Genyodectes

Snout fragment ( holotype specimen ) of Genyodectes serus

• Chubut, Argentina ( Cerro Barcino Formation)

• Genyodectes serus

Genyodectes is a genus theropod dinosaur from the group of Ceratosauria. So far, an incomplete snout is only known that was discovered in the Argentine province of Chubut and about 112 million years old is ( Aptian, Lower Cretaceous ). The only way is Genyodectes serus. Genyodectes was described in 1901 by Arthur Smith Woodward scientifically; thus it is the first undoubted non-avian theropod - which has been described from South America. The genus is characterized in particular by the very long in proportion crowns of the upper jaw.

History of Research

The snout fragment ( holotype, specimen number MLP 26-39, Museo de La Plata ) consists of the premaxillary bone ( premaxilla ), parts of both maxillae, the right and left dentary, teeth, a fragment of the left Splenials and parts of the Supra dentals. The find was the geologist Santiago Roth passed on one of his expeditions in Cañadón Grande in the Argentine province of Chubut end of the 19th century by a local gaucho. Later, the English paleontologist Sir Arthur Smith Woodward described the fossil under the name Genyodectes serus ( gr genys - " jaw, chin ," dektes - " Jaws "). However, the precise locality and thus the exact geological age of the genus remained uncertain. It was long assumed that these residues originate from the time of the uppermost Cretaceous, and more recently Genyodectes was often associated with the Abelisauriden. A recent study of the material by Oliver Rauhut (2004 ) suggests, however, that Genyodectes from the Cerro Castaño member, the lower layer member of the Cerro Barcino - formation, and thus originates in the Lower Cretaceous ( Aptian ) falls. In addition, Rauhut suggested that Genyodectes is related to the Upper Jurassic genus Ceratosaurus, so one of the Ceratosauridae.

Features

Genyodectes origin was performed as a noun dubium ( dubious name) because of the very fragmentary remains and the unclear stratigraphic long. However, the revision of the genus by Oliver Rauhut attempts to maintain the validity of the genus. According Rauhut Genyodectes to carry out its closely packed, overlapping teeth in the premaxillary bone and delimit the strongly flattened teeth of the maxilla from other genres. A common feature with Ceratosaurus were highly elongated crowns of the upper jaw, the length of which exceeded the minimum height of the lower jaw; the longest tooth crown is reconstructed with a length of 9.5 cm. In contrast to Ceratosaurus had Genyodectes 4 instead of 3 teeth in the premaxillary bone.

Documents

• Ceratosauria
• Cerato dinosaur