Champsosaurus is an extinct genus of crocodile-like choristodere reptile, known from the Late Cretaceous and early Paleogene periods of North America and Europe (Campanian–Paleocene). The name Champsosaurus is thought to come from champsai, (χαμψαι) said in an Ancient Greek source to be an Egyptian word for "crocodiles", and sauros, (σαύρος) Greek for "lizard". The morphology of Champsosaurus resembles that of gharials, with a long, elongated snout. It was native to freshwater environments where it likely preyed on fish, similar to living gharials.
Choristodera is an extinct order of semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the Miocene. Choristoderes are morphologically diverse, with the best known members being the crocodile-like neochoristoderes such as Champsosaurus. Other choristoderans had lizard-like or long necked morphologies. Choristoderes appear to have been confined to the Northern Hemisphere, having been found in North America, Asia, and Europe, and possibly also North Africa. Choristoderes are generally thought to be derived neodiapsids that are close relatives or members of Sauria.
Simoedosaurus is an extinct reptile known from the Paleocene of North America, Europe and western Asia, and a member of the Choristodera, a group of aquatic reptiles that lived in the Northern Hemisphere from the Jurassic to the early Cenozoic.
Mekosuchus is a genus of extinct Australasian mekosuchine crocodilian. Species of Mekosuchus were generally small-sized, terrestrial animals with short, blunt-snouted heads and strong limbs. Four species are currently recognized, M. inexpectatus, M. whitehunterensis, M. sanderi and M. kalpokasi, all known primarily from fragmentary remains.
Mahajangasuchus is an extinct genus of crocodyliform which had blunt, conical teeth. The type species, M. insignis, lived during the Late Cretaceous; its fossils have been found in the Maevarano Formation in northern Madagascar. It was a fairly large predator, measuring up to 4 metres (13 ft) long.
Arambourgisuchus is an extinct genus of dyrosaurid crocodylomorph from the late Palaeocene of Morocco, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by palaeontologist Stéphane Jouve. Arambourgisuchus was a large animal with an elongated skull 1 meter in length.
Lazarussuchus is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and possibly Late Miocene deposits in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") from the late Oligocene of France. and L. dvoraki from the early Miocene of the Czech Republic. It was not a large animal; with the total preserved body and tail length of L. inexpectatus being just over 30 centimetres. A complete specimen of Lazarussuchus with preserved soft tissue was found from the Late Paleocene of France, but has not been assigned to a species.
Tchoiria () is a genus of neochoristoderan reptile from the Early Cretaceous of Mongolia. The name Tchoiria comes from the city of Choir which is nearby to where the holotype was found. Tchoiria is thought to have a similar diet to another neochoristoderan reptile, Champsosaurus, due to morphology of the skull. It would hunt in freshwater environments, like the living gharials, where it would prey on many different types of fish and turtles.
Neochoristodera is a lineage of specialised crocodile-like fully aquatic choristodere reptiles. Noted for their long jaws and large size, these animals were predominant across the Northern Hemisphere, occurring in freshwater and coastal environments across the Cretaceous and early Cenozoic.
Anthracosuchus is an extinct genus of dyrosaurid crocodyliform from the Paleocene of Colombia. Remains of Anthracosuchus balrogus, the only known species, come from the Cerrejón Formation in the Cerrejón mine, and include four fossil specimens with partial skulls. Anthracosuchus differs from other dyrosaurids in having an extremely short (brevirostrine) snout, widely spaced eye sockets with bony protuberances around them, and osteoderms that are smooth and thick. It is one of the most basal dyrosaurids along with Chenanisuchus and Cerrejonisuchus.
Knoetschkesuchus is a genus of small atoposaurid crocodylomorph from the Late Jurassic of Germany and Portugal. Two species are known: the German species K. langenbergensis, described by Schwarz and colleagues in 2017 based on two partial skeletons and various isolated bones; and the Portuguese species K. guimarotae, named from over 400 specimens including several partial skeletons. Knoetschkesuchus was a small and short-snouted crocodilian, measuring about 55 centimetres (22 in) in length, that primarily fed on small prey, including invertebrates, amphibians, and mammals. This specialization towards small prey ecologically separated Knoetschkesuchus from most of the other diverse crocodilians that it lived with in the island ecosystem of Jurassic Europe.
Kadimakara is an extinct genus of early archosauromorph reptile from the Arcadia Formation of Queensland, Australia. It was seemingly a very close relative of Prolacerta, a carnivorous reptile which possessed a moderately long neck. The generic name Kadimakara references prehistoric creatures from Aboriginal myths which may have been inspired by ice-age megafauna. The specific name K. australiensis relates to the fact that it was found in Australia. Prolacerta and Kadimakara were closely related to the Archosauriformes, a successful group which includes archosaurs such as crocodilians, pterosaurs, and dinosaurs.
Coeruleodraco is an extinct genus of choristoderan known from the Late Jurassic (Oxfordian) Tiaojishan Formation in China. Coeruleodraco is significant as the most complete Jurassic choristodere taxon, as the only other named Jurassic choristodere Cteniogenys is based on fragmentary remains. Although similar to Philydrosaurus in its proportions and postcranial characters, it is distinct in retaining several apparently plesiomorphic characters, including a short snout, paired external nares and an open lower temporal fenestra.
Rugarhynchos is an extinct genus of doswelliid archosauriform from the Late Triassic of New Mexico. The only known species is Rugarhynchos sixmilensis. It was originally described as a species of Doswellia in 2012, before receiving its own genus in 2020. Rugarhynchos was a close relative of Doswellia and shared several features with it, such as the absence of an infratemporal fenestra and heavily textured skull bones. However, it could also be distinguished by many unique characteristics, such as a thick diagonal ridge on the side of the snout, blunt spikes on its osteoderms, and a complex suture between the quadratojugal, squamosal, and jugal. Non-metric multidimensional scaling and tooth morphology suggest that Rugarhynchos had a general skull anatomy convergent with some crocodyliforms, spinosaurids, and phytosaurs. However, its snout was somewhat less elongated than those other reptiles.
Alligator hailensis, or Haile alligator, is a large, extinct species of Alligator known from the early Pleistocene of Florida. It is named after the town of Haile, Florida, where it was found. Its age and skeletal morphology is intermediate between the geologically older Alligator mefferdi and the modern American alligator, making it a transitional fossil.
Chinatichampsus is an extinct genus of crocodilian from the Devil's Graveyard Formation of Texas, specifically the Dalquest Desert Research Site. It is a monotypic genus, containing only the type species Chintanichampsus wilsonorum. A single specimen, TMM 45911–1, was first discovered in 2010. Chinatichampsus is the most basal Eocene caimanine, dating to between 42.8 and 41.5 million years ago, and is considered to be more basal than Protocaiman.
Ultrastenos is an extinct genus of Australian mekosuchine crocodilian that lived during the Late Oligocene in northwestern Queensland, Australia. Following its discovery, it was speculated that Ultrastenos was a slender-snouted animal similar to modern gharials or freshwater crocodiles due to the seemingly abruptly narrowing mandible. However, a later study found that this was a missinterpretation of the fossil specimen and that Ultrastenos instead had a more generalized lower jaw. The same publication also provided evidence that the fossils of Ultrastenos belonged to the same animal previously named "Baru" huberi, adding further evidence to the idea that the animal was short snouted, contrary to the initial hypothesis. Given that "Baru" huberi was named first, the type species of Ultrastenos changed from U. willisi to U. huberi in accordance with the rules of the ICZN. Ultrastenos was a small mekosuchine, measuring upwards of 1.5 m long.
Qianshanosuchus is a genus of basal crocodyloid from the Paleocene of the Qianshan Basin, China. The fossil material, which includes an incomplete skull and parts of the lower jaw, show various features usually associated with juvenile crocodiles alongside various unique traits that were used to erect a new genus. It is the first and only basal crocodyloid currently known from the Paleocene of China, which had previously only yielded alligatoroids and planocraniids. Its presence in this part of the world and its basal position to species of the genus Asiatosuchus supports the idea that crocodyloids dispersed from Asia into Europe. Qianshanosuchus only includes a single species, Qianshanosuchus youngi.
Eurycephalosuchus is an extinct genus of orientalosuchine alligatoroid from the Late Cretaceous Jiangxi Province of China. Known from a well preserved skull and mandible alongside various postcranial remains, Eurycephalosuchus possessed a short and broad skull with a very short skulltable. Eurycephalosuchus lived with at least one other crocodilian, an indetermined member of the clade Brevirostres. The genus is monotypic, containing only the species Eurycephalosuchus gannanensis.
Varanosuchus is an extinct genus of atoposaurid neosuchian from the Early Cretaceous Sao Khua Formation of Thailand. Varanosuchus is known from three individuals which preserve assorted postcranial material and a complete skull. The skull of Varanosuchus was altirostral, meaning it wasn't flattened like in modern crocodilians and instead much deeper, while the limbs were slender and straight, leading to it somewhat resembling a monitor lizard. Little is known about the ecology of atoposaurids, however, based on the slender, erect limbs, the altirostral skull and the well ornamented osteoderms it has been suggested that Varanosuchus was a terrestrial animal with some semi-aquatic affinities. Only a single species is recognized, Varanosuchus sakonnakhonensis.
