| Captorhinids Temporal range: Pennsylvanian - Lopingian | |
|---|---|
 | |
| Fossil Captorhinus specimens | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Eureptilia |
| Family: | † Captorhinidae Case, 1911 |
| Type species | |
| † Captorhinus aguti | |
| Genera | |
See text | |
| Synonyms | |
Captorhinidae is an extinct family of tetrapods, typically considered primitive reptiles, known from the late Carboniferous to the Late Permian. They had a cosmopolitan distribution across Pangea.
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, [1] 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 of 2 meters (6.5 feet). [2] 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. [3]
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. [4]
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. [5] The same results were obtained in later phylogenic analyses. [6] [7]
Captorhinidae contains a single subfamily, the Moradisaurinae. Moradisaurinae was named and assigned to the family Captorhinidae by A. D. Ricqlès and P. Taquet in 1982. Moradisaurinae was defined as "all captorhinids more closely related to Moradisaurus than to Captorhinus ". The moradisaurines inhabited what is now China, Morocco, Niger, Russia, Texas and Oklahoma. [6]
Captorhinids were once thought to be the ancestors of turtles. The Middle Permian reptile Eunotosaurus from South Africa was seen as the "missing link" between cotylosaurs and chelonians throughout much of the early 20th century. [8] However, more recent fossil finds have shown that Eunotosaurus was either a parareptile or a diapsid, and therefore unrelated to captorhinids. [9] [10]
The following taxonomy follows Reisz et al., 2011 and Sumida et al., 2010 unless otherwise noted. [6] [7]
The cladogram below follows the topology from a 2011 analysis by paleontologists Robert R. Reisz, Jun Liu, Jin-Ling Li and Johannes Müller. [6]
Simões et al. (2022) recovered captorhinids as stem-amniotes instead, as the sister group to Protorothyris archeri , while the clade including captorhinids and P. archeri was recovered as the sister group to Araeoscelidia. A cladogram from that study is shown below. [17] Using the same data matrix, Klembara et al. (2023) found a similar result. [18]
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibious stem tetrapod ancestors during the Carboniferous period. Those of Amniota are defined as the smallest crown clade containing humans, the Greek tortoise, and the Nile crocodile.
Diapsids are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeoscelidians, appeared about three hundred million years ago during the late Carboniferous period. All diapsids other than the most primitive ones in the clade Araeoscelidia are often placed into the clade Neodiapsida. The diapsids are extremely diverse, and include birds and all modern reptile groups, including turtles, which were historically thought to lie outside the group. All modern reptiles and birds are placed within the neodiapsid subclade Sauria. Although some diapsids have lost either one hole (lizards), or both holes, or have a heavily restructured skull, they are still classified as diapsids based on their ancestry. At least 17,084 species of diapsid animals are extant: 9,159 birds, and 7,925 snakes, lizards, tuatara, turtles, and crocodiles.
Eureptilia is one of the two major subgroups of the clade Sauropsida, the other one being Parareptilia. Eureptilia includes Diapsida, as well as a number of primitive Permo-Carboniferous forms previously classified under Anapsida, in the old order "Cotylosauria".
Reptiliomorpha is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was defined by Michel Laurin (2001) and Vallin and Laurin (2004) as the largest clade that includes Homo sapiens, but not Ascaphus truei. Laurin and Reisz (2020) defined Pan-Amniota as the largest total clade containing Homo sapiens, but not Pipa pipa, Caecilia tentaculata, and Siren lacertina.
Diadectomorpha is a clade of large tetrapods that lived in Euramerica during the Carboniferous and Early Permian periods and in Asia during Late Permian (Wuchiapingian), They have typically been classified as advanced reptiliomorphs positioned close to, but outside of the clade Amniota, though some recent research has recovered them as the sister group to the traditional Synapsida within Amniota, based on inner ear anatomy and cladistic analyses. They include both large carnivorous and even larger herbivorous forms, some semi-aquatic and others fully terrestrial. The diadectomorphs seem to have originated during late Mississippian times, although they only became common after the Carboniferous rainforest collapse and flourished during the Late Pennsylvanian and Early Permian periods.
Protorothyrididae is an extinct family of small, lizard-like reptiles belonging to Eureptilia. Their skulls did not have fenestrae, like the more derived diapsids. Protorothyridids lived from the Late Carboniferous to Early Permian periods, in what is now North America. Many genera of primitive reptiles were thought to be protorothyridids. Brouffia, Coelostegus, Paleothyris and Hylonomus, for example, were found to be more basal eureptiles in Muller and Reisz (2006), making the family as historically defined paraphyletic, though three genera, Protorothyris, Anthracodromeus, and Cephalerpeton, were recovered as a monophyletic group. Anthracodromeus, Paleothyris, and Protorothyris were recovered as a monophyletic group in Ford and Benson (2020), who recovered them as more derived than captorhinids and Hylonomus, but less so than araeoscelidians. Anthracodromeus is the earliest known reptile to display adaptations to climbing. The majority of phylogenetic studies recover protorothyridids as basal members of Eureptilia; however, Simões et al. (2022) recover them as stem-amniotes instead.
Seymouria is an extinct genus of seymouriamorph from the Early Permian of North America and Europe. Although they were amphibians, Seymouria were well-adapted to life on land, with many reptilian features—so many, in fact, that Seymouria was first thought to be a primitive reptile. It is primarily known from two species, Seymouria baylorensis and Seymouria sanjuanensis. The type species, S. baylorensis, is more robust and specialized, though its fossils have only been found in Texas. On the other hand, S. sanjuanensis is more abundant and widespread. This smaller species is known from multiple well-preserved fossils, including a block of six skeletons found in the Cutler Formation of New Mexico, and a pair of fully grown skeletons from the Tambach Formation of Germany, which were fossilized lying next to each other.
Varanopidae is an extinct family of amniotes known from the Late Carboniferous to Middle Permian that resembled monitor lizards and may have filled a similar niche. Typically, they are considered to be relatively basal synapsids, although some studies from the late 2010s recovered them being taxonomically closer to diapsid reptiles, recent studies from the early 2020s support their traditional placement as synapsids on the basis of high degree of bone labyrinth ossification, maxillary canal morphology and phylogenetic analyses. A varanopid from the latest Middle Permian Pristerognathus Assemblage Zone is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids.
Parareptilia ("near-reptiles") is an extinct subclass or clade of basal sauropsids/reptiles, typically considered the sister taxon to Eureptilia. Parareptiles first arose near the end of the Carboniferous period and achieved their highest diversity during the Permian period. Several ecological innovations were first accomplished by parareptiles among reptiles. These include the first reptiles to return to marine ecosystems (mesosaurs), the first bipedal reptiles, the first reptiles with advanced hearing systems, and the first large herbivorous reptiles. The only parareptiles to survive into the Triassic period were the procolophonoids, a group of small generalists, omnivores, and herbivores. The largest family of procolophonoids, the procolophonids, rediversified in the Triassic, but subsequently declined and became extinct by the end of the period.
Araeoscelidia or Araeoscelida is a clade of extinct amniotes superficially resembling lizards, extending from the Late Carboniferous to the Early Permian. The group contains the genera Araeoscelis, Petrolacosaurus, the possibly aquatic Spinoaequalis, and less well-known genera such as Kadaliosaurus and Zarcasaurus. This clade is usually considered to be the sister group to all later diapsids.
Captorhinus is an extinct genus of captorhinid reptiles that lived during the Permian period. Its remains are known from North America and possibly South America.
Labidosaurikos is a genus of extinct captorhinid tetrapods that lived around 279 to 272 million years ago during Kungurian age of the lower Permian. The American paleontologist John Willis Stovall first described Labidosaurikos in 1950, naming it "Labidosaurus like" for the striking similarity of the holotype skull of his specimen to the cranial anatomy of another captorhinid Labidosaurus hamatus.
Acleistorhinidae is an extinct family of Late Carboniferous and Early Permian-aged parareptiles. It is defined as a node based clade including the last common ancestor of Acleistorhinus pteroticus and Colobomycter pholeter and all its descendants. Acleistorhinids are most diverse from the Richards Spur locality of the Early Permian of Oklahoma. Richards Spur acleistorhinids include Acleistorhinus, Colobomycter, Delorhynchus, Feeserpeton and Klastomycter. Other taxa include Carbonodraco from the Late Carboniferous of Ohio and Karutia from the Early Permian of Brazil. Acleistorhinidae is commonly considered a subgroup of lanthanosuchoids, related to taxa such as Chalcosaurus, Lanthaniscus and Lanthanosuchus. However, a re-examination of parareptile phylogeny conducted by Cisneros et al. (2021) argued that lanthanosuchids were not closely related to acleistorhinids. The phylogenetic analysis conducted by these authors recovered acleistorhinids as the sister group of the clade Procolophonia, while lanthanosuchids were recovered within the procolophonian subgroup Pareiasauromorpha.
Gansurhinus is an extinct genus of moradisaurine captorhinid known from the Middle Permian Qingtoushan Formation of the Qilian Mountains and the Late Permian Naobaogou Formation in the Daqing Mountains of China. It was first named by Robert R. Reisz, Jun Liu, Jin-Ling Li and Johannes Müller in 2011 and the type species is Gansurhinus qingtoushanensis. A second species, Gansurhinus naobaogouensis, was described in 2023 based on a relatively complete skeleton of an immature individual.
Coelostegus is an extinct genus of Late Carboniferous basal reptile known from Plzeň of Czech Republic. It is known from the holotype ČGH 3027, a partial skeleton of an immature individual. It was collected in the Nýřany site from the Nýřany Member of the Kladno Formation. It was first named by Robert L. Carroll and Donald Baird in 1972 and the type species is Coelostegus prothales. The most recent phylogenic study of primitive reptile relationships found Coelostegus to be the basalmost known eureptile.
Euconcordia is an extinct genus of Late Carboniferous captorhinid known from Greenwood County, Kansas of the United States.
Thuringothyris is an extinct genus of Early Permian eureptiles known from the Thuringian Forest in central Germany.
The Waggoner Ranch Formation is a geologic formation in northern Texas. It preserves fossils dating back to the Artinskian to Kungurian stages of the Permian period.
Pantestudines or Pan-Testudines is the proposed group of all reptiles more closely related to turtles than to any other living animal. It includes both modern turtles and all of their extinct relatives. Pantestudines with a complete shell are placed in the clade Testudinata.
Richards Spur is a Permian fossil locality located at the Dolese Brothers Limestone Quarry north of Lawton, Oklahoma. The locality preserves clay and mudstone fissure fills of a karst system eroded out of Ordovician limestone and dolomite, with the infilling dating to the Artinskian stage of the early Permian (Cisuralian), around 289 to 286 million years ago. Fossils of terrestrial animals are abundant and well-preserved, representing one of the most diverse Paleozoic tetrapod communities known. A common historical name for the site is Fort Sill, in reference to the nearby military base. Fossils were first reported at the quarry by workers in 1932, spurring a wave of collecting by local and international geologists. Early taxa of interest included the abundant reptile Captorhinus and microsaurs such as Cardiocephalus and Euryodus. Later notable discoveries include Doleserpeton, the most diverse assortment of parareptiles in the Early Permian, and the rare early diapsid Orovenator.
| ||||||||||||||||||||||
| ||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
