Lystrosaurus georgi, a dicynodont from the Lower Triassic of Russia

Abstract

ABSTRACT The postcranial skeleton of Lystrosaurus georgi from the lowermost Triassic of the Moscow Basin, Russia, is described for the first time. This species retains contact between the premaxillae and palatine and is characterized by a narrow and elongated ischium, an autapomorphy for this species. Phylogenetic analysis of 27 Permian and Triassic dicynodont taxa using 18 postcranial characters confirms other recent hypotheses, but does not support a close relationship between Cistecephalus and Kingoria. The low homoplasy level among characters of the pelvis and femur, compared with the shoulder girdle and forelimbs, suggests that the former region documents the pattern of anomodont evolution better than the latter. Analysis of character changes revealed that a general evolutionary trend in the dicynodont postcranium relates to acquisition of semisprawling locomotion.