Psammodontidae is an extinct family of holocephalans (sometimes referred to as bradyodonts)[1] known from the Carboniferous and Permian periods.[2] It is the only family of the order Psammodontiformes.[2] The order and family are named for the type genus, Psammodus, and all members are believed to have been durophagous nektobenthic carnivores.[3] The only remains assigned to Psammodontidae are isolated tooth plates.