REPTILE PHYLOGENY AND THE INTERRELATIONSHIPS OF TURTLES

A comprehensive analysis of amniote interrelationships is presented in an attempt to lest turtle interrelationships. The results refute earl ier hypotheses that turtles are related to parareptiles, i.e. to proco lophonids or pareiasaurs. Instead, turtles are shown to be the sister- group of Sauropterygia, the two clades being nested within Sauria as s ister-group of Lepidosauriformes. This scenario is also supported by s everal developmental and soft tissue characters which are shown to be congruent with the current phylogeny. The analysis strongly supports a monophyletic Parareptilia, sister-group of a monophyletic Eureptilia. The Diapsida, however, is paraphyletic unless it includes turtles and sauropterygians. Additionally, the position of turtles within Diapsid a has major implications for the evolutionary history and/or significa nce of many characters, i.e. temporal fenestration. (C) 1997 The Linne an Society of London.