Definition of placodont in English:



  • A marine shellfish-eating reptile of the Triassic period, having short flat grinding palatal teeth and sometimes a turtle-like shell.

    Suborder Placodontia, superorder Sauropterygia: several families and genera, including Placodus

    • ‘The placodont palate bears a rather striking resemblance to the turtle palate except that both the palatines and the maxillae bear huge crushing teeth.’
    • ‘Specifically, it seems quite possible that the choristoderes were originally shellfish-eaters like placodonts and only secondarily became long-snouted fish eaters.’
    • ‘This change is so dramatic that with the exception of a single genus of placodont, all Rhaetian marine reptiles are of the classic ‘Liassic’ (early Jurassic) type.’
    • ‘Ichthyosaurs and sauropterygians (plesiosaurs, placodonts, and nothosaurs) were marine reptiles restricted to the Mesozoic.’
    • ‘It had been suggested some time ago that turtles are closely related to the turtle-like placodonts.’


Late 19th century: from Greek plax, plak- ‘flat plate’ + odous, odont- ‘tooth’.