Captorhinidae

'' Captorhinids are a clade of small to very large lizard-like animals that date from the Late Carboniferous through the Permian. Their skulls were much stronger than those of their relatives, the protorothyridids, and had teeth that were better able to deal with tough plant material. The postcranial skeleton is similar to those of seymouriamorphs and diadectomorphs; these animals were grouped together with the captorhinids in the order Cotylosauria as the first reptiles in the early 20th century, but are now usually regarded as stem-amniotes no closer to reptiles than to mammals. Captorhinids have broad, robust skulls that are generally triangular in shape when seen in dorsal view. The premaxillae are characteristically downturned. The largest captorhinid, the herbivorous Moradisaurus, could reach an estimated snout-vent length (head and body length) of 2 meters (6.5 feet). Early, smaller forms possessed single rows of teeth, and were likely carnivorous or omnivorous, while the larger, more derived captorhinids belonging to the subfamily Moradisaurinae were herbivorous and developed multiple (up to 11) rows of teeth in the jaws alongside propalinal (back and forth) jaw motion, which created an effective apparatus for grinding and shredding plant matter. Histological and SEM analysis of captorhinid tail vertebrae concluded in a 2018 study that captorhinids were the first amniotes to develop caudal autotomy as a defensive function. In studied specimens a split line is present in certain caudal vertebrae that is similar to those found in modern reptiles that perform caudal autonomy. This behaviour represented significant evolutionary benefit for the animals, allowing for escape and distracting predators, as well as minimizing blood loss at an injury site. Mummified specimens of Captorhinus indicate that captorhinids were covered in epidermal scales, similar to modern reptiles, and they had a cartilaginous sternum and cartilaginous extensions of the cervical ribs and trunk ribs, suggesting that they used the intercostal muscles to breathe similarly to modern lizards as opposed to the buccal breathing utilized by amphibians.'' ==Classification==

Taxonomy The following taxonomy follows Reisz et al., 2011 and Sumida et al., 2010 unless otherwise noted. • Family Captorhinidae • Captorhinoides? • Acrodenta • Baeotherates • Captorhinus • Euconcordia • Labidosauriscus • Opisthodontosaurus • Protocaptorhinus • Reiszorhinus • Rhiodenticulatus • Romeria • Saurorictus • Subfamily Moradisaurinae • Amenoyengi • Balearosaurus • Captorhinikos • Gansurhinus • Gecatogomphius • Indosauriscus • Kahneria • Tramuntanasaurus • Dubious captorhinids • Puercosaurus • Riabininus • Chamasaurus Euconcordia cunninghami is thought to be the basalmost known member of Captorhinidae. A phylogenic study of primitive reptile relationships by Muller & Reisz in 2006 recovered Thuringothyris as a sister taxon of the Captorhinidae. The same results were obtained in later phylogenic analyses. However, more recent fossil finds have shown that Eunotosaurus was either a parareptile or a diapsid, and therefore unrelated to captorhinids. Phylogeny The cladogram below follows the topology from a 2011 analysis by paleontologists Robert R. Reisz, Jun Liu, Jin-Ling Li and Johannes Müller. }}}}}}}}}}}}}}}}|label1=Reptiliomorpha}} Using an updated version of this data matrix, Klembara et al. (2023) recovered comparable results. In contrast, Kelsey M. Jenkins et al. (2025) found a clade containing Captorhinidae and Araeoscelidia as the most basal branch of Sauropsida, supporting the traditional classification of captorhinids as a reptiles, though more basal than traditionally assumed, though Xavier A. Jenkins et al. (2025) instead found captorhinids to be considerably outside Amniota. ==References==