Article: The diapsid reptile, Pachystropheus rhaeticus, a probable choristodere from the Rhaetian of Europe

The enigmatic Upper Triassic reptile, Pachystropheus rhaeticus, displays characters suggestive of choristoderan affinity and, as such, is potentially the oldest known choristoderan reptile. Examination of the blown skeletal elements indicates that the choristoderan lineage remained morphologically conservative throughout its recorded history. The occurrence of Pachystropheus fossils in marginal marine bone beds, however, may reflect a previously unrecognized shift of habitat for the Choristodera, from the paralic environments occupied by early representatives, to the more typical freshwater, often fluvial, deposits containing later forms.