Триасс кезеңінің тік денелі архозаврлары: Рауизухия тобының эволюциясы

Informal group of Triassic archosaurs with pillar erect posture
an explanation of very similar terms
Paraphyletic group
| name = "Rauisuchians"
| auto = yes
| taxon = Rauisuchia
| fossil range = Triassic, fossil range|249|200|latest=0|PS=Descendant taxon Crocodylomorpha survives to present; and possible early Jurassic presence. However, more recent studies on archosaur evolution have upended this idea based on phylogenetic analyses and cladistics, a modern approach to taxonomy based on clades (nested monophyletic groups of common ancestry). Since the early 2010s, archosaur classification schemes have stabilized on a system where Rauisuchia is rendered an evolutionary grade, or even a wastebin taxon. Crocodylomorphs most likely originated from a rauisuchian ancestor based on a myriad of shared traits, and some "rauisuchians" (such as Postosuchus and Rauisuchus) appear to be more closely related to crocodylomorphs than to other "rauisuchians" (such as Prestosuchus and Saurosuchus). This has been referred to as the pillar erect posture. "Rauisuchians" lived throughout most of the Triassic. Along with many other large archosaurs, the group died out in the Triassic Jurassic extinction event (barring crocodylomorphs, which survive to the present in the form of crocodilians). After their extinction, theropod dinosaurs were able to emerge as the sole large terrestrial predators, though there is still some debate over how the extinction influenced dinosaur evolution. The footprints of meat eating dinosaurs may have suddenly increased in size at the start of the Jurassic, when rauisuchians were absent. However, the apparent increase in dinosaur footprint size has instead been argued to be a result of increasing abundance of large theropods, rather than an abrupt acquisition of large size. Some "rauisuchians" may have existed in the very early Jurassic based on bone fragments from South Africa, but this identification is tentative. but it is now known that they are pseudosuchians. and Juul (1994) considered poposaurid rauisuchians to be more closely related to Crocodilia than to prestosuchids. Nesbitt (2003) presented a different phylogeny with a monophyletic Rauisuchia. The group may even be something of a "wastebasket taxon". Determining exact phylogenetic relationships is difficult because of the scrappy nature of a lot of the material. However, further discoveries and studies, such as a study on the braincase of Batrachotomus (2002) and restudies of other forms, such as Erpetosuchus (2002) have shed some light on the evolutionary relationships of this poorly known group.

Despite its inclusion as an informal grouping in numerous phylogenetic studies, "Rauisuchia" has never received a formal definition. Most analyses in the past decade have found "Rauisuchia" to be a paraphyletic grouping, including all studies with a large sample size. Those that found the possibility that it was a natural group produced only weak support for this hypothesis. This group includes Arizonasuchus, Lotosaurus, Sillosuchus, Shuvosaurus, and Effigia. One distinguishing feature of Group X is their lack of osteoderms, which are common among many other crurotarsans. Many more features are found in the pelvis, including fully fused sacral vertebrae and a long, thin crest on the ilium called the supra acetabular crest. Additionally, many members of Group X have smooth frontal and nasal bones, which make up the upper portion of the rostrum. In other "rauisuchians" and many other crurotarsans, this area has bumps and ridges. "Group X" is now termed Poposauroidea. In a more thorough test of archosaurian relationships published in 2011 by Sterling Nesbitt, "rauisuchians" were found to be paraphyletic, with Poposauroidea at the base of the clade Paracrocodylomorpha, and the rest of the "rauisuchians" forming a grade within the clade Loricata. Nesbitt noted that no previous study of "rauisuchian" relationships had ever included a wide variety of supposed "rauisuchians" as well as a large number of non "rauisuchian" taxa as controls.

Well known "rauisuchians" include Ticinosuchus of the Middle Triassic of Switzerland and Northern Italy, Saurosuchus of the Late Triassic (late Carnian) of Argentina, Prestosuchus of the Middle Late Triassic (late Ladinian early Carnian) of Brazil, and Postosuchus of the Late Triassic (Norian) of the southwest United States. The first "rauisuchian" known to paleontology was Teratosaurus, a German genus from the Late Triassic (Norian) of Germany. However, Teratosaurus was considered an early theropod dinosaur for much of its history, before it was demonstrated to be non dinosaurian in the 1980s. The concept of "rauisuchians" as a distinct group of reptiles distantly related to crocodiles was recognized by discoveries in Brazil in the 1940s (particularly Prestosuchus and Rauisuchus) and emphasized further by the description of Ticinosuchus in the 1960s. The oldest known "rauisuchians", in terms of geological age, are probably from the end of the Early Triassic (late Olenekian). Most of these early fossils are fragmentary and dubious remains from Russia, but some are better described and constrained, such as Xilousuchus, a ctenosauriscid from the Heshanggou Formation of China. Xilousuchus is neither the earliest branching archosaur nor "rauisuchian" despite its early age, and its presence in the Early Triassic suggests that other archosaur fossils are simply undiscovered from that time. The last known "rauisuchians", excluding their descendants the crocodylomorphs, are from the latter part of the Late Triassic. The shuvosaurid Effigia, from the "siltstone member" of the Chinle Formation in New Mexico, may be as young as the Rhaetian, the last stage of the Triassic. Effigia was recovered from the Coelophysis Quarry of Ghost Ranch. The same site also preserves a large undescribed archosaur, CM 73372, which seemingly represents a transitional form between "rauisuchians" and crocodylomorphs.

The following is a list of valid pseudosuchian genera which have been informally or formally classified as rauisuchians, as well as their modern cladistic interpretation. This list does not include genera named for dubious and poorly diagnosed "rauisuchian" material from Russia (Dongusia, Energosuchus, Jaikosuchus, Jushatyria, Scythosuchus, Tsylmosuchus, Vjushkovisaurus, Vytshegdosuchus) and China (Fenhosuchus, Wangisuchus), nor taxa reclassified as non "rauisuchian" archosaurs (Ornithosuchus, Gracilisuchus, Dongusuchus, Yarasuchus). GenusAuthorityYearLocationUnitAgeTraditional classificationModern classificationNotesImagesApatosuchusSues & Schoch2013Löwenstein Formation (Stubensandstein)NorianTheropodaLoricataA small "rauisuchian" based on a partial skull. Oiginally considered a species of Halticosaurus, a contemporary theropod dinosaur. ArganasuchusJalil & Peyer2007Timezgadiouine FormationCarnian?RauisuchidaeLoricataA "rauisuchian" based on scant skull and postcranial material similar to that of Batrachotomus, Luperosuchus, and Postosuchus. ArizonasaurusWelles1947Moenkopi FormationAnisianTheropoda? Rauisuchia?Poposauroidea (Ctenosauriscidae)One of the most complete ctenosauriscids, owing to a partial skeleton with skull and hip material discovered in 2002. Vital for understanding the affinities of ctenosauriscids with poposaurs. BatrachotomusGower1999Erfurt Formation (Lower Keuper)Late LadinianPrestosuchidae / RauisuchidaeLoricataOne of the most completely known "rauisuchians", with numerous fossils recovered from sites at Kupferzell, Crailsheim and Vellberg Eschenau. BromsgroveiaGalton1985Bromsgrove SandstoneAnisianTheropoda / Temnospondyli /PoposauridaePoposauroidea (Ctenosauriscidae)Named based on a distinctive poposaur like ilium, but also possibly incorporating "rauisuchian" fossil material such as teeth and vertebrae described from England since the mid 19th century. BystrowisuchusSennikov2012Lipovskaya Formation (Gamskian Gorizont)Late Olenekian?CtenosauriscidaePoposauroidea (Ctenosauriscidae)An early ctenosauriscid with low spined cervical (neck) vertebrae similar to Xilousuchus. CtenosauriscusKuhn1964Solling FormationLate Olenekian to Anisian? "Pelycosauria" / Temnospondyli / CtenosauriscidaePoposauroidea (Ctenosauriscidae)Known from slabs of sail backed dorsal vertebrae first discovered in 1871 and originally named as the (preoccupied) genus Ctenosaurus in 1902. Its affinities were strongly debated until stablizing as poposauroid archosaur upon the discovery of new Arizonasaurus and Lotosaurus fossils. DagasuchusLacerda et al.2015Middle Santa Maria Formation (Santacruzodon Assemblage Zone)Late Ladinian or early CarnianN/ALoricataA medium sized "rauisuchian" based on a hip bone which helps to fill a gap in the biostratigraphic record of Brazilian archosaurs. DecuriasuchusFrança2011Lower Santa Maria Formation (Dinodontosaurus Assemblage Zone)Late Ladinian or early CarnianPrestosuchidaeLoricataA medium sized "rauisuchian" named from 10 individuals (including several nearly complete skeletons) which died and fossilized together, suggesting a gregarious social structure. EffigiaNesbitt & Norell2006Chinle Formation ("siltstone member")Late Norian or RhaetianDerived SuchiaPoposauroidea (Shuvosauridae)A bizarre pseudosuchian convergent on ornithomimids, with a toothless skull, theropod like hip, and very short arms. Discovered within a sediment block collected from the Coelophysis Quarry of Ghost Ranch, New Mexico. EtjosuchusTolchard et al.2021Omingonde FormationLadinian or early CarnianErythrosuchidaeLoricataA large and possibly bipedal "rauisuchian" based on a partial skeleton previously misattributed to the erythrosuchid Erythrosuchus. FasolasuchusBonaparte1981Los Colorados FormationLate NorianRauisuchidaeLoricataOne of the last and largest "rauisuchians", occurring alongside an increasingly diverse fauna of sauropodomorph dinosaurs. HeptasuchusDawley et al.1979Popo Agie FormationLate Carnian?Prestosuchidae?LoricataOne of the oldest predatory archosaurs from North America, based on skull and postcranial fragments from Wyoming. Probably a close relative of Batrachotomus. HypselorhachisButler et al.2009Manda FormationAnisian? to Carnian?CtenosauriscidaePoposauroidea (Ctenosauriscidae)A ctenosauriscid based on a single well preserved vertebra with a very long neural spine. First mentioned in an unpublished 1966 by Alan Charig, but not formally described until 2009. LotosaurusZhang1975Badong FormationAnisian? to Carnian? "Lotosauridae"PoposauroideaAn unusual quadruped combining a neural spine sail with a toothless skull. Known from abundant fossils clustered into a bonebed, but most of these fossils remain undescribed. LuperosuchusRomer1971Chanares Formation (Tarjadia Assemblage Zone)Late Ladinian or earliest CarnianPrestosuchidaeLoricata
(Prestosuchidae? )A medium sized "rauisuchian" with a skull similar to Prestosuchus and Saurosuchus. MambawakaleButler et al.2022Manda FormationAnisian? to Carnian? "Pallisteriidae"Basal Paracrocodylomorpha?A possible paracrocodylomorph based on a massive partial skull. Mentioned as "Pallisteria angustimentum" in an unpublished 1967 manuscript by Alan Charig, but not formally described (and provided a new scientific name) until 2022. MandasuchusButler et al.2018Manda FormationAnisian? to Carnian?Prestosuchidae?Basal Paracrocodylomorpha?One of the most basal loricatans or poposauroids, first mentioned in a 1956 doctoral thesis by Alan Charig but not formally described until 2018. PolonosuchusBrusatte et al.2009Krasiejów claypitLate Carnian?RauisuchidaeLoricata (Rauisuchidae)A large rauisuchid, formerly named as a species of Teratosaurus and currently considered a close relative of Postosuchus. PoposaurusMehl1915Popo Agie Formation, Dockum Group, Chinle Formation (Monitor Butte Member, Blue Mesa Member, Sonsela Member)Late Carnian? to middle NorianDinosauria / PoposauridaePoposauroidea (Poposauridae)A widespread bipedal carnivore with hip bones so similar to dinosaurs that for decades it was mistaken as one. Though skull fragments are very rare, the postcrania is well described according to a nearly complete skeleton discovered in Utah in 2003. PostosuchusChatterjee1985Cooper Canyon Formation, Chatham Group?, Chinle Formation?NorianPoposauridae / RauisuchidaeLoricata (Rauisuchidae)A large rauisuchid with a short skull and possibly bipedal locomotion. One of the most well described and widespread "rauisuchians" from North America, though not all fossils referred to the genus may actually belong to it. Proposed as an ancestor to tyrannosaurids when first described. PrestosuchusHuene1942Lower Santa Maria Formation (Dinodontosaurus Assemblage Zone)Late Ladinian or early CarnianPrestosuchidaeLoricata (Prestosuchidae)Among the largest and most well described "rauisuchians", a quadrupedal form based on multiple partial skeletons. One massive well preserved skull has been named under the dubious genus "Karamuru vorax". ProcerosuchusHuene1938Lower Santa Maria Formation (Dinodontosaurus Assemblage Zone)Late Ladinian or early CarnianPrestosuchidaeLoricata (Prestosuchidae? )A poorly known taxon, possibly a synonym or species of Prestosuchus. QianosuchusLi et al.2006Guanling Formation (Panxian biota)AnisianIndeterminate CrurotarsiPoposauroideaA small, gracile archosaur, the only known "rauisuchians" with semiaquatic and piscivorous habits owing to its narrow skull and tall tail vertebrae. RauisuchusHuene1942Upper Santa Maria Formation (Hyperodapedon Assemblage Zone)Middle late CarnianRauisuchidaeLoricata (Rauisuchidae)The namesake of Rauisuchia. Known primarily from skull, vertebral, and hindlimb fossils, which reconstruct a stocky quadrupedal predator with a boxy skull full of serrated teeth. SaurosuchusReig1959Ischigualasto FormationLate CarnianPrestosuchidaeLoricata (Prestosuchidae? )A very large quadruped which lived alongside some of the earliest dinosaurs. Fossils include a well preserved cranium. ScolotosuchusSennikov2023Lipovskaya FormationLate OlenekianRauisuchidae"Rauisuchidae"A large rauisuchian based on distinctive vertebrae. ShuvosaurusChatterjee1993Cooper Canyon FormationEarly middle NorianTheropoda / "Chatterjeeidae"Poposauroidea (Shuvosauridae)An unusual beaked biped with two sets of fossils independently discovered in the mid 1990s: a toothless skull (Shuvosaurus) attributed to an ornithomimosaur like dinosaur, and postcranial material ("Chatterjeea") comparable to poposaurids. The synonymy between these two fossil sets would not be confirmed until the discovery of Effigia, a close relative. SillosuchusAlcober & Parrish1997Ischigualasto FormationLate CarnianPoposauridaePoposauroidea (Shuvosauridae)A probable relative of Effigia and Shuvosaurus based on its vertebrae and hip fossils. May have reached up to 10 meters (33 ft) in length according to a large isolated vertebra. StagonosuchusHuene1938Manda FormationAnisian? to Carnian?PrestosuchidaeLoricataA Tanzanian archosaur named from hip and vertebral fragments. May be a species of Prestosuchus. TeratosaurusMeyer1861Löwenstein Formation (Stubensandstein)NorianCarnosauria / Rauisuchidae / PoposauridaeLoricata (Rauisuchidae? )The earliest "rauisuchian" to be named, though its holotype fossil (a toothed maxilla bone) was misidentified as that of an early carnosaurian dinosaur. A complete re evaluation of archosaur systematics in the 1980s involved the recognition that Teratosaurus (and other "rauisuchians") were completely unrelated to carnosaurian dinosaurs. TicinosuchusKrebs1965,Mittlere GrenzbitumenzoneLate AnisianPrestosuchidaeSuchia (non paracrocodylomorph)Described from a flattened but complete skeleton from Monte San Giorgio on the Swiss Italian border. Its discovery established knowledge of "rauisuchian" proportions and their association with chirothere footprints. Commonly considered the sister taxon to Paracrocodylomorpha. TikisuchusChatterjee & Majumdar1987Tiki FormationCarnian?RauisuchidaeLoricata (Rauisuchidae? )A medium sized probable rauisuchid with a proportionally large skull. VivaronLessner et al.2016Chinle Formation (Petrified Forest Member)Middle NorianN/ALoricata (Rauisuchidae)Known from Postosuchus like skull and hip fragments from the Hayden Quarry at Ghost Ranch, New Mexico. Its discovery casts doubt on the assumption that all rauisuchid fossils from the southwestern United States can be referred to Postosuchus. XilousuchusWu1981Heshanggou FormationLate Olenekian or early AnisianProterosuchidae / ErythrosuchidaePoposauroidea (Ctenosauriscidae)One of the better understood early "rauisuchians", a ctenosauriscid including skull, braincase, and cervical (neck) fossils. YoungosuchusYoung1973Ermaying FormationAnisian?Erythrosuchidae /Rauisuchidae?LoricataBased on a well preserved but poorly described partial skeleton, including a skull. Originally named as a species of Vjushkovia, an erythrosuchid which has subsequently been synonymized with Garjainia.