It is notable for being the earliest known anapsid reptile yet discovered. Classically, turtles were considered to be related to the primitive anapsid reptiles. Most of the earlier anapsid/synapsid megafauna disappeared, being replaced by the archosauromorph diapsids. The smooth softshell turtle has an anapsid skull. The anapsid skull lacks openings behind the orbits. At first, the depressions brought doubts to whether it was anapsid. In 1956, Friedrich von Huene included both amphibians and anapsid reptiles in the Reptiliomorpha. Captorhinidae was transferred to Eureptilia, and Parareptilia included both early anapsid reptiles and turtles. This type of skull roof without any above openings behind the eyes is called "anapsid". "Limnoscelis" had an anapsid skull fenestration pattern, lacking temporal fenestrae.