Produced by the Population Genetics and Evolution class, Furman University

The Triassic: Placodonts
Placodonts (“tablet teeth”) were marine reptiles that are believed to be descended from the Sauropterygia, a group that included Plesiosaurs (Naish 2000). First discovered in 1830, their range was previously thought to be limited to Europe, the Middle East, and North Africa before researchers found a specimen in Asia (Chun 2002). Placodonts were about 1 to 2 meters in length and had armor plating, dense bones, and strong, flat teeth. They likely fed on mollusks and other bivalves, using their large, flat teeth to crush the shells of their prey before eating the soft parts. Although they were amphibious, their relatively dense bodies, short limbs, and lack of flippers or propulsive tail probably limited them to shallow areas. Placodonts were almost certainly clumsy on land, given their awkward suite of morphological traits. However, they did occasionally venture onto land to rest, breed, and avoid predators (Naish 2000). They went extinct near the end of the Triassic, most likely due to a decline in the availability of shelled prey (Buffetaut 2008). Placodonts have no known extant descendents (Naish 2000).

Page by Robert Mazgaj
Placodont. Photo By: Dan Varner

Buffetaut E. and Matevz N. 2008. A cyamodontoid placodont (Reptilia: Sauropterygia) from the Triassic of Slovenia. Paleontology 51: 1301–1306.

Chun L. and Rieppel O. 2002. A new cyamodontoid placodont from Triassic of Guizhou, China. Chinese Science Bulletin 47: 403-407.

Naish D. 2000. Placodonts: the bizarre ‘walrus turtles’ of the Triassic. Accessed Mar. 23 2010.