The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side (closest to the tongue) between the angular and surangular. [1] [2]
The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side (closest to the tongue) between the angular and surangular. [1] [2]
The Lepidosauria is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes lizards and snakes. Squamata contains over 9,000 species, making it by far the most species-rich and diverse order of non-avian reptiles in the present day. Rhynchocephalia was a formerly widespread and diverse group of reptiles in the Mesozoic Era. However, it is represented by only one living species: the tuatara, a superficially lizard-like reptile native to New Zealand.
The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids, and early synapsids.
The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species.
Archosauromorpha is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs rather than lepidosaurs. Archosauromorphs first appeared during the late Middle Permian or Late Permian, though they became much more common and diverse during the Triassic period.
Euryapsida is a polyphyletic group of sauropsids that are distinguished by a single temporal fenestra, an opening behind the orbit, under which the post-orbital and squamosal bones articulate. They are different from Synapsida, which also have a single opening behind the orbit, by the placement of the fenestra. In synapsids, this opening is below the articulation of the post-orbital and squamosal bones. It is now commonly believed that euryapsids are in fact diapsids that lost the lower temporal fenestra. Euryapsids are usually considered entirely extinct, although turtles might be part of the sauropterygian clade while other authors disagree. Euryapsida may also be a synonym of Sauropterygia sensu lato.
Toxicofera is a proposed clade of scaled reptiles (squamates) that includes the Serpentes (snakes), Anguimorpha and Iguania. Toxicofera contains about 4,600 species, of extant Squamata. It encompasses all venomous reptile species, as well as numerous related non-venomous species. There is little morphological evidence to support this grouping; however, it has been recovered by all molecular analyses as of 2012.
Petrolacosaurus is an extinct genus of diapsid reptile from the late Carboniferous period. It was a small, 40-centimetre (16 in) long reptile, and one of the earliest known reptile with two temporal fenestrae. This means that it was at the base of Diapsida, the largest and most successful radiation of reptiles that would eventually include all modern reptile groups, as well as dinosaurs and other famous extinct reptiles such as plesiosaurs, ichthyosaurs, and pterosaurs. However, Petrolacosaurus itself was part of Araeoscelida, a short-lived early branch of the diapsid family tree which went extinct in the mid-Permian.
The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone.
Labidosaurus is an extinct genus of captorhinid tetrapods from the Permian period of North America. Fossils have been discovered in Texas.
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.
Procolophon is a genus of lizard-like procolophonid parareptiles that first appeared in the Early Triassic (Induan) of South Africa, Brazil, and Antarctica. It persisted through the Permian–Triassic extinction event, but went extinct in the beginning of the Early Middle Triassic. The type species is P. trigoniceps.
Trilophosaurus is a lizard-like trilophosaurid allokotosaur known from the Late Triassic of North America. It was a herbivore up to 2.5 m long. It had a short, unusually heavily built skull, equipped with massive, broad flattened cheek teeth with sharp shearing surfaces for cutting up tough plant material. Teeth are absent from the premaxilla and front of the lower jaw, which in life were probably equipped with a horny beak.
Thuringothyris is an extinct genus of Early Permian eureptiles known from the Thuringian Forest in central Germany.
Coelodontognathus is an extinct genus of reptile from the Early Triassic of European Russia. It was originally described as a procolophonid parareptile in 1967 but was reclassified as a possible trilophosaurid archosauromorph in 2008. The genus includes two species: the type species C. donensis and C. ricovi. C. donensis is known from the holotype PIN 4173/129 and the referred PIN 4173/130, and C. ricovi is known from the holotype PIN 4173/127 and the referred PIN 4173/128, all of which represent dentaries that are housed at the Paleontological Institute, Russian Academy of Sciences. Another dentary, SGU 104/3105, originally referred to C. donensis was reassigned to its own genus and species Vitalia grata by Ivakhnenko, 1973. The fossils have been found at the Donskaya Luka Locality near the village of Sirotinskaya and the Don River in Ilovlinsky District, Volgograd Oblast, from the Lipovskaya Formation of the Gamskii Horizon. Like Coelodontognathus, Vitalia which is known from the same locality was also first identified as a procolophonid and later reclassified as a trilophosaurid. Coelodontognathus and Vitalia are similar to procolophonids in that they have wide teeth but differs from them in that they have tooth roots set deep into the jaws.
Palatodonta is an extinct genus of neodiapsid reptile known from the early Middle Triassic of the Netherlands. It was initially described in 2013 as a basal placodontiform closely related to a group of marine reptiles called placodonts, characterized by their crushing teeth and shell-like body armor. Under this interpretation, Palatodonta is transitional between placodonts and less specialized reptiles. Like placodonts, it has a row of large teeth on its palate, but while these teeth are thick and blunt in placodonts, Palatodonta has palatal teeth that are thin and pointed. A 2023 study instead classified it as a sauropterygomorph and the sister taxon to Eusaurosphargis. In other words, it is close to, but not within, Sauropterygia.
The Ichthyosauromorpha are an extinct clade of Mesozoic marine reptiles consisting of the Ichthyosauriformes and the Hupehsuchia.
Doniceps is an extinct genus of reptile from the Early Triassic of European Russia known from the type species D. lipovensis. It was solely known from the holotype premaxilla 104/3106 housed at Saratov University, however the specimen is probably lost. It was collected at the Donskaya Luka Locality near the village of Sirotinskaya in Ilovlinsky District, Volgograd Oblast, from the Lipovskaya Formation of the Gamskii Horizon. The generic name refers to the nearby Don River added the Greek suffix for "head", -ceps. The specific name is derived from the name of the type locality Donskaya Luka, also known as Lipovaya Balka. Named by Otschev and Rykov in 1968 as an archosauromorph, Arkhangelskii & Sennikov (2008) classified the taxon as a possible trilophosaurid. Doniceps is thought to be similar to Coelodontognathus and Vitalia, both of which are known exclusively from the same locality and were first identified as procolophonids but later reclassified as trilophosaurids.
Vitalia is an extinct genus of reptile from the Early Triassic of European Russia known from the type species V. grata. It is known from the holotype dentary PIN 4173/126 as well as two additional dentaries PIN 1043/627 and 1043/628, all housed at the Paleontological Institute, Russian Academy of Sciences. The type dentary was originally included in the hypodigm of Coelodontognathus donensis named by the notable Russian vertebrate paleontologist Vitaliy Georgiyevich Ochev in 1967. Ivakhnenko (1973) separated the specimen and gave it its own genus and species name in light of the new material, which he named in honor of Ochev. The dentaries of Vitalia were collected at the Donskaya Luka Locality near the village of Sirotinskaya in Ilovlinsky District, Volgograd Oblast, from the Lipovskaya Formation of the Gamskii Horizon. Like Coelodontognathus, Vitalia was originally described as a procolophonid parareptile in 1973, but Arkhangelskii & Sennikov (2008) reclassified the taxon as a possible trilophosaurid archosauromorph. Vitalia is thought to be similar to the possible trilophosaurids Coelodontognathus and Doniceps, both of which are known exclusively from the same locality. Coelodontognathus and Vitalia are similar to procolophonids in that they have wide teeth but differs from them in that they have tooth roots set deep into the jaws.
Zarcasaurus tanyderus is a species of araeoscelidian tetrapods found in the Cutler Formation of New Mexico. The only elements of the skeleton known from this animal is a partial jaw bone, vertebrae, and broken limb bones.
Rhodotheratus is an extinct genus of captorhinid tetrapods from the Early Permian Hennessey Formation of Oklahoma. The type species is R. parvus.
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