Placodont
Skull of Placochelys
- Europe
- North America
- Southwest Asia
- North Africa
Placodontier or plaster tooth lizard ( Placodontia ) were a group of reptiles meeresbewohnende the Triassic. They lived in the Tethys and its marginal seas in shallow, coastal regions.
They owe their name to their teeth, with which they could bite through the hard shells of their food (mussels, snails, brachiopods ). The person sitting in the palate teeth had become too large tooth plates, while sitting at the edge of the jaw teeth were conical and blunt. Placodontier were rarely more than two feet long.
The more primitive forms as Placodus still had a partly movable hull, a longer tail and moved well as today's crocodiles by Schlängelschwimmen continued. Your front teeth were spatulate and served to hard-shelled, often sessile animals break loose from the ground. The skull was not as strong as in the ossified Cyamodontoidea, the sutures are still visible. Front and hind legs show only a weak adaptation to life in the sea.
The Placodontier, which are summarized in the taxon Cyamodontoidea were heavily armored to protect against their natural enemies. The tank resembles externally the turtle and is composed of many polygonal bones. Also, the skull is heavily ossified.
Given the lack of possible movements of the trunk and shorter tail them a Schlängelschwimmen was no longer possible. Probably they moved similar to today's sea turtles continued by rowing movements of the fin-like legs. The most extensive armor this group had Henodus, the closed and the upper temporal window has lost the most teeth and replaced by a horned beak. The end of the Triassic the Placodontier did not survive.
System
- Placodontia Saurosphargis
- Paraplacodus
- Placodus
- Cyamodontoidea Henodus
- Cyamodus
- Protenodontosaurus
- Placochelys
- Psephoderma