Younginiformes
Younginiformes | ||||||||||||
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Acerosodontosaurus piveteaui , an aquatic reptile whose fossil remains have been found in Madagascar. |
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Temporal occurrence | ||||||||||||
Wuchiapingium ( Upper Permian ) to Indusian ( Lower Triassic ) | ||||||||||||
259.9 to 251.2 million years | ||||||||||||
Locations | ||||||||||||
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Younginiformes | ||||||||||||
Romer , 1945 |
The Younginiformes , formerly called Eosuchia , are an extinct taxon of diapsid reptiles from the Upper Permian and Lower Triassic . They were medium-sized, lizard-like animals that ate insectivor or carnivorous. Some, such as the genus Acerosodontosaurus and Hovasaurus found in Madagascar and East Africa, lived aquatic. They differed from the terrestrial only by their flattened tail, but had stones in the abdominal cavity, which probably served as ballast.
The taxon is possibly paraphyletic , as the Lepidosauromorpha may have emerged from them .
features
The neck and distal elements of the limbs are much shorter than those of the Araeoscelidia . The animals had a single coracoid that was missing tabulare (a skull bone). The vertebrae had transverse transverse processes and relatively high neural processes. The columella , a bone in the middle ear that converges to the mammalian stapes , was large. A sternum was present, as was the cleithrum , a bone that is no longer present in modern reptiles. The foot and tarsus were primitive.
Genera
literature
- Robert L. Carroll : Paleontology and Evolution of the Vertebrates , Thieme, Stuttgart (1993), ISBN 3-13774-401-6
- Michael J. Benton : Paleontology of the vertebrates. 2007, ISBN 3899370724
- Oskar Kuhn: Handbook of Paläoherpetologie. Part 9, Gustav Fischer Verlag, 1969,
Web links
- Palæos Younginiformes ( Memento from December 21, 2010 in the Internet Archive )