Diadectes
| Diadectes | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Live reconstruction of Diadectes |
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| Temporal occurrence | ||||||||||||
| Unterperm | ||||||||||||
| 290 to 272.5 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Diadectes | ||||||||||||
| Cope , 1878 | ||||||||||||
Diadectes was one of the largest sub-Permian land vertebrates and, along with Edaphosaurus, the largest herbivore of its time. Fossils of the genus have been found in Oklahoma , Utah , Texas, and Germany .
features
Diadectes was three meters long and had a stocky body, massive shoulder and pelvic girdles , short, strong legs, and strong vertebrae and ribs. Overall, his physique resembles that of primitive amniotes . The massive head is highly specialized, including a partially developed secondary palate formed by the palatal bone and an ear slit that is not formed by the scaly bone as in amphibians , but, as in advanced amniotes, by the square bone . The roof of the skull is thick and made of spongy bones. The lower jaw is very high. On the front edge of the upper and lower jaw there are eight short, pin-shaped teeth that were suitable for tearing off parts of plants. On the lateral edges of the jaw there were blunt, laterally widened molars.
Systematics
Diadectes was originally assigned, together with the anthracosaurs and primitive reptiles, to the trunk reptiles (Cotylosauria), a group that is now considered paraphyletic . Later he was considered together with Seymouria as the amphibian closest to the reptiles .
Diadectes is the type genus of the Diadectomorpha of a group of original land vertebrates, to which three other heavily built herbivores also include the carnivorous Limnoscelidae . The Diadectomorpha are now considered a sister group of the amniotes and are placed with them in the taxon Reptiliomorpha , which is the sister group of the amphibians. However, some scientists believe that the Diadectomorpha are the sister group of the synapsids , a taxon that also includes mammals . The Diadectomorpha would be real amniotes. The reason for this assumption is, among other things, a close examination of the occipital region of Diadectes .
literature
- Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme-Verlag, Stuttgart, 1993, ISBN 3-13-774401-6 .
- Michael J. Benton : Paleontology of the vertebrates. 2007, ISBN 3-89937-072-4 .
Individual evidence
- ^ David S. Berman: Origin and Early Evolution of the Amniote Occiput . Journal of Paleontology, vol. 74, no. 5 (Sep., 2000), pp. 938-956 abstract .
Web links
- The Paleobiology Database Diadectes