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.
Rhynchocephalia is an order of lizard-like reptiles that includes only one living species, the tuatara of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a speciose group with high morphological and ecological diversity. The oldest record of the group is dated to the Middle Triassic around 238 to 240 million years ago, and they had achieved a worldwide distribution by the Early Jurassic. Most rhynchocephalians belong to the group Sphenodontia ('wedge-teeth'). Their closest living relatives are lizards and snakes in the order Squamata, with the two orders being grouped together in the superorder Lepidosauria.
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.
Lepidosauromorpha is a group of reptiles comprising all diapsids closer to lizards than to archosaurs. The only living sub-group is the Lepidosauria, which contains two subdivisions, Squamata, which contains lizards and snakes, and Rhynchocephalia, the only extant species of which is the tuatara.
Kuehneosaurus is an extinct genus of Late Triassic kuehneosaurid reptile known from the Late Triassic of the Penarth Group of southwest England and the Steinmergel Group of Luxembourg. Temperature at this stage and region would have ranged from 28 to 35 °C. It was named by P. L. Robinson in 1962 in honour of paleontologist Walther Kühn, and the type and only species is Kuehneosaurus latus. Measuring 72 centimetres long, it had "wings" formed from ribs which jutted out from its body by as much as 14.3 cm, connected by a membrane which allowed it to slow its descent when jumping from trees. It is a member of a family of extinct gliding reptiles, the Kuehneosauridae, within a larger living group the Lepidosauromorpha, which contain modern lizards and tuatara.
Elachistosuchus is an extinct genus of neodiapsid reptile, most likely basal archosauromorph, known from the Late Triassic Arnstadt Formation of Saxony-Anhalt, central Germany. It contains a single species, Elachistosuchus huenei, known from a single individual E. huenei, originally considered a pseudosuchian archosaur and then a rhynchocephalian lepidosaur, was largely ignored in the scientific literature, as its small size and fragility did not permit further mechanical preparation and examination. More recently however, a non-invasive μCT scanning was performed to resolve its placement within Reptilia, and found it to represent a more basal reptile, potentially closely related to several early archosauromorph clades.
Tasmaniosaurus is an extinct genus of archosauromorph reptile known from the Knocklofty Formation of West Hobart, Tasmania, Australia. The type species is T. triassicus. This genus is notable not only due to being one of the most complete Australian Triassic reptiles known, but also due to being a very close relative of Archosauriformes. Once believed to be a proterosuchid, this taxon is now believed to have been intermediate between advanced non-archosauriform archosauromorphs such as Prolacerta, and basal archosauriforms such as Proterosuchus. Features traditionally used to define Archosauria and later Archosauriformes, such as the presence of an antorbital fenestra and serrated teeth, are now known to have evolved prior to those groups due to their presence in Tasmaniosaurus.
Kuehneosauridae is an extinct family of small, lizard-like gliding diapsids known from the Triassic period of Europe and North America.
Gephyrosaurus is an extinct genus of lepidosaurian reptile known from the Late Triassic to Early Jurassic of the United Kingdom. It is generally considered to be one of the most primitive members of the clade Rhynchocephalia.
Sophineta is an extinct genus of basal lepidosauromorph reptile known from the Early Triassic of Małopolska Province, southern Poland. It contains a single species, Sophineta cracoviensis.
Jesairosaurus is an extinct genus of early archosauromorph reptile known from the Illizi Province of Algeria. It is known from a single species, Jesairosaurus lehmani. Although a potential relative of the long-necked tanystropheids, this lightly-built reptile could instead be characterized by its relatively short neck as well as various skull features.
Marmoretta is an extinct genus of small lepidosauromorph reptile known from the Middle Jurassic (Bathonian) of Britain, as well as the Late Jurassic of Portugal. It contains a single species, Marmoretta oxoniensis.
Prolacertoides is an extinct genus of archosauromorph reptile from the Early Triassic of China, the type species being Prolacertoides jimusarensis. Prolacertoides means 'like Prolacerta', in reference to Prolacerta, another genus of archosauromorph which Prolacertoides was once believed to have been closely related to. Prolacertoides is known from a single partial skull, IVPP V3233, which was discovered in Xinjiang in northwestern China. The locality of its discovery belongs to the Cangfanggou Group of the Jiucaiyuan Formation, which is dated to the Induan age of the very early Triassic.
Fuyuansaurus is an extinct genus of "protorosaur" reptiles known from the Middle Triassic Zhuganpo Formation of southern China. Fuyuansaurus was first named by Nicholas C. Fraser, Olivier Rieppel and Li Chun in 2013 and the type species is Fuyuansaurus acutirostris.
Pleurodontagama is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia. The type species, Pleurodontagama aenigmatodes, was named in 1984 on the basis of a mostly complete skull and isolated lower jaw from a fossil locality called Khermeen Tsav. It has a wide skull with a flat snout, large eye sockets, and small bumps on the surfaces of the bones. Pleurodontagama was initially classified in the family Priscagamidae, which is usually grouped in a large clade of iguanians called Acrodonta, members of which are characterized by an "acrodont" dentition in which the teeth grow from the margins of the jaws. However, Pleurodontagama is unusual in that it has a sub-pleurodont dentition, meaning that some of its teeth grow from the inner surfaces of the jaw. There is also evidence to suggest that its teeth may have been continuously replaced throughout life, as opposed to the permanent teeth of acrodontans. Pleurodontagama may have been a transitional form between the derived acrodont type and the pleurodont type inferred for the ancestors of Acrodonta.
Kadimakara is an extinct genus of early archosauromorph reptile from the Arcadia Formation of Queensland, Australia. It was seemingly a very close relative of Prolacerta, a carnivorous reptile which possessed a moderately long neck. The generic name Kadimakara references prehistoric creatures from Aboriginal myths which may have been inspired by ice-age megafauna. The specific name K. australiensis relates to the fact that it was found in Australia. Prolacerta and Kadimakara were closely related to the Archosauriformes, a successful group which includes archosaurs such as crocodilians, pterosaurs, and dinosaurs.
Colobops is a genus of reptile from the Late Triassic of Connecticut. Only known from a tiny skull, this reptile has been interpreted to possess skull attachments for very strong jaw muscles. This may have given it a very strong bite, despite its small size. However, under some interpretations of the CT scan data, Colobops's bite force may not have been unusual compared to other reptiles. The generic name, Colobops, is a combination of κολοβός, meaning shortened, and ὤψ, meaning face. This translation, "shortened face", refers to its short and triangular skull. Colobops is known from a single species, Colobops noviportensis. The specific name, noviportensis, is a latinization of New Haven, the name of both the geological setting of its discovery as well as a nearby large city. The phylogenetic relations of Colobops are controversial. Its skull shares many features with those of the group Rhynchosauria, herbivorous archosauromorphs distantly related to crocodilians and dinosaurs. However, many of these features also resemble the skulls of the group Rhynchocephalia, an ancient order of reptiles including the modern tuatara, Sphenodon. Although rhynchosaurs and rhynchocephalians are not closely related and have many differences in the skeleton as a whole, their skulls are remarkably similar. As Colobops is only known from a skull, it is not certain which one of these groups it belonged to. Pritchard et al. (2018) interpreted it as a basal rhynchosaur, while Scheyer et al. (2020) reinterpreted it as a rhynchocephalian.
Polymorphodon is an extinct genus of archosauriform reptile from the Middle Triassic of Germany. The only known species is Polymorphodon adorfi, discovered in Lower Keuper deposits at a quarry in Eschenau, Germany. Polymorphodon is notable for its heterodont dentition, with long and conical premaxillary teeth followed by thin maxillary teeth with large serrations. Maxillary teeth near the back of the mouth are short and leaf-shaped, similar to some living and extinct reptiles with a herbivorous or omnivorous diet. This may suggest that Polymorphodon had some reliance on plants in its diet, a rarity among basal archosauriforms, most of which are carnivores.
Taytalura is an extinct genus of lepidosauromorph reptile from the Late Triassic of Argentina. It contains a single species, Taytalura alcoberi, which is based on a well-preserved skull from the fossiliferous Ischigualasto Formation. As a lepidosauromorph, Taytalura is a distant relative of modern lepidosaurs such as sphenodontians and squamates. Taytalura did not belong to any group of modern lepidosaurs, since it bears unique features, such as unfused bones in the skull roof and teeth which all sit loosely in a deep groove without sockets. Regardless, Micro-CT scanning reveals features of the skull previously only seen in rhynchocephalians. This suggests that the ancestral condition of the skull in lepidosaurs was more similar to sphenodonts than to squamates.
Yelaphomte is an extinct genus of non-pterodactyloid pterosaur from the late Norian–early Rhaetian-aged Quebrada del Barro Formation of Argentina. It lived in the Late Triassic period, and is one of the only known definitive Triassic pterosaurs from the southern hemisphere. It was a small and crested pterosaur, although its small size may be due to immaturity. It is also one of the few known continental Triassic pterosaurs, indicating that the absence of early pterosaurs in both the southern hemisphere and terrestrial environments is likely a sampling bias, and not a true absence.
