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Portugalosuchus
''Portugalosuchus'' (meaning "crocodile from Portugal") is an extinct genus of eusuchian crocodyliform that was possibly a basal crocodylian – if so then it would be the oldest known crocodylian to date. The type species is ''P. azenhae'', described in 2018, and it is known from the Late Cretaceous (Cenomanian)-aged Tentugal Formation in Portugal. A 2021 morphological study recovered ''Portugalosuchus'' within Crocodylia as a member of Gavialidae closely related to similar "thoracosaurs" (e.g. ''Thoracosaurus''), while also noting that is might also possibly be outside of Crocodylia completely. A 2022 tip dating analysis incorporating both morphological and DNA data placed ''Portugalosuchus'' outside of Crocodylia, as the sister taxon of the family Allodaposuchidae. A cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eusuchia
Eusuchia is a clade of crocodylomorphs that first appeared in the Early Cretaceous with ''Hylaeochampsa''. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-T extinction. Since the other two clades died out 47 and 11 million years ago respectively, all living crocodilian species are eusuchians, as are many extinct forms. Definition Eusuchia was originally defined by Thomas Henry Huxley in 1875 as an apomorphy-based group, meaning that it was defined by shared characteristics rather than relations. These characteristics include pterygoid-bounded choanae and vertebrae which are procoelous (concave from the front and convex from the back). The possibility that these traits may have been convergently evolved in different groups of neosuchians rather than one lineage spurred some modern paleontologists to revise the group's definition to make it defined solely by relations. In 1999, Christopher Brochu redefined Eusuchia as "the last common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 In Archosaur Paleontology
The year 2018 in archosaur paleontology was eventful. Archosaurs include the only living dinosaur group — birds — and the reptile crocodilians, plus all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs. Archosaur palaeontology is the scientific study of those animals, especially as they existed before the Holocene Epoch began about 11,700 years ago. The year 2018 in paleontology included various significant developments regarding archosaurs. This article records new taxa of fossil archosaurs of every kind that have been described during the year 2018, as well as other significant discoveries and events related to paleontology of archosaurs that occurred in the year 2018. General research * A study on the morphology of dorsal vertebrae of extant and fossil archosaurs, and on its implications for inferring lung structure in non-avian dinosauriform archosaurs, is published by Brocklehurst, Schachner & Sellers (2018). * A study on the hip joint mobility of the ext ... [...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] |
Eusuchia
Eusuchia is a clade of crocodylomorphs that first appeared in the Early Cretaceous with ''Hylaeochampsa''. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survived the K-T extinction. Since the other two clades died out 47 and 11 million years ago respectively, all living crocodilian species are eusuchians, as are many extinct forms. Definition Eusuchia was originally defined by Thomas Henry Huxley in 1875 as an apomorphy-based group, meaning that it was defined by shared characteristics rather than relations. These characteristics include pterygoid-bounded choanae and vertebrae which are procoelous (concave from the front and convex from the back). The possibility that these traits may have been convergently evolved in different groups of neosuchians rather than one lineage spurred some modern paleontologists to revise the group's definition to make it defined solely by relations. In 1999, Christopher Brochu redefined Eusuchia as "the last common ... [...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] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tip Dating
Tip dating is a technique used in molecular dating that allows the inference of time-calibrated phylogenetic trees. Its defining feature is that it uses the ages of the samples to provide time information for the analysis, in contrast with traditional 'node dating' methods that require age constraints to be applied to the internal nodes of the evolutionary tree. In tip dating, morphological data and molecular data are typically analysed together to estimate the evolutionary relationships (tree topology) and the divergence times among lineages (node times); this approach is also known as 'total-evidence dating'. However, tip dating can also be used to analyse data sets that only comprise morphological characters or that only comprise molecular characters (e.g., data sets that include samples of ancient DNA or of serially sampled viruses). Tip dating has been implemented in Bayesian phylogenetic software and typically draws on the fossilised birth-death model for evolution. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allodaposuchidae
Allodaposuchidae is an extinct clade of eusuchians that lived in Europe during the Late Cretaceous (Santonian-Maastrichtian). Systematics The type genus, ''Allodaposuchus'', was originally described in 1928 by Nopcsa from the Maastrichtian-age Sard Formation of the Hațeg Basin in Transylvania, Romania, and classified as a relative of the North American ''Leidyosuchus''. It was later classified as a eusuchian outside of Crocodylia in a 2001 paper, and subsequent studies found a number of European eusuchian species ('' Arenysuchus'', '' Ischyrochampsa'', '' Massaliasuchus'', ''Musturzabalsuchus'') to group with ''Allodaposuchus'', prompting the erection of the clade Allodaposuchidae to accommodate ''Allodaposuchus'' and all European eusuchians closely related to it. Narváez ''et al.'' cladistically defined Allodaposuchidae in 2015 as '' Allodaposuchus precedens'' and all crocodyliforms more closely related to it than to ''Hylaeochampsa vectiana'', '' Shamosuchus djadochtaensis' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acynodon
''Acynodon'' is an extinct genus of eusuchian crocodylomorph from the Late Cretaceous, with fossils found throughout Southern Europe. Classification The genus ''Acynodon'' contains three species: ''A. iberoccitanus'', ''A. adriaticus'', and ''A. lopezi''. Fossils have been found in France, Spain, Italy, and Romania, dating back to the Santonian and Maastrichtian periods of the Late Cretaceous. When first described in 1997, it was placed within the family Alligatoridae. New findings a decade later led to it being reclassified as a basal globidontan. Recent studies have since resolved ''Acynodon'' as a basal eusuchian crocodylomorph, outside of the Crocodylia crown group, and a close relative to ''Hylaeochampsa''. Description The skull of ''Acynodon'' is extremely brevirostrine; it had a very short and broad snout compared to other known alligatorids. Its dentition was quite derived, with enlarged molariform teeth and a lack of maxillary and dentary In anatomy, the mandible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hylaeochampsa
''Hylaeochampsa'' is an extinct genus of eusuchian crocodylomorphs. It is known only from a partial skull recovered from Barremian-age rocks of the Lower Cretaceous Vectis Formation (Wealden Group) of the Isle of Wight. This skull, BMNH R 177, is short and wide, with a eusuchian-like palate and inferred enlarged posterior teeth that would have been suitable for crushing.Owen, R. (1874). Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Supplement no. V. Dinosauria (''Iguanodon''). ealden and Purbeck. ''The Palaeontographical Society, London'' 1873:1-18 ''Hylaochampsa'' was described by Richard Owen in 1874, with ''H. vectiana'' as the type species. It may be the same genus as the slightly older ''Heterosuchus'', inferred to have been of similar evolutionary grade, but there is no overlapping material as ''Heterosuchus'' is known only from vertebrae. If the two could be shown to be synonyms, ''Hylaeochampsa'' would have priority because it is the older name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iharkutosuchus
''Iharkutosuchus'' (" Iharkút crocodile", after where it was found) is an extinct genus of basal eusuchian crocodyliform. Its fossils have been found in the Santonian-age Upper Cretaceous Csehbánya Formation in the Bakony Mountains of western Hungary. Description It is based on MTM 2006.52.1, a nearly complete skull, and several other partial skulls, isolated skull bones, and numerous teeth are also known. ''Iharkutosuchus'' was a small crocodyliform (skull length , estimated body length ). Its skull was low, and the snout was short. ''Iharkutosuchus'' is unusual in its heterodonty: some of its teeth were complex and multicusped, like mammal teeth. The structure of the skull indicates that it could grind food with a mobile lower jaw, and together with the teeth suggest a diet of fibrous plant material. Classification The genus was described in 2007 by Attila Ősi and colleagues. The type species is ''I. makadii'', named for László Makádi. A 2011 phylogenetic stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
