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Pantestudines
Pantestudines or Pan-Testudines is the group of all reptiles more closely related to turtles than to any other living animal. It includes both modern turtles (crown group turtles, also known as Testudines) and all of their extinct relatives (also known as stem-turtles). Classification The identity of the ancestors and closest relatives of the turtle lineage was a longstanding scientific mystery, though new discoveries and better analyses in the early 21st century began to clarify turtle relationships. Analysis of fossil data has shown that turtles are diapsid reptiles, most closely related either to the archosaurs (crocodiles, bird, and relatives) or the lepidosaurs (lizards, tuatara, and relatives). Genetic analysis strongly favors the hypothesis that turtles are the closest relatives of the archosaurs, though studies using only fossil evidence often continue to recover them as relatives of lepidosaurs. Studies using only fossils, as well as studies using a combination of fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosauromorpha
Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, lizards, and snakes). Archosauromorphs first appeared during the late Middle Permian or Late Permian, though they became much more common and diverse during the Triassic period. Although Archosauromorpha was first named in 1946, its membership did not become well-established until the 1980s. Currently Archosauromorpha encompasses four main groups of reptiles: the stocky, herbivorous allokotosaurs and rhynchosaurs, the hugely diverse Archosauriformes, and a polyphyletic grouping of various long-necked reptiles including ''Protorosaurus'', tanystropheids, and ''Prolacerta''. Other groups including pantestudines (turtles and their extinct relatives) and the semiaquatic choristoderes have also been placed in Archosauromorpha by some authors. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropterygia
Sauropterygia ("lizard flippers") is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria became extinct at the end of that period. The plesiosaurs would continue to diversify until the end of the Mesozoic. Sauropterygians are united by a radical adaptation of their pectoral girdle, adapted to support powerful flipper strokes. Some later sauropterygians, such as the pliosaurs, developed a similar mechanism in their pelvis. Uniquely among reptiles, sauropterygians moved their tail vertically like modern cetaceans and sirenians. Origins and evolution The earliest sauropterygians appeared about 247 million years ago (Ma), at the start of the Middle Triassic: the first definite sauropterygian with exact stratigraphic datum lies within the Spathian division of the Olenekian era in South China. Early examples were small (around 60 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauria
Sauria is the clade containing the most recent common ancestor of archosaurs (such as crocodilians, dinosaurs, etc.) and lepidosaurs ( lizards and kin), and all its descendants. Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria, Sauria can be considered the crown group of diapsids, or reptiles in general. Depending on the systematics, Sauria includes all modern reptiles or most of them (including birds, a type of archosaur) as well as various extinct groups. Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals. Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards, which before 1800 were considered crocodilians. Systematics Recent genomic studiesCrawford, Nicholas G., et al. "More than 1000 ultraconserved elements provide evidence that turtles are the sister g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropterygia
Sauropterygia ("lizard flippers") is an extinct taxon of diverse, aquatic reptiles that developed from terrestrial ancestors soon after the end-Permian extinction and flourished during the Triassic before all except for the Plesiosauria became extinct at the end of that period. The plesiosaurs would continue to diversify until the end of the Mesozoic. Sauropterygians are united by a radical adaptation of their pectoral girdle, adapted to support powerful flipper strokes. Some later sauropterygians, such as the pliosaurs, developed a similar mechanism in their pelvis. Uniquely among reptiles, sauropterygians moved their tail vertically like modern cetaceans and sirenians. Origins and evolution The earliest sauropterygians appeared about 247 million years ago (Ma), at the start of the Middle Triassic: the first definite sauropterygian with exact stratigraphic datum lies within the Spathian division of the Olenekian era in South China. Early examples were small (around 60 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pappochelys
''Pappochelys'' (''παπποχέλυς'' [πάππος (grandfather) + χέλυς (turtle)] meaning "grandfather turtle" in Ancient Greek, Greek) is an extinct genus of diapsid reptile possibly related to turtles. The genus contains only one species, ''Pappochelys rosinae'', from the Middle Triassic of Germany, which was named by paleontologists and Hans-Dieter Sues in 2015 in paleontology, 2015. The discovery of ''Pappochelys'' provides strong support for the placement of turtles within Diapsida, a hypothesis that has long been suggested by molecular data, but never previously by the fossil record. It is morphologically intermediate between the definite stem-turtle ''Odontochelys'' from the Late Triassic of China and ''Eunotosaurus'', a reptile from the Middle Permian of South Africa. Description ''Pappochelys'' had a wide body, small skull, and a long tail that makes up about half of the total body length, which is up to . The skull is pointed with large eye sockets. Several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eunotosaurus
''Eunotosaurus'' (''Latin'': Stout-backed lizard) is an extinct genus of amniote, possibly a close relative of turtles. ''Eunotosaurus'' lived in the late Middle Permian (Capitanian stage) and fossils can be found in the Karoo Supergroup of South Africa. ''Eunotosaurus'' resided in the swamps of southern Africa. Its ribs were wide and flat, forming broad plates similar to a primitive turtle shell, and the vertebrae were nearly identical to those of some turtles. Accordingly, it is often considered as a possible transitional fossil between turtles and their prehistoric ancestors. However, it is possible that these turtle-like features evolved independently of the same features in turtles, since other anatomical studies and phylogenetic analyses suggest that ''Eunotosaurus'' may instead have been a parareptile, an early-diverging neodiapsid unrelated to turtles, or a synapsid. Description ''Eunotosaurus'' reached up to in total body length. It had a broad body formed by nine pai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acerosodontosaurus
''Acerosodontosaurus'' is an extinct genus of neodiapsid reptiles that lived during the Upper Permian of Madagascar. The only species of ''Acerosodontosaurus'', ''A. piveteaui'', is known from a natural mold of a single partial skeleton including a crushed skull and part of the body and limbs. The fossil was discovered in marine deposits of the Lower Sakamena Formation. In conjunction with several skeletal characteristics, this may indicate that ''Acerosodontosaurus'' individuals were at least partially aquatic. ''Acerosodontosaurus'' has generally been considered a " younginiform", part of a paraphyletic grade of Permian diapsids which linked the most basal ("primitive") diapsids (araeoscelidians such as ''Petrolacosaurus'') to more derived ("advanced") diapsids, including the earliest ancestors of modern reptiles such as crocodilians and lizards. However, its position within the grade is controversial. Initially considered a specimen of the contemporaneous ''Tangasaurus'', '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odontochelys Semitestacea
''Odontochelys semitestacea'' (meaning "toothed turtle with a half-shell") is a Late Triassic relative of turtles. Before ''Pappochelys'' was discovered and ''Eunotosaurus'' was redescribed, ''Odontochelys'' was considered the oldest undisputed member of Pantestudines (i.e. a stem-turtle). It is the only known species in the genus ''Odontochelys'' and the family Odontochelyidae. Discovery ''Odontochelys semitestacea'' was first described from three 220-million-year-old specimens excavated in Triassic deposits in Guizhou, China. The locale of its discovery at one time was the Nanpanjiang Trough basin, a shallow marine environment surrounded on three sides by land. These deposits preserve an ecosystem known as the Guanling biota, which was dominated by marine reptiles. Description ''Odontochelys'' differed grossly from modern turtles. Modern turtles have a horny beak without teeth in their mouth. In contrast, ''Odontochelys'' fossils were found to have had teeth embedded in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odontochelys
''Odontochelys semitestacea'' (meaning "toothed turtle with a half-shell") is a Late Triassic relative of turtles. Before ''Pappochelys'' was discovered and ''Eunotosaurus'' was redescribed, ''Odontochelys'' was considered the oldest undisputed member of Pantestudines (i.e. a stem-turtle). It is the only known species in the genus ''Odontochelys'' and the family Odontochelyidae. Discovery ''Odontochelys semitestacea'' was first described from three 220-million-year-old specimens excavated in Triassic deposits in Guizhou, China. The locale of its discovery at one time was the Nanpanjiang Trough basin, a shallow marine environment surrounded on three sides by land. These deposits preserve an ecosystem known as the Guanling biota, which was dominated by marine reptiles. Description ''Odontochelys'' differed grossly from modern turtles. Modern turtles have a horny beak without teeth in their mouth. In contrast, ''Odontochelys'' fossils were found to have had teeth embedded in their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankylopoda
Ankylopoda was a proposed clade that hypothetically contains turtles and lepidosaurs (tuatara, lizards and snakes) and their fossil relatives. This clade is supported based on microRNAs as well as the fossil record. However, it was strongly contradicted by molecular evidence which supports Archelosauria. Classification The cladogram below follows the most likely result found by another analysis of turtle relationships, this one using only fossil evidence, published by Rainer Schoch and Hans-Dieter Sues in 2015. This study found ''Eunotosaurus'' to be an actual early stem-turtle, though other versions of the analysis found weak support for it as a parareptile. See also * Archelosauria Archelosauria is a clade grouping turtles and archosaurs (birds and crocodilians) and their fossil relatives, to the exclusion of lepidosaurs (the clade containing lizards, snakes and the tuatara). The majority of phylogenetic analyses based on m ..., an alternative clade that places turtles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parareptilia
Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). 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 ( bolosaurids such as ''Eudibamus''), the first reptiles with advanced hearing systems ( nycteroleterids and others), and the first large herbivorous reptiles (the pareiasaurs). 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eorhynchochelys
''Eorhynchochelys'' (meaning "dawn-beaked turtle" in Greek) is an extinct genus of stem-turtle from the Late Triassic Xiaowa Formation (or Wayao Member of the Falang Formation) of southwestern China. Description ''Eorhynchochelys'' is notable for its unusual combination of a turtle-style skull and a conventional reptilian body. The skull, for example, has an edentulous beak typical of all members of Testudinata. However, the thorax region is markedly different from ''Pappochelys'' and ''Odontochelys'' and more similar to ''Eunotosaurus ''Eunotosaurus'' (''Latin'': Stout-backed lizard) is an extinct genus of amniote, possibly a close relative of turtles. ''Eunotosaurus'' lived in the late Middle Permian (Capitanian stage) and fossils can be found in the Karoo Supergroup of Sout ...'' in lacking a shell, even though the ribs were wide and flat. The skull also has a single pair of holes behind the skull, unlike the presence of two pairs of holes in ''Pappochelys''. Unlike other s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
