"From 230 to 280 million years ago" . . . . . . . "A new gymnarthrid microsaur from the lower permian of Kansas with review of the tuditanomorph microsaurs : (Amphibia)" . . . . . . "A new gymnarthrid microsaur from the Lower Permian of Kansas with a review of the tuditanomorph microsaurs (Amphibia)" . . . . . . . .