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Gryposuchus
''Gryposuchus'' is an extinct genus of gavialoid crocodilian. It is the type genus of the subfamily Gryposuchinae. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed during the early and middle Miocene epoch. One recently described species, ''G. croizati'', grew to an estimated length of .
==Species==
The type species of ''Gryposuchus'' is ''G. neogaeus''. Specimens from this species were first described from Argentina in 1885, although it was referred to ''Ramphostoma'' at the time.〔Burmeister, G. (1885). Examen crítico de los mamíferos y los reptiles denominados pot Don Augusto Bravard. ''Anales del Museo Púbtico de Buenos Aires'' 3: 95-173.〕 It was assigned to the current genus in 1912 along with a newly described species, ''G. jessei''.〔Gurich, G. (1912). ''Gryposuchus jessei'', ein neues schmalsnauziges Krokodil aus den jungeren Ablagerungen des oberen Amazonas-Gebietes. ''Jahr. Hamburg. Wissensch. Anst.'' 29:59-71.〕〔Cozzuol, M. A. (2006). The Acre vertebrate fauna: Age, diversity, and geography. ''Journal of South American Earth Sciences'' 21:185-203〕
Another species, ''G. colombianus'', has been recovered from deposits in Colombia that date back to the Miocene and Pliocene epochs. This species, named in 1965, was originally referred to ''Gavialis''.〔Langston, W. (1965). Fossil crocodilians from Colombia and the Cenozoic history of the Crocodilia in South America. ''University of California Publications in Geological Sciences'' 52:1–152.〕 Fragmentary material of ''Gryposuchus'' from the Fitzcarrald Arch in the Peruvian Amazon dating back to the late middle Miocene bear a close resemblance to ''G. colombianus'', but differ in rostrum proportions.〔Salas-Gismondi, R., Antoine, P. O., Baby, P., Brusset, S., Benammi, M., Espurt, N., de Franceschi, D., Pujos, F., Tejada, J. and Urbina, M. (2007). Middle Miocene crocodiles from the Fitzcarrald Arch, Amazonian Peru. ''In:'' Díaz-Martínez, E. and Rábano, I. (eds.), ''4th European Meeting on the Palaeontology and Stratigraphy of Latin America'' Cuadernos del Museo Geominero, nº 8. Instituto Geológico y Minero de España, Madrid.〕
A new species, ''G. croizati'', found from the upper Miocene Urumaco Formation in northwestern Venezuela, can be distinguished from other species of ''Gryposuchus'' on the basis of a reduced number of maxillary teeth, a slender parietal interfenestral bar, and widely separated and reduced palatine fenestrae, among other things. Based on measurements of the orbital cranial skeleton, the length of the animal has been estimated at around 10.15 m in length, with a total mass of about 1745 kg. Measuring the entire length of the skull from the end of the rostrum to the supraoccipital would result in a much larger size estimate, up to three times as great. However, because there is considerable variation seen in rostral proportions among crocodilians, the latter measurements are probably not an accurate way of estimating body mass and length.〔Riff, D. and Aguilera, O. A. (2008). The world's largest gharials Gryposuchus: description of ''G. croizati'' n. sp. (Crocodylia, Gavialidae) from the Upper Miocene Urumaco Formation, Venezuela. ''Paläontologische Zeitschrift'' 82(2):178-195.〕 Despite this, the species is still one of the largest crocodilians known to have existed, and it may indeed have been the largest gavialoid to have ever existed if a recent revision in the estimated size of the large tomistomine ''Rhamphosuchus'' is correct (the genus was once considered to be 15 m in length; the new estimate puts it at approximately 10 m).〔Head, J. J. (2001). Systematics and body size of the gigantic, enigmatic crocodyloid ''Rhamphosuchus crassidens'', and the faunal history of Siwalik Group (Miocene) crocodylians. ''Journal of Vertebrate Paleontology'' 21(Supplement to No. 3):59A.〕
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