 In 1970 Romer classified "Macrocnemus" as a lepidosaur related to modern lizards and tuataras, but in 1988 Carroll reclassified it as a member of Protorosauria.Other "protorosaurs" include "Protorosaurus" and "Tanystropheus".Protorosaurs may not form a valid monophyletic clade according to some studies, which place tanystropheids as more derived archosauromorphs than other "protorosaurs".