Elachistosuchus is an extinct genus of neodiapsid reptile, most likely basal archosauromorph, known from the Late Triassic Arnstadt Formation of Saxony-Anhalt, central Germany. It contains a single species, Elachistosuchus huenei, known from a single individual E. huenei, originally considered a pseudosuchian archosaur and then a rhynchocephalian lepidosaur, was largely ignored in the scientific literature, as its small size and fragility did not permit further mechanical preparation and examination. More recently however, a non-invasive μCT scanning was performed to resolve its placement within Reptilia, and found it to represent a more basal reptile, potentially closely related to several early archosauromorph clades.
Proterosuchus is an extinct genus of archosauriform reptiles that lived during the Early Triassic. It contains three valid species: the type species P. fergusi and the referred species P. alexanderi and P. goweri. All three species lived in what is now South Africa. The genus was named in 1903 by the South African paleontologist Robert Broom. The genus Chasmatosaurus is a junior synonym of Proterosuchus.
Doswellia is an extinct genus of archosauriform from the Late Triassic of North America. It is the most notable member of the family Doswelliidae, related to the proterochampsids. Doswellia was a low and heavily built carnivore which lived during the Carnian stage of the Late Triassic. It possesses many unusual features including a wide, flattened head with narrow jaws and a box-like rib cage surrounded by many rows of bony plates. The type species Doswellia kaltenbachi was named in 1980 from fossils found within the Vinita member of the Doswell Formation in Virginia. The formation, which is found in the Taylorsville Basin, is part of the larger Newark Supergroup. Doswellia is named after Doswell, the town from which much of the taxon's remains have been found. A second species, D. sixmilensis, was described in 2012 from the Bluewater Creek Formation of the Chinle Group in New Mexico; however, this species was subsequently transferred to a separate doswelliid genus, Rugarhynchos. Bonafide Doswellia kaltenbachi fossils are also known from the Chinle Formation of Arizona.
Tasmaniosaurus is an extinct genus of archosauromorph reptile known from the Knocklofty Formation of West Hobart, Tasmania, Australia. The type species is T. triassicus. This genus is notable not only due to being one of the most complete Australian Triassic reptiles known, but also due to being a very close relative of Archosauriformes. Once believed to be a proterosuchid, this taxon is now believed to have been intermediate between advanced non-archosauriform archosauromorphs such as Prolacerta, and basal archosauriforms such as Proterosuchus. Features traditionally used to define Archosauria and later Archosauriformes, such as the presence of an antorbital fenestra and serrated teeth, are now known to have evolved prior to those groups due to their presence in Tasmaniosaurus.
Kalisuchus was a genus of basal archosauriform known from remains unearthed from the Arcadia Formation of the Early Triassic of the Crater, Southwest of Rolleston, south central Queensland, Australia. It was named after Kali, the Hindu goddess of destruction, a reference to the very fragmentary nature of its remains. The type species of Kalisuchus is K. rewanensis, which refers to the Rewan Group. The Arcadia formation is dated to the Induan age at the very beginning of the Triassic, making Kalisuchus one of the oldest archosauromorphs known in Australia.
Proterochampsidae is a family of proterochampsian archosauriforms. Proterochampsids may have filled an ecological niche similar to modern crocodiles, and had a general crocodile-like appearance. They lived in what is now South America in the Middle and Late Triassic.
Malerisaurus is an extinct genus of archosauromorph known from Telangana of India and Texas of the USA.
Archosaurus is an extinct genus of carnivorous proterosuchid archosauriform reptile. Its fossils are dated to the latest Permian of Russia and Poland, it is one of the earliest known archosauriforms. The type and only species is Archosaurus rossicus, known from several fragmentary specimens which cumulatively represent parts of the skull and cervical vertebrae. It would have been 3 metres (9.8 ft) long when fully grown.
Fugusuchus is an extinct genus of archosauriform, probably the basal-most member of the family Erythrosuchidae. The genus is known from a single fossil from the middle Early Triassic Heshanggou Formation in Shanxi, China. The partial skeleton consists of an incomplete skull, parts of the right forelimb, and an intercentrum. The skeleton, known as GMB V 313, is currently in the Geological Museum of China in Beijing.
Yonghesuchus is an extinct genus of Late Triassic archosaur reptile. Remains have been found from the early Late Triassic Tongchuan Formation in Shanxi, China. It is named after Yonghe County, the county where fossils were found. Currently only one species, Y. sangbiensis, is known. The specific name refers to Sangbi Creek, as fossils were found in one of its banks.
Tsylmosuchus is an extinct genus of proterosuchid archosauriform reptile known from Western Russia. Fossils referred to Tsylmosuchus occurred over a wide area in sediments corresponding to the Induan and Olenekian stages of the Early Triassic. Most of these fossils are fragmentary neck vertebrae which were originally reported as sharing similarities with crocodile-line archosaurs (pseudosuchians) such as Mandasuchus. As a result, Tsylmosuchus was first described as part of the family Rauisuchidae, making it supposedly one of the oldest known archosaurs. However, its fragmentary remains do not show any of the distinguishing features of rauisuchids or even pseudosuchians in general, so Tsylmosuchus has more recently been interpreted as an indeterminate archosauriform. Although three species of Tsylmosuchus have been named, they lack diagnostic traits and are probably not distinct from each other. In 2023, Tsylmosuchus was reinterpreted as a proterosuchid, specifically a member of the subfamily Chasmatosuchinae.
Koilamasuchus is an extinct genus of indeterminate archosauriform from the Triassic of Argentina. It is based on an external mold of a partial postcranial skeleton from the Quebrada de los Fósiles Formation. Due to its incomplete nature, the relationships of this reptile are difficult to establish. Originally described as a non-archosaur archosauriform, later studies tentatively considered it a doswelliid or a suchian archosaur.
Doswelliidae is an extinct family of carnivorous archosauriform reptiles that lived in North America and Europe during the Middle to Late Triassic period. Long represented solely by the heavily-armored reptile Doswellia, the family's composition has expanded since 2011, although two supposed South American doswelliids were later redescribed as erpetosuchids. Doswelliids were not true archosaurs, but they were close relatives and some studies have considered them among the most derived non-archosaurian archosauriforms. They may have also been related to the Proterochampsidae, a South American family of crocodile-like archosauriforms.
Protorosauria is an extinct, likely paraphyletic group of basal archosauromorph reptiles from the latest Middle Permian to the end of the Late Triassic of Asia, Europe and North America. It was named by the English anatomist and paleontologist Thomas Henry Huxley in 1871 as an order, originally to solely contain Protorosaurus. Other names which were once considered equivalent to Protorosauria include Prolacertiformes and Prolacertilia.
Prolacerta is a genus of archosauromorph from the lower Triassic of South Africa and Antarctica. The only known species is Prolacerta broomi. The generic name Prolacerta is derived from Latin meaning “before lizard” and its species name broomi is in commemoration of the famous paleontologist Robert Broom, who discovered and studied many of the fossils found in rocks of the Karoo Supergroup. When first discovered, Prolacerta was considered to be ancestral to modern lizards, scientifically known as lacertilians. However, a study by Gow (1975) instead found that it shared more similarities with the lineage that would lead to archosaurs such as crocodilians and dinosaurs. Prolacerta is considered by modern paleontologists to be among the closest relatives of the Archosauriformes.
Eorasaurus is an extinct genus of archosauromorph reptile known from the middle Late Permian of Tatarstan, European Russia. It contains a single species, Eorasaurus olsoni. When originally described by Sennikov (1997), Eorasaurus was identified as an early archosauromorph and assigned to the family Protorosauridae, Ezcurra et al. (2014) and Ezcurra (2016) later reclassified Eorasaurus and placed it within the group Archosauriformes. Eorasaurus is based solely on scant fossil material from the neck region, and is thus considered an unstable taxon in phylogenetic analyses. If Eorasaurus is an archosauriform, it would be the oldest known member of the group and would pre-date the previous record holder.
Asperoris is an extinct genus of archosauriform reptile known from the Middle Triassic Manda Beds of southwestern Tanzania. It is the first archosauriform known from the Manda Beds that is not an archosaur. However, its relationships with other non-archosaurian archosauriforms are uncertain. It was first named by Sterling J. Nesbitt, Richard J. Butler and David J. Gower in 2013 and the type species is Asperoris mnyama. Asperoris means "rough face" in Latin, referring to the distinctive rough texture of its skull bones.
Aenigmastropheus is an extinct genus of early archosauromorph reptiles known from the middle Late Permian Usili Formation of Songea District, southern Tanzania. It contains a single species, Aenigmastropheus parringtoni, known solely from UMZC T836, a partial postcranial skeleton of a mature individual. It was collected in 1933, and first described in 1956, as a "problematic reptile" due to its unique morphology. Therefore, a binomial name was erected for this specimen in 2014. Aenigmastropheus was probably fully terrestrial.
Polymorphodon is an extinct genus of archosauriform reptile from the Middle Triassic of Germany. The only known species is Polymorphodon adorfi, discovered in Lower Keuper deposits at a quarry in Eschenau, Germany. Polymorphodon is notable for its heterodont dentition, with long and conical premaxillary teeth followed by thin maxillary teeth with large serrations. Maxillary teeth near the back of the mouth are short and leaf-shaped, similar to some living and extinct reptiles with a herbivorous or omnivorous diet. This may suggest that Polymorphodon had some reliance on plants in its diet, a rarity among basal archosauriforms, most of which are carnivores.
Oryctorhynchus is an extinct genus of rhynchosaur from the Late Triassic (Carnian-Norian)-aged Wolfville Formation of Nova Scotia, Canada that may have been the same animal as Beesiiwo. The type species, O. bairdi, was named and described in 2020. It was originally seen as a species of Hyperodapedon until 2020.
