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Crocodyliform
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, Michael J. Benton and James M. Clark argued that all 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. 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 Tetrapods, volume 1''. Oxford: Cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kemkemia
''Kemkemia'' is a genus of probable crocodyliforms living in the Cretaceous, described from a single fossil that was recovered in 1999 from Morocco by an Italian team searching for fossil invertebrates. The fossil of ''Kemkemia'' dates from the Cenomanian age. History The type species, ''Kemkemia auditorei'', was named and described in 2009 by Italian paleontologists Andrea Cau and Simone Maganuco and is based on a single distal caudal vertebra, MSNM V6408. This vertebra measures 60.48 mm in length and 33.81 mm in height. The genus name refers to the Kem Kem Beds and the specific name honours Italian paleontological illustrator Marco Auditore. Description The describers, because of the general morphology of the vertebra, especially the strongly developed neural spine, originally considered it likely that ''K. auditorei'' was a theropod dinosaur belonging to the group Neoceratosauria. In view of the limited remains, they cautiously assigned it to a more gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. 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 morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originated pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eopneumatosuchus
''Eopneumatosuchus'' is an extinct genus of basal crocodyliform. Fossils have been found from two localities within the Kayenta Formation of Arizona. Both localities are around 20 miles southeast of the Grand Canyon and in close proximity to one another. The localities probably date back to the Early Jurassic, most likely during the Sinemurian stage. Classification ''Eopneumatosuchus'' was initially considered to be a protosuchian, first proposed when the genus was named in 1980. However, this classification was later questioned on the basis of several features of the holotype material, and as a result it is no longer considered to be within Protosuchia. Particular features of the posterior part of the cranium, the only material associated with the genus, suggest that ''Eopneumatosuchus'' may have close relations with Early Jurassic teleosaurs. The large supratemporal fenestrae of ''Eopneumatosuchus'' are characteristic of longirostrine crocodilians. Despite the similar crani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entradasuchus
''Entradasuchus'' (meaning "Entrada andstone and Ranchcrocodile") is a genus of crocodyliform, an early member of the group including crocodilians. The only known specimen was found in rocks of the Middle Jurassic Entrada Sandstone of Entrada Ranch, Grand County, Utah. Middle Jurassic terrestrial tetrapods are very rare, and ''Entradasuchus'' was the first unequivocal North American Middle Jurassic nonmarine tetrapod known from body fossils when it was described (1995). Description ''Entradasuchus'' is based on CU-MWC 183-11, a skeleton including at least the upper surfaces of the skull, articulated armor scutes from the neck to the tail, and some limb bones, all preserved in top (dorsal) view. The exact composition of the specimen was unknown at the time of its description, because it is preserved in sandstone that is harder than the calcite that has replaced the bones, which makes preparation difficult. Additionally, much of the visible part of the skeleton is repr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notochampsa
''Notochampsa'' is an extinct genus of protosuchian crocodylomorph. Fossils have been found from the lower Clarens Formation of the Karoo Supergroup in South Africa, dating back to the Pliensbachian stage of the Early Jurassic. ''Notochampsa'' comes from a period of relative fossil scarcity, and is the youngest known occurrence of a crocodylomorph (and vertebrate body fossil) from the Karoo Basin of South Africa. Taxonomy The genus was named in a paper published in 1904 by Robert Broom. The type species was named ''N. istedana'', and a second species, named ''N. longipes'', was also described. Later in 1924, ''N. longipes'' was given its own genus, ''Erythrochampsa''. In that paper, Sidney Haughton created the family Notochampsidae for ''Notochampsa''. Notochampsa was later used to include other genera of protosuchians such as '' Dyoplax'', ''Pedeticosaurus'', '' Platyognathus'', and '' Protosuchus'', and later '' Microchampsa'' and ''Orthosuchus''. ''Notochampsa'' had also once ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthosuchus
''Orthosuchus'' (meaning "straight crocodile") is an extinct genus of protosuchian crocodyliform that lived during the Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ..., about 196 million years ago. It was first discovered in 1963 in the Red Beds Formation in the Qacha's Nek Province of Lesotho, southern Africa. The characteristics showed on its postcranial skeleton and the skull indicated that it is a Crocodyliformes, Crocodyliform.Nash, Diane. "A Crocodile from the Upper Triassic of Lesotho." ''Journal of Zoology''. Blackwell Publishing Ltd, 20 Aug. 2009. Web. 05 Mar. 2017. The finding is significant since some of the characteristics found on this specimen were believed to be absent until Jurassic. Description ''Orthosuchus'' has a body proportion similar to l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria. Members of the order's total group, the clade Pseudosuchia, appeared about 250 million years ago in the Early Triassic period, and diversified during the Mesozoic era. The order Crocodilia 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, crocodilians is a less ambiguous vernacular term for members of this group. Large, solidly built, lizard-like reptiles, crocodilians have long flattened snouts, laterally compressed tails, and eyes, ears, and nostrils at the top of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gobiosuchidae
Gobiosuchidae is a family of Cretaceous crocodyliforms known from Mongolia and Spain. Genera Three genera are currently classified within Gobiosuchidae: ''Cassissuchus'', ''Gobiosuchus'', and ''Zaraasuchus''.Ángela D. Buscalioni (2017) The Gobiosuchidae in the early evolution of Crocodyliformes. Journal of Vertebrate Paleontology Article: e1324459 doi: https://dx.doi.org/10.1080/02724634.2017.1324459 http://www.tandfonline.com/doi/full/10.1080/02724634.2017.1324459 Synapomorphies According to Pol & Norell (2004), gobiosuchids form a clade united by the following synapomorphies: * Parietal without broad occipital portion * Absence of external mandibular fenestra * More than two parallel rows of dorsal osteoderms * Cranial table as wide as ventral portion of skull * Palpebrals sutured to each other and the frontal, excluding it from the orbital margin * External surface of ascending process of jugal exposed posterolaterally * Longitudinal ridge on lateral surface of juga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tagarosuchus
''Tagarosuchus'' is an extinct genus of Early Cretaceous protosuchian-grade crocodyliform. Fossils of ''Tagarosuchus'' have been found from southern Siberia, including a nearly complete skull found near the village of Shestakovo in Kemerovo Oblast. ''Tagarosuchus'' was named in 1999, with the type species being ''T. kulemzini''. Remains have been recovered from the Aptian-Albian Ilek Formation. Paleoecology A diverse vertebrate assemblage has been uncovered from the Shestakovo locality. ''Tagarosuchus'' would have coexisted with paramacellodid, scincomorphan, and xenosaurid lizards, the shartegosuchid crocodyliform ''Kyasuchus'', the tritylodontid cynodont '' Xenocretosuchus'', the triconodont mammal ''Gobiconodon'', the ceratopsian dinosaur ''Psittacosaurus'', troodontid theropod dinosaurs, and sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoeucrocodylia
Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that Mesosuchia was an evolutionary grade, a hypothesis confirmed by the phylogenetic analysis of Benton and Clark (1988) which demonstrated that Eusuchia (which includes all living crocodylian species) was nested within Mesosuchia. Due to the paraphyly of Mesosuchia, Mesoeucrocodylia was erected to replace Mesosuchia. Several anatomical characteristics differentiate Mesoeucrocodylia from the other crocodylomorph clades. The frontal bones of the skull are fused together into a single compound element, for example. Mesoeucrocodylians possess something of a secondary palate, formed by the posterior extension of sutured palatine bones. The otic aperture of the members of this clade is blocked posteriorly by the squamosal bone. Classification Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Clade
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alligator
An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additionally, several extinct species of alligator are known from fossil remains. Alligators first appeared during the Oligocene epoch about 37 million years ago. The name "alligator" is probably an anglicized form of ', the Spanish term for "the lizard", which early Spanish explorers and settlers in Florida called the alligator. Later English spellings of the name included ''allagarta'' and ''alagarto''. Evolution Alligators and caimans split in North America during the early Tertiary or late Cretaceous (about 53 million to about 65 million years ago). The Chinese alligator split from the American alligator about 33 million years ago and probably descended from a lineage that crossed the Bering land bridge during the Neogene. The modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
