Sphenodus is an extinct genus of shark. It is placed as a member of the extinct family Orthacodontidae, which is either considered to be a member of the extinct order Synechodontiformes, or the modern shark order Hexanchiformes.
Species classification
29 species have been described, though some of these are likely synonyms, which span from the Early Jurassic (Sinemurian) to Paleocene (Danian). ==References==