Rieppel and deBraga conducted a detailed computer analysis of reptiles which revealed that turtles share more characteristics with diapsids
-- modern-day reptiles -- than with anapsids, the more primitive reptile clade to which they long have been assigned.
(2004): The relationships among diapsid reptiles and the influence of taxon selection.
(1996): The diapsid reptile Pachystropheus rhaeticus, a probable choristodere from the Rhaetian of Europe.
Choristoderes presumably evolved from small terrestrial-amphibious Permian diapsids within the northern part of Pangea.
Living reptiles and birds have two holes in the sides of their skulls and are termed diapsids
. The new evidence, however, suggests that crocodiles are closer to turtles than they are to lizards, snakes, and birds--meaning that turtles sit smack in the middle of the reptile tree, rather than off to the side.
Paleontologists label these animals diapsids. Turtles lack any such holes and so are the only living anapsids, a group that includes fossils of the most primitive vertebrates capable of living entirely on land.
Turtles fell squarely within the modern diapsids rather than in their expected position on a branch outside the group, the scientists report in the Nov.