In the original description of "Dinocephalosaurus", Li recognized the postorbital region and the elongated cervical centra as being indicative of a close relationship with "Tanystropheus", which led him to assign it to the Tanystropheidae. However, Rieppel and colleagues subsequently noted characteristics that distinguished "Dinocephalosaurus" from derived protorosaurs such as "Tanystropheus", "Macrocnemus", "Langobardisaurus", and "Tanytrachelos"; these include the lack of tapering at the front end of the nasal and an unreduced contribution of the ilium to the acetabulum. This led Rieppel and colleagues to consider "Dinocephalosaurus" as an indeterminate protorosaur, with its neck elongation been convergent upon that of "Tanystropheus". Their phylogenetic tree, based on a dataset derived from the separate analyses of Jalil (1997), David Dilkes (1998), and Michael Benton & Jackie Allen (1997), is reproduced below, at left.