Atacisaurus Explained

Atacisaurus is an extinct dubious genus of gavialoid crocodylian. Fossils have been found in the Grès de Carcassonne Member of the Sables du Castrais Formation in Laure-Minervois, France that date back to the Middle Eocene.^[1]

Discovery and naming

The holotype, discovered in 1919 by M. Finestres in Laure-Minervois and previously housed at the Société d'Etudes Scientifiques de l'Aude, is an anterior portion of a mandible 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;^[2] MHNT.PAL.2012.0.49 has since been partially prepared at sometime between 1931 and 17 April 2016.

The type species, A. glareae, was named and described by Gaston Astre in 1931.^[3] A snout fragment from the History Museum of Tolouse was also described by Astre (1931), but can not be identified further than cf. Atacisaurus.

A second nominal species of this genus, Atacisaurus crassiproratus, was reclassified as a sebecosuchian in the 1990s, listed as cf. Iberosuchus by Ortega et al. (1996) before being recognized as distinct from Iberosuchus by Martin et al. (2023) and renamed Dentaneosuchus.^[4]

Classification

Atacisaurus glareae has been considered synonymous with Pristichampsus rollinatii,^[5] Tomistoma,^{[6] [7]} Crocodylus intermedius^[8] and Kentisuchus spenceri.^[9]

Although currently classified within Gavialidae, Atacisaurus has been suggested to have tentatively belonged within Tomistominae due to its resemblance to Megadontosuchus.^{[10] [11]}

Notes and References

1. Jouve . Stéphane . 2016 . A new basal tomistomine (Crocodylia, Crocodyloidea) from Issel (Middle Eocene; France): palaeobiogeography of basal tomistomines and palaeogeographic consequences: A New Basal Tomistomine from France . Zoological Journal of the Linnean Society . en . 177 . 1 . 165–182 . 10.1111/zoj.12357. free .
2. Ortega . F. . Buscaloni, A.D . Gasaparini, Z. . 1996 . Reinterpretation and new denomination of Atacisaurus crassiproratus (Middle Eocene; Issel, France) as cf. Iberosuchus (Crocodylomorpha, Metasuchia) . Geobios . 29 . 3 . 353–364 . 10.1016/S0016-6995(96)80037-4 . 1996Geobi..29..353O .
3. Astre, G. (1931). "Les crocodiliens fossiles des terrains tertiaires sous pyrénéens". Bulletin de la Société d'Histoire naturelle de Toulouse. 61: 25–71.
4. Martin . J. E. . Pochat-Cottilloux . Y. . Laurent . Y. . Perrier . V. . Robert . E. . Antoine . P.-O. . 2023 . Anatomy and phylogeny of an exceptionally large sebecid (Crocodylomorpha) from the middle Eocene of southern France . Journal of Vertebrate Paleontology . 42 . 4 . e2193828 . 10.1080/02724634.2023.2193828 . 258361595 .
5. Rossmann . Torsten . 1998-11-10 . 2. Taxonomical revision of the family Pristichampsidae EFIMOV (Crocodilia: Eusuchia) . Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen . 210 . 1 . 85–128 . 10.1127/njgpa/210/1998/85 . 0077-7749.
6. Romer, A. S. (1956). Osteology of Reptiles. Chicago: University of Chicago Press
7. Kuhn, O. (1968) Die vorzeitlichen Krokodile. Munich: Oeben, Krailling bei München.
8. Berg, D. E. (1966) Die Krokodile, insbesondere Asiatosuchus und aff. Sebecus?, aus dem Eozän von Messel bei Darmstadt/Hessen. Abhandlungen des Hessischen Landesamtes für Bodenforschung 52:1-105.
9. Jouve, S. (2004). Etude des Crocodyliformes fini Crétacé-Paléogène du Bassin des Oulad Abdoun (Maroc) et comparaison avec les faunes africaines contemporaines: systématique, phylogénie et paléobiogéographie. Unpublished Ph.D. Dissertation. Paris: Muséum National d'Histoire Naturelle, 651

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10. Vasse, D. (1992).Les crocodiles de l'Aude: aperçu du matériel connu et présentation de quelques nouvelles pièces. Bulletin de la Société d'Etudes Scientifiques de l'Aude. 92: 37–41.
11. Brochu, C. A. (2013). Phylogenetic relationships of Palaeogene ziphodont eusuchians and the status of Pristichampsus Gervais, 1853. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 103: 521–550.