Brachygnathosuchus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of crocodilia

Crocodilia

Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...

n. Fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s have been found from the Upper Purus River in western Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. As there was no lithified strata for the original specimen to be correlated with (it was found in the silt of the riverbed), the fossils cannot be dated with any certainty. However, partial remains of different organisms found in the vicinity of the specimen, such as a possible Megamys tooth and a humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

 of a megalonychine ground sloth, suggest that they were of Pliocene

Pliocene

The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

 age. The name Brachygnathosuchus (Greek for "short jawed crocodile") refers to its characteristically broad, stout mandible

Mandible

The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...

, unusual among crocodilians. The holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 specimen was referred to Crocodilia on the basis of a partial right ramus

Ramus

Ramus can refer to:* A branch* A portion of a bone , as in the Ramus of the mandible or Superior pubic ramus* A nerve ramus such as the Dorsal ramus of spinal nerve* Petrus Ramus...

 of the lower jaw consisting of a portion of a very large dentary bone. The bone differs from those of other related fossil and modern crocodilians and was originally said to resemble that of a dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

. An eroded osteoderm

Osteoderm

Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...

 also associated with the specimen provides further evidence for its classification as a crocodilian.

External links

• Brachygnathosuchus in the Paleobiology Database
  Paleobiology Database
  ' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...