Riohasaurus (sometimes a rioiazavr , rioiazavr ) - a genus of herbivorous dinosaurs of the order of sauropodomorphs , discovered by Jose Bonaparte in the Argentine province of La Rioja . The Riohasaurus lived in the late Triassic period and reached a length of 10 meters [2] . He is the only member of his family whose remains are found in South America.
| † Riohasaurus | ||||||||||||||||
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 Riohasaurus Skull Cast | ||||||||||||||||
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| R. incertus Bonaparte, 1969 [1] |
Content
Description
The Riohasaurus was distinguished by a heavy body, bulky legs and a long neck and tail. The bones of his legs were too massive and dense for an early sauropodomorph [2] . In contrast, his vertebrae had cavities for weight relief, and, unlike most early sauropodomorphs, the riochasaurus had four sacral vertebrae instead of three [2] . All this indicated that he was a slow animal and could not stand behind his hind legs [2] [3] . The almost equal length of the front and hind limbs [2] also indicated its exclusively four-legged way of movement. However, in 2016, when studying the anatomy of the hand, Scott Hartman discovered that the lizard brushes were turned inward and the shoulder girdle is extremely inactive. This indicates that the Riohasaurus was bipedal [4] .
The very first skeleton of the Riohasaur was found without a skull [5] , but the excellently preserved skull attributed to the Riohasaur was found later [6] . The teeth of the dinosaur had a leaf-shaped and grooves. The upper jaw contained 5 front teeth and 24 following them in a row, which ended under the orbits.
Systematics
Many researchers believe that the Riohasaurus was the closest relative of the melanorosaurus , which lived from the end of the Triassic to the early Jurassic . However, studies at Bristol University have revealed a number of unique key features, such as long bones in the neck. This greatly distinguishes the Riohasaur from other dinosaurs found in the Los Colorados formation in Argentina [7] . Due to their size and anatomy of the limbs, the riochasaurus and possibly the associated melanorosaurus are considered as the closest relatives of the early sauropods [2] .
Notes
- ↑ JF Bonaparte . (1969) Dos nuevas "faunas" de reptiles triasicos de Argentina [Two new reptilian "faunas" of the Argentine Triassic]. Gondwana Stratigraphy (IUGS Symposium, Buenos Aires) 2: 283-306.
- ↑ 1 2 3 4 5 6 "Riojasaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. The Age of Dinosaurs . Publications International, LTD. p. 41. ISBN 0-7853-0443-6 .
- ↑ Van Heerden, J. and Galton, PM (1997). "The affinities of Melanorosaurus a Late Triassic prosauropod dinosaur from South Africa." Neues Jahrbuch für Geologie und Paläontologie Monatshefte . (1): 39-55
- ↑ La Rioja's ponderous biped unopened .
- ↑ Bonaparte, JF (1967). Dos nuevas "faunas" de reptiles triásicos de Argentina. Ameghiniana 10 (1): 89-102.
- ↑ Bonaparte, JF & Pumares, JA (1995). Notas sobre el primer craneo de Riojasaurus incertus (Dinosauria, Prosauropoda, Melanorosauridae) del Triasico Superios de La Rioja, Argentina. Ameghiniana 32 (4): 341-349.
- ↑ Moody, Richard. Dinofile. pg 20. Octopus Publishing Group Ltd., 2006
Literature
- Gunga HC, Suthau T, Bellman A, Friedrich A, Schwanebeck T et al. (2007). "Body mass estimations for Plateosaurus engelhardti using laser scanning and 3D reconstruction methods." Naturwiss 94