Captorhinida

Captorhinida is an extinct order of reptiles that lived during the Permian and Triassic periods. These reptiles are notable for being among the earliest fully terrestrial vertebrates. They are considered to be primitive members of the diapsid lineage, though their exact placement within the reptilian evolutionary tree has been debated. Captorhinids were characterized by their small to medium size, with most species ranging from a few inches to about three feet in length.

A defining feature of many captorhinids is the presence of multiple rows of teeth on the palate, a trait known as pleurodonty. This dental adaptation suggests a diet that likely included insects, small invertebrates, and possibly plants. Their skulls were generally robust, and they possessed a solid, anapsid-like skull roof, meaning they lacked temporal fenestrae (openings) behind the orbits. However, this anapsid condition is now understood to be a primitive feature inherited from their ancestors, rather than a defining characteristic of the group within the context of diapsid evolution.

Fossil evidence of captorhinids has been found in North America and Europe. They were a diverse group, with various genera and species exhibiting adaptations to different Permian environments. Their success in colonizing terrestrial habitats marks a significant step in reptilian evolution. The order eventually went extinct by the end of the Triassic period, likely succumbing to competition from more advanced reptile groups that arose during the Mesozoic Era.