Trigonosaurus
| Trigonosaurus | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous ( Maastrichtian ) | ||||||||||||
| 72 to 66 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Trigonosaurus | ||||||||||||
| Campos et al. , 2005 | ||||||||||||
| Art | ||||||||||||
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Trigonosaurus is a genus of sauropod dinosaurs from the Titanosauria group thatlived in what is now South Americaduring the late Upper Cretaceous ( Maastrichtian ).
So far, two very fragmentary skeletons are known that come from the Marília Formation in the Brazilian state of Minas Gerais . Other titanosaurs in this formation include Uberabatitan , Baurutitan, and Aeolosaurus .
features
As with all sauropods, it was a herbivore with a long neck and tail. The holotype specimen is estimated to be about 9.5 meters long. Compared to the contemporary Uberabatitan , Trigonosaurus was smaller and less robustly built.
Trigonosaurus can be distinguished from related genera by a combination of diagnostic features on the vertebrae: For example, the cervical vertebrae were elongated and had low spinous processes and a concave ventral edge. The middle vertebrae were also elongated, with the spinous processes sloping sharply forward. The prezygapophyses of the caudal vertebrae were enlarged anteriorly and showed broad surfaces. The connecting surfaces of the hemal arches are strongly developed from the third caudal vertebra.
Systematics
The relationship of this genus within the Titanosauria is unclear. However, it does not seem to have belonged to the most derived (most modern) titanosaurs, the Saltasaurinae , nor to the more basal (more original) titanosaurs. Salgado, Coria and Calvo (1997) see a closer relationship with Opisthocoelicaudia , which Campos and colleagues (2005) are, however, doubted. Campos and colleagues, however, see some similarities with the Aeolosaurini ( Aeolosaurus and Gondwanatitan ); so the vertebral arches are further forward on the vertebral bodies, while the spinous processes were directed obliquely forward.
Find, history of discovery and naming
The two skeletal fragments come from the Caieira site, a disused quarry about two kilometers north of Peirópolis near Uberaba . The fossils come from fine to medium-grained white to yellow sandstones that belong to the Marília Formation (Serra-da-Galga-Member), a formation of the Bauru Group . This formation is dated to the Maastrichtian , the last stage of the Upper Cretaceous .
The holotype specimen (specimen number MCT 1488-R) consists of five cervical vertebrae, ten vertebrae, the sacrum and the left ilium (ilium). The vertebrae and the last cervical vertebra were anatomically connected when they were discovered. The second specimen (Paratype, specimen number MCT 1719-R) consists of ten caudal vertebrae, which were found isolated, but probably belonged to a single individual due to their uniform size and morphology. It is possible that both specimens were a single individual. The fossils are kept in the Museu de Ciências da Terra .
The fossils were discovered by Llewellyn Ivor Price and have since been studied by various researchers (Powell, 1987; Campos and Kellner, 1999). They were listed as Peirópolis Series B , but not officially named. It was not until Diogenes de Almeida Campos and colleagues published an extensive description in 2005 and named the new genus Trigonosaurus pricei . The name Trigonosaurus ( Gr. Trigónos - "triangle", Portuguese "triângulo"; saura - "lizard") refers to the Triângulo Mineiro , a region in Minas Gereis, from which the fossils come. The second part of the art name, pricei , honors Llewellyn Ivor Price, an important paleontologist and discoverer of the skeletons.
supporting documents
Main source
- Diogenes de Almeida Campos, Alexander WA Kellner, Reinaldo J. Bertini, Rodrigo M. Santucci: On a titanosaurid (Dinosauria, Sauropoda) vertebral column from the Bauru Group, Late Cretaceous of Brazil. In: Arquivos do Museu Nacional. Rio de Janeiro. Vol. 63, No. 3, 2005, ISSN 0365-4508 , pp. 565-593, online .
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 209, online .
- ↑ Leonardo Salgado , Ismar de Souza Carvalho: Uberabatitan ribeiroi, a new titanosaur from the Marília Formation (Bauru Group, Upper Cretaceous), Minas Gerais, Brazil. In: Palaeontology. Vol. 51, No. 4, 2008, ISSN 0031-0239 , pp. 881-901, doi : 10.1111 / j.1475-4983.2008.00781.x .