Neosuchia is a clade within Mesoeucrocodylia that includes all modern extant crocodilians and their closest fossil relatives. It is defined as the most inclusive clade containing all crocodylomorphs more closely related to Crocodylus niloticus (the Nile Crocodile) than to Notosuchus terrestris. Neosuchia is very diverse and may be polyphyletic, as the clade has undergone many revisions since it was first named in 1988. Neosuchians first appear in the Early Jurassic with the earliest known goniopholid Calsoyasuchus, which lived during the Sinemurian and Pliensbachian stages.
|Suborders & Families|
In 2012, paleontologists Mario Bronzati, Felipe Chinaglia Montefeltro, and Max C. Langer conducted a broad phylogenetic analysis to produce supertrees of Crocodyliformes, including 184 species. The most parsimonious trees were highly resolved, meaning the phylogenetic relationships found in the analysis were highly likely. Below is a consensus tree from the study:
Adzhosuchus is an extinct genus of crocodylomorph in the family Shartegosuchidae. Fossils have been found from southwestern Mongolia that date back to the Late Jurassic period.Almadasuchus
Almadasuchus is an extinct genus of crocodylomorph known from the early Late Jurassic (early Oxfordian stage) Puesto Almada Member of the Cañadón Asfalto Formation of Patagonia, Argentina. It contains a single species, Almadasuchus figarii. It is known from the holotype MPEF-PV 3838, a well-preserved posterior region of the skull as well as other skull and postcranial remains.Atoposauridae
Atoposauridae is a family of crocodile-line archosaurs belonging to Neosuchia. The majority of the family are known from Late Jurassic to Early Cretaceous marine deposits in France, Portugal, and Bavaria in southern Germany. The discovery of the genus Aprosuchus, however, extends the duration of the lineage to the end of the Cretaceous in Romania.Coelognathosuchia
Coelognathosuchia is an extinct clade of neosuchian crocodyliforms that includes Goniopholididae and Pholidosauridae, two families of superficially crocodile-like aquatic crocodyliforms from the Mesozoic. Martin et al. (2014) named the clade after finding goniopholidids and pholidosaurids to group together in their phylogenetic analysis of crocodyliform evolutionary relationships. In their analysis, Pholidosauridae was monophyletic and Goniopholididae was paraphyletic, being an assemblage of successively more basal taxa within Coelognathosuchia. Coelognathosuchia itself was positioned near the base of the larger clade Neosuchia as the sister group to a clade containing the Early Cretaceous neosuchian Bernissartia and Eusuchia, the group that includes all modern crocodilians and their closest extinct relatives.Martin et al. named Coelognathosuchia from the Greek κοῖλος (koĩlos, "concave"), γνάθος (gnáthos, "jaw") and σοῦχος (soũchos, "crocodile"), after a small depression on the surface of the skull between the maxilla and jugal bones in both goniopholidids and pholidosaurs. Other diagonostic features of Coelognathosuchia include orbits (eye sockets) that are narrower than the frontal bone that separates them and smaller than the supratemporal fenestrae (two holes at the back of the skull roof) behind them, a notch between the premaxilla and maxilla at the tip of the snout, and the reduction or absence of the antorbital fenestrae (a pair of holes in the snout in front of each orbit).A close relationship between Goniopholididae and Pholidosauridae conflicts with the hypothesis that pholidosaurids are instead more closely related to the family Dyrosauridae. This alternate phylogeny was found in many analyses, including Jouve et al. (2006), Pol and Gasparini (2009), and de Andrade et al. (2011), who named the clade Tethysuchia. In both studies, Goniopholididae was found to be a more distantly related clade within Neosuchia. In their description of Pholidosaurus specimens from southwestern France, Martin and colleagues reiterated their opinion that Dyrosauridae is not as closely related to Pholidosauridae as stated by previous authors by pointing to numerous shared characters between the Cherves-de-Cognac pholidosaurid remains and Goniopholididae.Dolichobrachium
Dolichobrachium is a dubious genus of extinct poposaurid crurotarsan. Fossils have been found from the Popo Agie Formation in Wyoming and are of Late Triassic age. It was one of the first rauisuchians to have been named.Kayentasuchus
Kayentasuchus (meaning "Kayenta Formation crocodile") is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from a single skeleton found in rocks of the Sinemurian-Pliensbachian-age Lower Jurassic Kayenta Formation, northeastern Arizona.Kyasuchus
Kyasuchus is an extinct genus of shartegosuchid crocodylomorph. Fossils have been found from the Ilek Formation outcropping in the Kemerovo Oblast of Russia, deposited during the Aptian and Albian stages of the Early Cretaceous. The localities from which specimens of this genus have been found have also yielded many other vertebrate remains such as those of palaeonisciform fishes, turtles, various lizards, troodontids, triconodonts, the ceratopsian Psittacosaurus, and the protosuchian-grade crocodylomorph Tagarosuchus.Mesosuchia
"Mesosuchia" is an obsolete name for a group of terrestrial, semi-aquatic, or fully aquatic crocodylomorph reptiles. The marine crocodile Metriorhynchus had paddle-like forelimbs, Dakosaurus andiniensis had a skull that was adapted to eat large sea reptiles, and Shamosuchus was adapted for eating molluscs and gastropods. Shamosuchus also looked like modern crocodiles and was very closely related to their direct ancestor.
The "Mesosuchia" were formerly placed at Suborder rank as within Crocodylia. The "first" crocodiles were placed within their own suborder, Protosuchia; whilst extant species where placed within Suborder Eusuchia (meaning 'true crocodiles'). Mesosuchia were the crocodylians "in between". As it is a paraphyletic group however, it is not considered valid anymore. It is replaced by its phylogenetic equivalent Mesoeucrocodylia, which contains the taxa herein, the Crocodylia, and some allied forms more recently discovered.
The "Mesosuchia" was composed as:
Infraorder Thalattosuchia - Sea "Crocodiles"
Metasuchia is a major clade within the superorder Crocodylomorpha. It is split into two main groups, Notosuchia and Neosuchia. Notosuchia is an extinct group that contains primarily small-bodied Cretaceous taxa with heterodont dentition. Neosuchia includes the extant crocodylians and basal taxa, such as peirosaurids and pholidosaurids. It is phylogenetically defined by Sereno et al. (2001) as a clade containing Notosuchus terrestris, Crocodylus niloticus, and all descendants of their common ancestor.Paluxysuchus
Paluxysuchus is an extinct genus of neosuchian crocodyliform known from the Early Cretaceous Twin Mountains Formation (late Aptian stage) of north-central Texas. It contains a single species, Paluxysuchus newmani. Paluxysuchus is one of three crocodyliforms known from the Early Cretaceous of Texas, the others being Pachycheilosuchus and an unnamed species referred to as the "Glen Rose Form". Paluxysuchus has a long, flat skull that is probably transitional between the long and narrow skulls of many early neosuchians and the short and flat skulls of later neosuchians.Paralligatoridae
Paralligatoridae is an extinct family of neosuchian crocodyliforms that existed during the Jurassic and Cretaceous periods. It includes the genera Paralligator, Brillanceausuchus, Kansajsuchus, Shamosuchus, Scolomastax, Sabresuchus, Rugosuchus, Batrachomimus and Wannchampsus, as well as the yet-unnamed "Glen Rose form".Paratypothoracisini
Paratypothoracisini is a clade of aetosaurs within the subfamily Aetosaurinae. It is a node-based taxon that includes Heliocanthus, Paratypothorax, Tecovasuchus, and all descendants of their most recent common ancestor. All synapomorphies that diagnose the clade can be found in the osteoderms. These include dorsal eminences of the paramedian plates that never or almost never contact the posterior margins of the plates and dorsoventrally flattened "horns" formed from the lateral spikes of the cervical and anterior dorsal regions.Sebecia
Sebecia is an extinct clade of mesoeucrocodylian crocodyliforms that includes peirosaurids and sebecids. It was first constructed in 2007 to include Hamadasuchus, Peirosauridae, and Sebecus. It was initially considered to be the sister taxon of the clade Neosuchia, which includes living crocodilians, although some later studies have placed it within Neosuchia as a basal clade. Sebecians were terrestrial crocodyliforms characterized by their deep snouts and ziphodont dentition. They first appeared in the Late Cretaceous, survived the Cretaceous–Paleogene extinction event, and became extinct in the Miocene epoch.
According to paleontologists Hans Larsson and Hans-Dieter Sues, who constructed the clade in 2007, Sebecia also includes genera that were once assigned to Baurusuchidae, namely Pabwehshi. However, other baurusuchids, namely Baurusuchus, were placed outside Sebecia. Therefore, Baurusuchidae was considered polyphyletic and thus not a true clade. Below is the cladogram produced from Larsson and Sues' phylogenetic analysis:
Larsson and Sues defined Sebecidae as all taxa more closely related to Sebecus than to Peirosaurus or Uberabasuchus, both of which are peirosaurids. They defined Peirosauridae as all taxa more closely related to Peirosaurus and Uberabasuchus than to Sebecus, which is a sebecid. This definition is problematic, especially in relation to later phylogenetic studies of crocodyliforms. Many of these studies have found sebecids to be derived members of a clade containing notosuchians, while finding peirosaurids to be basal neosuchians. If the definitions of these two families are applied to later phylogenetic analyses, Sebecidae would include all notosuchians and Peirosauridae would include all neosuchians.Shartegosuchus
Shartegosuchus is a genus of protosuchian-grade crocodylomorph. It is known primarily from PIN 4174/2, the partial deformed skull and jaws of a juvenile. This specimen was discovered in ancient lake deposits of the Tithonian-age Upper Jurassic Tsagaantsav Formation, southwestern Mongolia. The estimated length of the holotype skull is 40 millimetres (1.6 in). This genus was similar to Nominosuchus, and both are assigned to the same family (Shartegosuchidae). Shartegosuchus was described in 1988 by Mikhail Efimov, and the type species is S. asperopalatum.Sichuanosuchus
Sichuanosuchus is an extinct genus of crocodylomorph from the Late Jurassic and possibly Early Cretaceous of China.Tethysuchia
Tethysuchia is an extinct clade of neosuchian mesoeucrocodylian crocodylomorphs from the late Middle Jurassic (Bathonian stage) to the Early Eocene (Ypresian stage) of Asia, Europe, North America and South America. It was named by the French paleontologist Eric Buffetaut in 1982 as a suborder. Tethysuchia was considered to be a synonym of Dyrosauridae or Pholidosauridae for many years. In most phylogenetic analyses the node Dyrosauridae+Pholidosauridae was strongly supported. De Andrade et al. (2011) suggested that Tethysuchia be resurrected for that node. They defined it as a node-based taxon "composed of Pholidosaurus purbeckensis (Mansel-Pleydell, 1888) and Dyrosaurus phosphaticus (Thomas, 1893), their common ancestor and all its descendants". In their analysis they found that the support for Tethysuchia is actually stronger than the support for Thalattosuchia. The following cladogram shows the position of Tethysuchia among the Neosuchia sensu this study.Williams Fork Formation
The Williams Fork Formation is a Campanian (Edmontonian) geologic formation of the Mesaverde Group in Colorado. Dinosaur remains are among the fossils, most notably Pentaceratops sternbergii, that have been recovered from the formation, although none have yet been referred to a specific genus. Other fossils found in the formation are ammonites, Neosuchia, and the mammal Meniscoessus collomensis.