|
Sphenodont
Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a diverse group including a wide array of morphologically distinct forms. 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. Many of the niches occupied by lizards today were held by sphenodontians during the Triassic and Jurassic, although lizard diversity began to overtake sphenodontian diversity in the Cretaceous, and they had disappeared almost entirely by the beginning of the Cenozoic. While the modern tuatara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clevosaurus
''Clevosaurus'' (meaning "Gloucester lizard") is an extinct genus of rhynchocephalian reptile from the Late Triassic and the Early Jurassic periods. Species of ''Clevosaurus'' were widespread across Pangaea, and have been found on all continents except Australia and Antarctica. Five species of ''Clevosaurus'' have been found in ancient fissure fill deposits in south-west England and Wales, alongside other sphenodontians, early mammals and dinosaurs. In regards to its Pangaean distribution, ''C. hadroprodon'' is the oldest record of a sphenodontian from Gondwana, though its affinity to ''Clevosaurus'' has been questioned. History of discovery The first species of ''Clevosaurus'' to be described was ''C. hudsoni'', which was described by William Elgin Swinton in 1939 from a fissure fill deposit in Cromhall Quarry ( Magnesian Conglomerate Formation) in the county of Gloucestershire, England, with the name of the county lending its name to the genus. Description ''Clevosaurus' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthodontia (reptiles)
Opisthodontia is a proposed clade of sphenodontian reptiles, uniting ''Opisthias'' from the Late Jurassic-earliest Cretaceous of Europe and North America with the Elienodontinae, a group of herbivorous sphenodontians known from the Late Triassic to Late Cretaceous. Description Teeth and diet Like other sphenodonts, opisthodonts had acrodont teeth which grew directly from the bone. They had one row of teeth on the lower jaw and two rows on the roof of the mouth. When processing food, their mandibular teeth would have slid between the outer (maxillary) teeth and inner (palatine) teeth. Some opisthodonts, such as '' Sphenotitan'', also had clusters of small teeth on the pterygoid at the center of the mouth roof. Opisthodont teeth were wide, numerous, and tightly-packed for grinding and shredding tough plant matter. Although wide shredding teeth are also known in a few other sphenodontians, such as ''Clevosaurus'' and ''Pelecymala'', the most diverse and long-lasting group of he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sapheosaur
Sapheosaurs are an extinct group of rhynchocephalian reptiles from the Late Jurassic period. "Sapheosaurs" is an informal name for a group of rhynchocephalians closely related to the genus ''Sapheosaurus''. It was first recognized as a group containing multiple genera by Hoffstetter in 1955. The group has sometimes been given a formal taxonomic name as the family Sapheosauridae, although in some analyses this group belongs to the family Sphenodontidae (which also contains the tuatara, the only living rhynchocephalian) and thus cannot be assigned its own family. They were fairly advanced rhynchocephalians which may have had semiaquatic habits. Classification The most well-known members of the group are ''Sapheosaurus'' and ''Kallimodon'', and most phylogenetic analyses on rhynchocephalians only study these two genera as representatives of sapheosaurs. Although a few early phylogenies in the 1990s did not find that these two formed a natural clade, the relation between these two i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamarquesaurus
''Lamarquesaurus'' is an extinct genus of sphenodontian from the Late Cretaceous (Campanian) of Patagonia. It is known from a single species, ''Lamarquesaurus cabazai''. This genus and species is represented by MML-PV-42, a well-preserved right maxillary bone (including 10 teeth of varying completeness). This bone was found at the Cerro Tortuga site near Lamarque, Argentina, which preserves fossils from the Cretaceous Allen Formation. The discoverer of the Cerro Tortuga locality, Tito Cabaza, is the namesake of the species. Description The maxilla is in length; including missing portions it would have been about long if complete. The inner surface of the maxilla is deeply concave but the outer surface has several scattered pits as well as deep facets above the third and fifth teeth. These facets are reminiscent of those which sphenodonts possess on the lower jaw due to abrasion from teeth of the upper jaw, but this cannot be the case in ''Lamarquesaurus'''s maxilla. This is be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitakersaurus
''Whitakersaurus'' is a genus of sphenodontid rhynchocephalian reptile dated to be late Triassic in age and is from the Ghost Ranch fossil quarry in New Mexico, USA. It is named after the discoverer of the Ghost Ranch quarry, George O. Whitaker. The fossil was described in 2007. Features The left and right dentary are preserved, along with a fragmentary left maxilla and probable palatal bone, on two blocks of stone. Dentary bones The left dentary is fragmented but still has almost all teeth present, whereas the right dentary is incomplete and has most of the teeth. The left dentary is 11 mm long and has multiple broken teeth or tooth positions. The coronoid process is missing, but there may be a suture present where the dentary was joined to the surangular. A small groove is present on the lingual side of teeth 16-18. The right dentary is only partial, unlike the left dentary where all the fragments are present, but the piece preserved is 9 mm long. The posterior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphydontosaurus
''Diphydontosaurus'' is an extinct genus of rhynchocephalian reptile from the Late Triassic of England and Italy. This small animal was related to the living tuatara (''Sphenodon''). It may have grown to a length of . It is more derived than ''Gephyrosaurus'', yet more primitive than ''Planocephalosaurus'', and shares traits with both of them. Description ''Diphydontosaurus'' was a small sphenodontian, measuring up to long. It had long, sharp claws to help it catch its prey, and peg-like piercing teeth to help it eat insects. These features are shared with the other primitive rhynchocephalians ''Gephyrosaurus'' and ''Planocephalosaurus''. Classification ''Diphydontosaurus'' is known from many mostly complete specimens, which means that its classification as a rhynchocephalian is quite certain. In an analysis by Oliver Rahut and colleagues in 2012, it was found that ''Diphydontosaurus'' is the second most basal rhynchocephalian, after ''Gephyrosaurus'', and the most primitive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenodon Punctatus
Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and means "peaks on the back". The single extant species of tuatara is the only surviving member of its order. Rhynchocephalians originated during the Triassic (~250 million years ago), reached worldwide distribution and peak diversity during the Jurassic and, with the exception of tuatara, were extinct by 60 million years ago. Their closest living relatives are squamates (lizards and snakes). For this reason, tuatara are of interest in the study of the evolution of lizards and snakes, and for the reconstruction of the appearance and habits of the earliest diapsids, a group of amniote tetrapods that also includes dinosaurs (including birds) and crocodilians. Tuatara are greenish brown and grey, and measure up to from head to tail-tip and wei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenodontidae
Sphenodontidae is a family within the reptile group Rhynchocephalia, comprising taxa most closely related to the living tuatara of the genus ''Sphenodon''. Historically the taxa included within Sphenodontidae have varied greatly between analyses, and the group has lacked a formal definition. '' Cynosphenodon'' from the Early Jurassic of Mexico has consistently been recovered as a close relative of the tuatara in most analyses, with the clade containing the two often called Sphenodontinae. The herbivorous Eilenodontinae, otherwise considered part of Opisthodontia, is also sometimes considered part of this family as the sister group to Sphenodontinae. Sphenodontines first appeared during the Early Jurassic, and are characterised by a complete lower temporal bar caused by the fusion of the quadrate/quadratojugal and the jugal 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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micromenodon
''Micromenodon'' is an extinct genus of sphenodontian from the Late Triassic Doswell Formation of Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar .... It contains a single species, ''Micromenodon pitti.'' References {{Sphenodontia Sphenodontia Triassic species Triassic reptiles Triassic reptiles of North America Fossil taxa described in 2021 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurosauridae
Pleurosauridae is an extinct family of sphenodontian reptiles, known from the Jurassic of Europe. Members of the family had long-snake like bodies with reduced limbs that were adapted for aquatic life in marine environments. It contains two genera, ''Palaeopleurosaurus,'' which is known from the Early Jurassic (Toarcian) Posidonia Shale of Germany, as well as ''Pleurosaurus'' from the Late Jurassic of Germany and France. ''Paleopleurosaurus'' is more primitive than the later ''Pleurosaurus'', with a skull similar to those of other sphenodontians, while that of ''Pleurosaurus'' is highly modified relative to other sphendontians. They likely swam via anguilliform locomotion.Dupret, V. (2004). The pleurosaurs: anatomy and phylogeny. ''Revue de Paléobiologie'', 9: 61-8/ref> ''Vadasaurus'' and ''Derasmosaurus ''Derasmosaurus'' is an extinct species of rhynchocephalian known from the Pietraroja Plattenkalk of Italy. It was originally considered to be a specimen of ''Lacerta brev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pamizinsaurus
''Pamizinisaurus'' is a genus of sphenodontian reptile known from Lower Cretaceous (Albian) Tlayúa Formation of Mexico. A crushed skeleton of a juvenile reptile was found in Tlayua Quarry, in central Mexico. It was named ''Pamizinsaurus tlayuaensis'' by Reynoso in 1997, after the name of the quarry of which it was found. Its skull length is . The fossil was covered in small round osteoderms that could have protected it from predators. Relatives Reynoso (1997) argued that ''Pamizinsaurus'' was a genus of the subfamily Sphenodontinae; grouping it with the modern ''Sphenodon'' (better known as the ''Tuatara''), '' Zapatadon'', '' Cynosphenodon'', ''Homoeosaurus'', ''Sapheosaurus'', and ''Ankylosphenodon ''Ankylosphenodon'' is an extinct species of sphenodontian known from Tepexi de Rodriguez, Mexico. It is known from Early Cretaceous sedimentary deposits from the Tlayua formation. Lifestyle ''Ankylosphenodon'' is thought to have been an aqu ...''. References External ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theretairus
''Theretairus'' is a Late Jurassic genus of sphenodont reptile from the Morrison Formation of western North America,Foster, J. (2007). "Table 2.1: Fossil Vertebrates of the Morrison Formation." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 58-59. present in stratigraphic zones 5 and 6.Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327-329. History and naming The holotype consists of a right mandible and several in-socket teeth from Quarry 9 at Como Bluff, Wyoming where it was excavated by paleontologist William Harlow Reed, who then was working for Othniel Charles Marsh, and it was deposited at the Yale Peabody Museum under YPM VP 13764. The locality comes from strata of the Brushy Basin Member of the Morrison Formation, which also bears other sphenodontians ''Opisthias'' and ''Eilenodon.''Rasmussen, T. E.; Callison, George (198 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_601758.jpg "Click for more on -> Sphenodont")
