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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] |
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] |
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 molecular data (e.g. DNA and proteins) have supported a sister-group relationship between turtles and archosaurs. On the other hand, Archelosauria has not been supported by most morphological analyses, which have instead found turtles to either be descendants of parareptiles, early-diverging diapsids outside of Sauria, or close relatives of lepidosaurs within the clade Ankylopoda. Classification Multiple sequence alignments of DNA and protein sequences and phylogenetic inferences have shown that turtles are the closest living relatives to birds and crocodilians. There are about 1000 ultra-conserved elements in the genome that are unique to turtles and archosaurs, but which are not found in lepidosaurs. Other genome-wide analyses also sup ... [...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] |
Lepidosauromorpha
Lepidosauromorpha (in PhyloCode known as ''Pan-Lepidosauria'') is a group of reptiles comprising all diapsids closer to lizards than to archosaurs (which include crocodiles and birds). 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. Lepidosauromorphs are distinguishable from archosauromorphs (reptiles closer to archosaurs) by their primitive sprawling gait (allowing for the same sinusoidal trunk and tail movement seen in fish), the sliding "joint" between the coracoids and the sternum (for a longer stride), and their pleurodont dentition. In contrast, Archosauromorphs possess a parasagittal gait, a reduction in their dermal girdle, a reduction and/or loss of the sternum, and a more thecodont dentition. Living lepidosauromorphs have retained an ectothermic (" cold blooded") metabolism, unlike the ancestral condition in archosauromorphs ... [...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] |
Placodontia
Placodonts (" Tablet teeth") are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generally between in length, with some of the largest measuring long. The first specimen was discovered in 1830. They have been found throughout central Europe, North Africa, the Middle East and China. Palaeobiology The earliest forms, like ''Placodus'', which lived in the early to middle Triassic, resembled barrel-bodied lizards superficially similar to the marine iguana of today, but larger. In contrast to the marine iguana, which feeds on algae, the placodonts ate molluscs and so their teeth were flat and tough to crush shells. In the earliest periods, their size was probably enough to keep away the top sea predators of the time: the sharks. However, as time passed, other kinds of carnivorous reptiles began to colonize the seas, such as ich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosauropterygia
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&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a unit in chronostratigraphy. The Early Triassic is the oldest epoch of the Mesozoic Era. It is preceded by the Lopingian Epoch (late Permian, Paleozoic Era) and followed by the Middle Triassic Epoch. The Early Triassic is divided into the Induan and Olenekian ages. The Induan is subdivided into the Griesbachian and Dienerian subages and the Olenekian is subdivided into the Smithian and Spathian subages. The Lower Triassic series is coeval with the Scythian Stage, which is today not included in the official timescales but can be found in older literature. In Europe, most of the Lower Triassic is composed of Buntsandstein, a lithostratigraphic unit of continental red beds. The Early Triassic and partly also the Middle Triassic span the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proganochelys
''Proganochelys'' is an extinct, primitive stem-turtle that has been hypothesized to be the sister taxon to all other turtles creating a monophyletic group, the ''Casichelydia''. ''Proganochelys'' was named by Georg Baur in 1887 as the oldest turtle in existence at the time. The name ''Proganochelys'' comes from the Greek word ''ganos'' meaning 'brightness', combined with prefix ''pro'', 'before', and Greek base ''chelys'' meaning 'turtle'. ''Proganochelys'' is believed to have been around 1 meter in size and herbivorous in nature. ''Proganochelys'' was known as the most primitive stem-turtle for over a century, until the novel discovery of ''Odontochelys'' in 2008. ''Odontochelys'' and ''Proganochelys'' share unique primitive features that are not found in ''Casichelydia'', such as teeth on the pterygoid and vomer and a plate-like coracoid. ''Proganochelys'' is the oldest stem-turtle species with a complete shell discovered to date, known from fossils found in Germany, Switzerla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testudinata
Testudinata is the group of all tetrapods with a true turtle shell. It includes both modern turtles (Testudines) and many of their extinct, shelled relatives (stem-turtles). Though it was first coined as the group containing turtles by Jacob Theodor Klein in 1760, it was first defined in the modern sense by Joyce and colleagues in 2004. Testudinata does not include the primitive stem-turtle ''Odontochelys'', which only had the bottom half of a shell. A recent phylogenetic tree of Testudinata included Angolachelonia and Testudines Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ... as sister-taxa and subgroups of Testudinata. Classification The cladogram below follows an analysis by Jérémy Anquetin in 2012. References {{Taxonbar, from=Q16114972 Reptile taxonomy Norian f ... [...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] |
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] |
