 The position of Trigonognathus within the Etmopteridae is uncertain . Morphological and molecular phylogenetic data generally support the subdivision of the Etmopteridae into two clades , one consisting of Etmopterus and Miroscyllium and the other consisting of Centroscyllium and Aculeola . Phylogenetic analyses have variously placed Trigonognathus as closer to one clade or the other or as basal to both , depending on which morphological characters , nuclear DNA markers , and / or mitochondrial DNA markers were used . 
