais Formation, also known as the Molasses du Castrais, is a geologic formation of Eocene (Ypresian to Bartonian) age, outcropping in the Montagne Noire, Montagne-Noire region of France.Noulet, J.-B. (1858) – Du terrain éoc� ...

Laure-Minervois Laure-Minervois is a commune in the Aude department in southern France. Population See also *Communes of the Aude department The following is a list of the 433 Communes of France, communes of the Aude Departments of France, department o ...

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 ...

that date back to the Middle

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Discovery and naming

The holotype, discovered in 1919 by M. Finestres in

and previously housed at the Société d'Etudes Scientifiques de l'Aude, is an anterior portion of a

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

which is now lost, and MHNT.PAL.2012.0.49, a partial skull from a different specimen is also known, which was donated to the History Museum of Toulouse in 1873 by Henri de Sévérac; MHNT.PAL.2012.0.49 has since been partially prepared at sometime between 1931 and 17 April 2016. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, ''A. glareae'', was named and described by Gaston Astre in 1931.Astre, G. (1931). "Les crocodiliens fossiles des terrains tertiaires sous pyrénéens". ''Bulletin de la Société d'Histoire naturelle de Toulouse''. 61: 25–71. A snout fragment from the History Museum of Tolouse was also described by Astre (1931), but can not be identified further than

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

''Atacisaurus''. A second nominal species of this genus, ''Atacisaurus crassiproratus'', was reclassified as a sebecosuchian in the 1990s, listed as cf. ''

Iberosuchus ''Iberosuchus'' (meaning "Iberian crocodile") is a genus of extinct sebecosuchian mesoeucrocodylian found in Western Europe from the Eocene. Remains from Portugal was described in 1975 by Antunes as a sebecosuchian crocodilian. This genus has on ...

'' by Ortega ''et al.'' (1996) before being recognized as distinct from ''

'' by Martin ''et al.'' (2023) and renamed ''

Dentaneosuchus ''Dentaneosuchus'' is a genus of large bodied sebecid crocodylomorph from the Middle Eocene of Issel and Réalmont (France). Originally described as ''Atacisaurus crassiproratus'', the discovery of additional remains led to it being placed i ...

''.

Classification

''Atacisaurus glareae'' has been considered synonymous with '' Pristichampsus rollinatii'', ''

Tomistoma ''Tomistoma'' is a genus of gavialid crocodilians. They are noted for their long narrow snouts used to catch fish, similar to the gharial. ''Tomistoma'' contains one extant (living) member, the false gharial (''Tomistoma schlegelii''), as well ...

'', '' Crocodylus intermedius'' and ''

Kentisuchus spenceri ''Kentisuchus'' is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from England and France that date back to the early Eocene. The genus has also been recorded f ...

''. Although currently classified within

Gavialidae Gavialidae is a family of large semiaquatic crocodilians with elongated, narrow snouts. Gavialidae consists of two living species, the gharial (''Gavialis gangeticus'') and the false gharial (''Tomistoma schlegelii''), both occurring in Asia. Man ...

, ''Atacisaurus'' has been suggested to have tentatively belonged within Tomistominae due to its resemblance to '' Megadontosuchus''.Brochu, C. A. (2013). Phylogenetic relationships of Palaeogene ziphodont eusuchians and the status of ''

Pristichampsus ''Pristichampsus'' (from , 'saw' and , 'crocodile') is a non-diagnostic and potentially dubious extinct genus of crocodylian from France and possibly also Kazakhstan that is part of the monotypic Pristichampsidae family. As the type species, ' ...

'' Gervais, 1853. ''Earth and Environmental Science Transactions of the Royal Society of Edinburgh'' 103: 521–550.

References

{{Taxonbar, from=Q117861068 Crocodilia Eocene crocodylomorphs Eocene reptiles of Europe Prehistoric pseudosuchian genera Nomina dubia