In 2005, Bell and Polcyn put forward cladistic taxonomy, which classified Dallas lizards into black dragon subfamily of black dragon. Although Dallas lizards have many ancestral characteristics, the soles of their feet are primitive, similar to lizards, and their bodies are small, the lizard family itself is a parallel group, so Dallas lizards do not belong to the lizard family. Dallas lizard is a sister taxon of other derivative species (such as Cephalotaxus, Diplodocus and Cephalotaxus).