Placodont
extinct group of marine reptiles, Triassic period / From Wikipedia, the free encyclopedia
Placodonts were a group of Triassic marine reptiles which had heavy flat teeth. These teeth were used for crushing shellfish.[1] Placodonts are in the Order Sauropterygia, the group that includes Plesiosaurs. Placodonts were mostly between 1 to 2 metres (3 to 7 ft) in length, up to a maximum 3 metres (10 ft) long. They are found in marine sediments of the Middle and Upper Triassic, 235–250 million years ago.[1][2]
Placodont Temporal range: Middle to Upper Triassic 235 to 201 mya | |
---|---|
Placodus, type genus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Superorder: | †Sauropterygia |
Clade: | †Placodontiformes |
Order: | †Placodontia Cope, 1871 |
The first specimen was discovered in 1830, and the group was very widely distributed. Shellfish were common throughout the Mesozoic period, but this group of shellfish-eaters went extinct at the end of the Triassic. They were clearly a victim of some event which disturbed their lifestyle. The end-Triassic had several extinction events which are not well understood.