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Etjosuchus
''Etjosuchus'' is an extinct genus of " rauisuchian" (loricatan) archosaur from the Triassic of Namibia. It is known from a single species, ''Etjosuchus recurvidens'', which is based on a partial skeleton from the Ladinian or Carnian-age Omingonde Formation. Classification To evaluate the evolutionary position of ''Etjosuchus'' in a modern context, Tolchard ''et al.'' (2021) coded it into a phylogenetic matrix derived from the work of Nesbitt (2011). The phylogenetic analysis was run with several levels of implied weighting (from no weighting to k=1, 3, and 6), a strategy to minimize the effects of homoplasy (convergent evolution). With no weighting, ''Etjosuchus'' is resolved as a basal loricatan closer to crocodylomorphs than ''Luperosuchus'', but not as close as a ''Heptasuchus'' + ''Batrachotomus'' clade. At k=1, its position shifts crownward towards crocodylomorphs, and ''Etjosuchus'' may clade with ''Fasolasuchus'' and/or ''Rauisuchus''. Increasing the weighting furt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rauisuchia
"Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilia 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 ...ns than to birds and other dinosaurs. First named in the 1940s, Rauisuchia was a name exclusive to Triassic archosaurs which were generally large (often ), carnivorous, and quadrupedal with a pillar-erect hip posture, though exceptions exist for all of these traits. Rauisuchians, as a traditional Taxonomy, taxonomic group, were considered distinct from other Triassic archosaur groups such as early dinosaurs, Phytosaur, phytosaurs (crocodile-like carnivores), Aetosaur, aetosaurs (armored herbivor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loricata
Loricata is a clade of archosaur reptiles that includes crocodilians and some of their Triassic relatives, such as ''Postosuchus'' and ''Prestosuchus''. More specifically, Loricata includes Crocodylomorpha (the persistent archosaur subset which crocodilians belong to) and most "rauisuchians", a paraphyletic grade of large terrestrial pseudosuchians which were alive in the Triassic period and ancestral to crocodylomorphs. Loricata is one branch of the group Paracrocodylomorpha; the other branch is the clade Poposauroidea, an unusual collection of strange "rauisuchians" including bipedal, herbivorous, and sail-backed forms. The vast majority of typical "rauisuchians", which were usually quadrupedal predators, occupy basal (early-branching) rungs of Loricata leading up to crocodylomorphs. History and Classification Loricata was initially named in a completely different context by German naturalist Blasius Merrem in his 1820 ''Versuch eines Systems der Amphibien''. Merrem consid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and Ma (million years ago). It is preceded by the Early Triassic Epoch and followed by the Late Triassic Epoch. The Middle Triassic is divided into the Anisian and Ladinian ages or stages. Formerly the middle series in the Triassic was also known as Muschelkalk. This name is now only used for a specific unit of rock strata with approximately Middle Triassic age, found in western Europe. Middle Triassic fauna Following the Permian–Triassic extinction event, the most devastating of all mass-extinctions, life recovered slowly. In the Middle Triassic, many groups of organisms reached higher diversity again, such as the marine reptiles (e.g. ichthyosaurs, sauropterygians, thallatosaurs), ray-finned fish and many invertebrate groups like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postosuchus
''Postosuchus'', meaning "Crocodile from Post", is an extinct genus of rauisuchid reptiles comprising two species, ''P. kirkpatricki'' and ''P. alisonae'', that lived in what is now North America during the Late Triassic. ''Postosuchus'' is a member of the clade Pseudosuchia, the lineage of archosaurs that includes modern crocodilians (the other main group of archosaurs is Avemetatarsalia, the lineage that includes non-avian dinosaurs and their descendants, birds). Its name refers to Post Quarry, a place in Texas where many fossils of the type species, ''P. kirkpatricki'', were found. It was one of the apex predators of its area during the Triassic, larger than the small dinosaur predators of its time (such as ''Coelophysis''). It was a hunter which probably preyed on large bulky herbivores like dicynodonts and many other creatures smaller than itself (such as early dinosaurs). The skeleton of ''Postosuchus'' is large and robust with a deep skull and a long tail. It was a large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Grade
A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit. Definition An evolutionary grade is a group of species united by morphological or physiological traits, that has given rise to another group that has major differences from the ancestral condition, and is thus not considered part of the ancestral group, while still having enough similarities that we can group them under the same clade. The ancestral group will not be phylogenetically complete (i.e. will not form a clade), so will represent a paraphyletic taxon. In order to fully understand evolutionary grades, one must first get a better understanding of Phylogenetics, defined as "''In biology, is the study of the evolutionary history and relationships among individuals or groups of organisms (e.g. species, or populations). These relationships are discovered through phylogenetic i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (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 was coined by Willi Hennig to apply to well-known taxa like Reptilia ( reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor, including all extant reptiles as well as the extinct synapsids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rauisuchidae
Rauisuchidae is a group of large (up to or more) predatory Triassic archosaurs. There is some disagreement over which genera should be included in Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed whether these should even be thought of as separate valid families. Rauisuchids occurred throughout much of the Triassic, and may have first occurred in the Early Triassic if some archosaurian taxa such as ''Scythosuchus'' and ''Tsylmosuchus'' are considered to be within the family. An early cladistic analysis of crocodylotarsan (pseudosuchian) archosaurs included ''Lotosaurus ''Lotosaurus'' is an extinct genus of sail-backed poposauroid Poposauroidea is a clade of advanced pseudosuchians (archosaurs closer to crocodilians than to dinosaurs). It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual ...'', ''Fasolasuchus'', ''Rauisuchus'', and "the Kupferzell rauisuchid" (later called ''Batrachotomus'') within Rauisuchidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rauisuchus
''Rauisuchus'' (meaning "Wilhelm Rau's crocodile") is a genus of extinct archosaurs which lived in what is now the Geopark of Paleorrota (Santa María Formation), Brazil, during the Late Triassic period (235–228 million years ago). It contains one species, ''R. tiradentes''.''Rauisuchus'' at Fossilworks.orgF. v. Huene. (1942) ''Die fossilen Reptilien des südamerikanischen Gondwanalandes. Ergebnisse der Sauriergrabung in Südbrasilien 1928/29.'' München: C.H. Beck'sche Verlagsbuchhandlung Discovery and naming In 1928 or 1929, near the road from Sa ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fasolasuchus
''Fasolasuchus'' is an extinct genus of loricatan. Fossils have been found in the Los Colorados Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina that date back to the Norian stage of the Late Triassic, making it one of the last rauisuchians to have existed before the order became extinct at the end of the Triassic. Description It is quite possibly the largest known member of Rauisuchia, with an estimated length of to , even bigger than the prestosuchid ''Saurosuchus'' at in length. This would make ''Fasolasuchus'' the largest terrestrial predator to have ever existed save for large theropods. Like ''Saurosuchus'', it had only a single row of caudal osteoderms, unusual among rauisuchians. It also had a hyposphene-hypantrum articulation that gave the vertebral column extra rigidity. This feature is also seen in several other rauisuchians such as ''Postosuchus'' as well as saurischian dinosaurs. Phylogeny Cladogram after the analysis of Nesbitt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Group
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 gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
