Marasuchus
Marasuchus | ||||||||||||
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Skeleton of marasuchus |
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Temporal occurrence | ||||||||||||
Ladinium ( Middle Triassic ) | ||||||||||||
242 to 235 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Marasuchus | ||||||||||||
Sereno & Arcucci , 1994 | ||||||||||||
Art | ||||||||||||
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Marasuchus is an extinct genus of archosaurs on the lineage of birds ( Ornithodira ). She lived in the late Central Triassic of South America .
Localities and taxonomic history
The remains of Marasuchus or their only and type species Marasuchus illoensis were discovered in the northwest of Argentina in the province of La Rioja in layers of the Chañares formation. These deposits are dated to the late Middle Triassic ( Ladinian , about 242 to 235 million years ago). Already in 1972 these remains were described by Alfred Romer as " Lagosuchus lilloensis ". In 1994, the paleontologists Paul Sereno and Andrea B. Arcucci re- examined the fossils and proposed the new genus Marasuchus for L. lilloensis due to some anatomical differences to the type species of Lagosuchus ( L. tampayalensis ) .
features
Marasuchus lilloensis was about 30 centimeters long. The animal probably ate meat and could already have moved bipedally, like the dinosaurs later .
When comparing the fossils of L. talampayensis and L. lilloensis , Paul Sereno and Andrea B. Arcucci noticed significant anatomical differences. The proportions of the limbs of L. lilloensis were different from those of other well-preserved Middle Triassic ornithodirs. The asymmetry of the fingers of L. lilloensis was less pronounced and the third toe was the longest. L. lilloensis' feet were more like those of a dinosaur than those of Lagerpeton . In addition, in L. lilloensis there was a clear regionalization of the spine into a cervical spine and an anterior and posterior trunk spine section, in contrast to the trunk spine of Pseudosuchia . These features suggest an animal that had a curved cervical and a more or less horizontal vertebral column and walked nimbly on hind limbs with elongated shins and metatarsals .
Systematics
Marasuchus along with nearly contemporary and very similar from the skeleton Ornithodirengattungen, including lagosuchus in the family Lagosuchidae asked. The Lagosuchids are relatively original ornithodirs, which are closer to the dinosaurs (and thus the birds ) than the pterosaurs . The large group of birds, non-avian dinosaurs, lagosuchids and some other extinct taxa is also known as dinosauromorpha .
swell
Main source
- Paul C. Sereno, Andrea B. Arcucci: Dinosaurian precursors from the Middle Triassic of Argentina: Marasuchus lilloensis gen. Nov. In: Journal of Vertebrate Paleontology. Vol. 14, No. 1, 1994, ISSN 0272-4634 , pp. 53-73, doi : 10.1080 / 02724634.1994.10011538 , JSTOR 4523545 .
Others (as footnotes)
- ^ Alfred Sherwood Romer: The Chañares (Argentina) Triassic reptile fauna. XV. Further remains of the thecodonts Lagerpeton and Lagosuchus. In: Breviora . No. 394, 1972 ( archive.org )
Web links
- Marasuchus. Datasheet in the Paleobiology Database