Gryposuchus

Gryposuchus is an extinct genus of gavialoid crocodilian. It is the type genus of the family 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 10m.

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. It was assigned to the current genus in 1912 along with a newly described species, G. jessei.

Another species, G. colombianus, has been recovered from deposits in Columbia that date back to the Miocene and Pliocene epochs. This species, named in 1965, was originally referred to Gavialis. 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.

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 10.15m in length, with a total mass of around 1745kg. 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. 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 15m in length; the new estimate puts it at approximately 10m).

Paleobiology
Some gryposuchines such as Siquisiquesuchus and Piscogavialis have been found from localities thought to have been deposited in coastal environments. The presence of Gryposuchus in the Urumaco Formation of Venezuela, which does include marine strata, lends credence to the idea that gryposuchines may have been living in coastal environments. However, certain localities where material from the species G. colombianus has been recovered, such as La Venta, Colombia, were clearly deposited in non-marine environments, speaking against the proposed coastal lifestyle hypothesis for all gryposuchines.