Placodus, a primitive placodont


Placodont means 'plate-like teeth'.

Placodonts were heavy-bodied reptiles that lived during the Triassic Period (245-200 million years ago). They had short, stout bodies with limbs only moderately specialised as paddles.

Placodonts were not adapted for swimming in the open ocean, and were restricted to the shallow coastal waters of the Tethys Sea.

Placodonts had large, flattened teeth, which were adapted for crushing large molluscs.

Placodonts were relatively small, ranging from 1-3m long.

Advanced placodonts (e.g. Placochelys and Henodus) had specialised dermal armour, superficially like that of a turtle but made of many small plates rather than a few large ones.

Placodonts, like nothosaurs and plesiosaurs, probably laid eggs on land.

The affinities of placodonts are not known, and they became extinct at the end of the Triassic Period, leaving no descendents.


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Author: Rachel Jennings
Last updated: 22/11/2005
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