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Crocodylomorphs
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ecologically diverse than modern crocodillians. The earliest and most primitive crocodylomorphs are represented by " sphenosuchians", a paraphyletic assemblage containing small-bodied, slender forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, crocodylomorphs morphologically diversified into numerous niches, with the subgroups Neosuchia (which includes modern crocodilians) and the extinct Thalattosuchia adapting to aquatic life, while some terrestrial groups adopted herbivorous and omnivorous lifestyles. Terrestrial crocodylomorphs would continue to co-exist alongside aquatic forms until becoming extinct duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic–Jurassic Extinction Event
The Triassic–Jurassic (Tr-J) extinction event (TJME), often called the end-Triassic extinction, marks the boundary between the Triassic and Jurassic periods, . It represents one of five major extinction events during the Phanerozoic, profoundly affecting life on land and in the oceans. In the seas, about 23–34% of marine genus, genera disappeared; Coral, corals, Bivalvia, bivalves, Brachiopod, brachiopods, Bryozoa, bryozoans, and Radiolaria, radiolarians suffered severe losses of diversity and Conodont, conodonts were completely wiped out, while marine vertebrates, Gastropoda, gastropods, and benthic foraminifera were relatively unaffected. On land, all Archosauromorpha, archosauromorph reptiles other than Crocodylomorpha, crocodylomorphs, dinosaurs, and pterosaurs became extinct. Crocodylomorphs, dinosaurs, pterosaurs, and mammals were left largely untouched, allowing them to become the dominant land animals for the next 135 million years. Plants were likewise significantly a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodilia
Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchian, a subset of archosaurs that appeared about 235 million years ago and were the only survivors of the Triassic–Jurassic extinction event. While other crocodylomorph groups further survived the Cretaceous–Paleogene extinction event, notably sebecosuchians, only the crocodilians have survived into the Quaternary. The order includes the true crocodiles (family Crocodylidae), the alligators and caimans (family Alligatoridae), and the gharial and false gharial (family Gavialidae). Although the term "crocodiles" is sometimes used to refer to all of these families, the term "crocodilians" is less ambiguous. Extant crocodilians have flat heads with long snouts and tails that are compressed on the sides, with their eyes, ears, and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaur
Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics, cladistic sense of the term includes all living and extinct relatives of birds and crocodilians such as non-avian dinosaurs, pterosaurs, phytosaurs, aetosaurs and rauisuchians as well as many marine reptile#Extinct groups, Mesozoic marine reptiles. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives; and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphology (biology), morphological ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudosuchia
Pseudosuchia, from Ancient Greek ψεύδος (''pseúdos)'', meaning "false", and σούχος (''soúkhos''), meaning "crocodile" is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs", in contrast to the "bird-line archosaurs" or Avemetatarsalia. Despite Pseudosuchia meaning "false crocodiles", the name is a misnomer as true crocodilians are now defined as a subset of the group. The clade Pseudosuchia is potentially equivalent to another term, Crurotarsi, even though the latter has a different, Node-based taxon, node-based definition: "all taxa the least inclusive clade containing ''Rutiodon carolinensis'' (Emmons, 1856), and ''Crocodylus niloticus'' (Laurenti, 1768)." Many paleontologists of the late 20th century took this proposal for granted, using Crurotarsi as the term for crocodilian ancestors. In 2011, a m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Junggarsuchus
''Junggarsuchus'' () is an extinct genus of sphenosuchian crocodylomorpha, crocodylomorph from the Middle Jurassic, Middle or Late Jurassic period of China. The type species, type and only species is ''J. sloani''. The Genus, generic name of ''Junggarsuchus'' comes from the Junggar Basin (the anglicization of Dzungaria, Dzungar), where the fossil was found, and the Greek (language), Greek word "''souchos''" meaning crocodile. The specific name, "''sloani''" is in honor of C. Sloan, who is credited with finding the holotype. Discovery ''Junggarsuchus'' was found in the upper part of the Lower Member of the Shishugou Formation in Xinjiang, China at the Wucaiwan locality. The type and only specimen was described in 2004 by James Clark, Xu Xing (paleontologist), Xu Xing, Catherine Forester, and Yuan Wang in ''Nature (journal), Nature'', but it did not receive a full osteological description until 2022 when Alexander Ruebenstahl, Michael Klein, and Yi Hongyu published a monograph along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saltoposuchus
''Saltoposuchus'' is an extinct genus of small (1–1.5 m and 10–15 kg), long-tailed crocodylomorph reptile (Sphenosuchia), from the Norian (Late Triassic) of Europe. The name translated means "leaping foot crocodile". It has been proposed that ''Terrestrisuchus gracilis'' and ''Saltoposuchus connectens'' represent different ontogenetic stages of the same genus. ''Saltoposuchus'' was commonly (and incorrectly) referred to in popular literature as the ancestor (or close ancestors) to dinosaurs; however, recent scientific research shows that this is not the case. Description and paleobiology Fossil evidence of Sphenosuchia and early crocodylomorphs lead paleontologists to conclude that ''Saltoposuchus'' is a terrestrial animal. As a monophyletic group of crocodylomorphs, Saltoposuchidae have many key morphological traits shared with most crocodylomorphs. Skull Much like other crocodylomorphs, ''Saltoposuchus'' skulls had a (reduced) antorbital fenestra, an overhanging ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', ''Herrerasaurus'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trialestes
''Trialestes'' is an extinct genus of Late Triassic (Carnian) crocodylomorphs that lived in South America. It has been classified as a dinosaur in the past due it being adapted as a terrestrial, running carnivore. It is classified in Sphenosuchia, which were early relatives of crocodylians. Irmis, Nesbitt and Sues (2013) noted that some of the material referred to this taxon is actually dinosaurian; however, according to the authors, the holotype specimen PVL 2561, found in the Cancha de Bochas Member of the Ischigualasto Formation The Ischigualasto Formation is a Late Triassic geological formation in the Ischigualasto-Villa Unión Basin of southwestern La Rioja Province, Argentina, La Rioja Province and northeastern San Juan Province, Argentina, San Juan Province in northw ... in the Ischigualasto-Villa Unión Basin in northwestern Argentina, "comprises a single individual that preserves unambiguous crocodylomorph synapomorphies", indicating it is indeed a crocodylomorph, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenosuchia
Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, a group which includes all living crocodilians. Stratigraphic range The earliest known members of the group (i.e. '' Hesperosuchus'') are early Norian in age, found in the Blue Mesa Member of the Chinle Formation. Only one sphenosuchian is currently known from the Middle Jurassic, '' Junggarsuchus'', from the Junggar Basin ( Shishugou Formation) of China during either the Bathonian or the Callovian (~165 Ma) age,Clark, J.M., ''et al.'' (2004A Middle Jurassic 'sphenosuchian' from China and the origin of the crocodylian skull''Nature'' 430:1021-1024. and the Hallopodidae are known from the Late Jurassic of North America. Phylogeny The monophyly of the group is debated, although several synapomorphies characterize the clade, includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodyliformes
Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudosuchians to survive the K-Pg extinction event. In 1988, James M. Clark argued that traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for natural groups comprising all living members of any given lineage and descendants of their closest common ancestor. This posed a problem for the crocodilians, because the name Crocodylia, while used in various ways by various scientists, had always included not only living crocodilians but many of their extinct ancestors known only from the fossil record.Benton, M.J. and Clark, J.M. (1988). "Archosaur phylogeny and the relationships of the Crocodylia." Pp. 295–338 in Benton, M.J. (ed.), ''The phylogeny and classification of the Tetrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalattosuchia
Thalattosuchia is a clade of mostly marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution. They are colloquially referred to as marine crocodiles or sea crocodiles, though they are not members of Crocodilia and records from Thailand and China suggest that some members lived in freshwater. The clade contains two major subgroupings, the Teleosauroidea and Metriorhynchoidea. Teleosauroids are not greatly specialised for oceanic life, with back osteoderms similar to other crocodyliformes. Within Metriorhynchoidea, the Metriorhynchidae displayed extreme adaptions for life in the open ocean, including the transformation of limbs into flippers, the development of a tail fluke, and smooth, scaleless skin, and probably gave Viviparity, live birth, seemingly uniquely among archosaurs. Taxonomy The term Thalattosuchia was coined by Fraas in 1901.Fraas E. 1901. Die Meerkrokodile (Thalattosuchia n. g.) eine neue Sauriergruppe der Juraform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
