Shuvosaurus (meaning "Shuvo's lizard") is a genus of beaked reptile from the Late Triassic of Texas. It was described by Sankar Chatterjee in 1993 after it was discovered by his son Shuvo. It was initially interpreted as a Triassic member of the Cretaceous dinosaur family Ornithomimidae. However, the recent discovery of the related Effigia from Ghost Ranch shows that Shuvosaurus is more closely related to crocodilians, and that similarities between this animal and ornithomimids result from convergent evolution. Additionally, this discovery demonstrated that the taxon Chatterjeea was synonymous with Shuvosaurus.

 Репродукции (1, 2, 3):

 Ископаемые останки:

Tags: Вымершие рептилии, Триас, архозавроморфы, архозавры, диапсиды, круротарзы, попозавройды, равизухии, шувозавриды

(Leave a comment)

 Effigia was an archosaur that lived in what is now New Mexico. The 2 meter (6 ft) fossil was collected by Edwin H. Colbert in blocks of rock from the Ghost Ranch Quarry, which were excavated in 1947 and 1948. However, Colbert did not think any large vertebrates besides basal theropod dinosaurs were present in the quarry and as such did not even open the jackets of most of the blocks that were returned to the American Museum of Natural History.

 The fossil was rediscovered in January 2006 by graduate student Sterling Nesbitt at the American Museum of Natural History. Nesbitt was opening jackets of blocks in order to find new specimens of Coelophysis. Upon finding the remains of Effigia, he instantly recognized this was not a dinosaur and proceeded to track down the rest of the blocks from that area of the quarry. Nesbitt and Mark Norell, curator at the museum, named it Effigia okeeffeae in January 2006 after Georgia O'Keeffe, who spent many years at Ghost Ranch (her ashes are scattered there).

 Effigia is remarkable for its extreme similarity to ornithomimid dinosaurs. Nesbitt, in 2007, showed that Effigia was very similar to Shuvosaurus, and is definitely a member of the crurotarsan group Suchia (in the line leading towards modern crocodilians), and that its similarity to ornithomimids represents a case of "extreme" convergent evolution. Nesbitt also demonstrated that Shuvosaurus was the same animal as Chatterjeea, and that it belonged to an exclusive clade containing closely related suchians such as Shuvosaurus and Poposaurus (Poposauridae). Within this group, Effigia forms an even more exclusive clade with Shuvosaurus and the South American Sillosuchus (Shuvosaurinae). In 2007, Lucas and others suggested "Effigia" was synonymous with "Shuvosaurus" and used the new combination "Shuvosaurus okeeffeae" for the animal.

 Shuvosauridae is an extinct family of theropod-like pseudosuchian within the clade Poposauroidea. Shuvosaurids existed in North (USA) and South America (Argentina) during the Late Triassic period (late Carnian to Rhaetian stages). Shuvosauridae was named by Sankar Chatterjee in 1993 to include the genus Shuvosaurus.

 In a 2007 study Chatterjeea was demonstrated to be a junior synonym of Shuvosaurus, and the therein cladistic analysis found that Shuvosaurus, Effigia and Sillosuchus all form a closely related group. However, this group was left nameless, and simply referred to as Group Y. However, in accordance with ICZN rules of naming priority Shuvosauridae has priority over Chatterjeeidae (Shuvosauridae being named in 1993, while Chatterjeeidae was named in 1995). In 2011, Sterling J. Nesbitt proposed a new definition to this clade: "The least inclusive clade containing Shuvosaurus inexpectatus Chatterjee, 1993, and Sillosuchus longicervix Alcober and Parrish, 1997".

 Репродукции (1, 2, 3, 4):

Tags: Вымершие рептилии, Триас, архозавроморфы, архозавры, диапсиды, круротарзы, попозавройды, равизухии, шувозавриды

(Leave a comment)