Petromyzontiformes is an order of vertebrates. There are 47 species of Petromyzontiformes, in 10 genera and 3 families. It includes groups like Petromyzontidae, Geotriidae, and Mordaciidae.
Definition: overall repetitive or reflective pattern in the body of one individual of this taxon. eg: bilateral symmetry, rotational symmetry, radial symmetry