Quinkana is an extinct genus of mekosuchine crocodylians that lived in Australia from about 25 million to about 10,000 years ago, with the majority of fossils having been found in Queensland. Four species are currently recognized, all of which have been named between 1981 and 1997. The two best understood species are Q. fortirostrum, the type species, and Q. timara, a more gracile form from the Miocene. The other two species, Q. babarra and Q. meboldi, from the Pliocene and Oligocene respectively, are only known from a few poorly preserved bone fragments. The name Quinkana comes from the "Quinkans", a legendary folk spirit from Gugu-Yalanji mythology.
Australosuchus is an extinct monospecific genus of crocodylian belonging to the subfamily Mekosuchinae. The type and only known species Australosuchus clarkae lived during the Late Oligocene and the Early Miocene in the Lake Eyre Basin of South Australia. It was described in 1991 by Paul Willis and Ralph Molnar from fossil material discovered at Lake Palankarinna.
Ceratosuchus is an extinct genus of alligatorine crocodylian from latest Paleocene rocks of Colorado's Piceance Basin and earliest Eocene rocks of Wyoming's Bighorn Basin in North America, a slice of time known as the Clarkforkian North American Land Mammal Age. Like its modern relatives, Ceratosuchus was a swamp-dwelling predator. It is named for the pair of flattened, triangular bony plates that extend from the back of its head.
Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine, with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event.
Wannaganosuchus is an extinct genus of small alligatorid crocodilian. It was found in Late Paleocene-age rocks of Billings County, North Dakota, United States.
Harpacochampsa is a poorly known Early Miocene crocodilian from the Bullock Creek lagerstätte of the Northern Territory, Australia. The current specimen consists of a partial skull and fragments of a long, slender snout reminiscent of that of a false gharial, demonstrating that it was a piscivore in life.
Labidosaurikos is a genus of extinct captorhinid tetrapods that lived around 279 to 272 million years ago during Kungurian age of the lower Permian. The American paleontologist John Willis Stovall first described Labidosaurikos in 1950, naming it "Labidosaurus like" for the striking similarity of the holotype skull of his specimen to the cranial anatomy of another captorhinid Labidosaurus hamatus.
Chrysochampsa is an extinct monospecific genus of caiman of the clade Brachychampsini. Fossils have been found from the Golden Valley Formation of North Dakota and date back to the Wasatchian regional North American faunal stage of the early Eocene. During this time North Dakota experienced the Early Eocene Climatic Optimum, creating lush forests, swamps and meandering rivers that were the home to at least four distinct crocodilians. Unlike the contemporary Ahdeskatanka, which was a small animal with crushing teeth, Chrysochampsa would have been a generalist and due to its size and lack of significant mammalian carnivores the apex predator of the region. The genus had been proposed to be synonymous with Allognathosuchus in 2004s, but this claim has since then been repeatedly refuted. A 2024 study has recovered it as an early branching member of the Caimaninae, forming a clade with Cretaceous forms such as Brachychampsa. Chrysochampsa is a monotypic genus, containing only the type species, Chrysochampsa mlynarskii.
Euthecodon is an extinct genus of long-snouted crocodile. It was common throughout much of Africa during the Neogene, with fossils being especially common in Kenya, Ethiopia, and Libya. Although superficially resembling that of gharials, the long snout was a trait developed independently from that of other crocodilians and suggests a diet of primarily fish. Euthecodon coexisted with a wide range of other crocodiles in the areas it inhabited before eventually going extinct during the Pleistocene.
Xixiasaurus is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull, part of the lower jaw, and teeth, as well as a partial right forelimb.
Astorgosuchus is an extinct monospecific genus of crocodilian, closely related to true crocodiles, that lived in Pakistan during the late Oligocene period. This crocodile may have reached lengths of up to 7–8 m (23–26 ft) and is known to have preyed on many of the large mammals found in its environment. Bite marks of a large crocodile have been found on the bones of juvenile Paraceratherium, however if these were left by Astorgosuchus cannot be said with certainty. The genus contains a single species, Astorgosuchus bugtiensis, which was originally named as a species of Crocodylus in 1908 and was moved to its own genus in 2019.
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.
Kalthifrons is an extinct monospecific genus of mekosuchine crocodylian known from the Pliocene Tirari Formation of Australia. More specifically, Kalthifrons was recovered from the Mampuwordu Sand Member, which underlies the younger sediments of the Pompapillina Member. This is significant, as the latter preserves some of the earliest records of the genus Crocodylus in Australia, which would eventually go on to replace mekosuchines. It is currently unclear whether or not the Tirari Crocodylus directly outcompeted Kalthifrons or simply moved into the region after the niche was left empty by the extinction of the local mekosuchines. Should the later be the case, then Kalthifrons may have simply been the victim of global cooling and aridification. A point in favour of the competition hypothesis is that both Kalthifrons and the Tirari Crocodylus have broadly similar skull forms, with both being interpreted as generalist semi-aquatic predators much like many of today's crocodiles. Though far from large, Kalthifrons was nonetheless bigger than many other mekosuchines such as Trilophosuchus and Mekosuchus. The genus is monotypic, meaning it contains only a single species, Kalthifrons aurivellensis.
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.
Alligator munensis is an extinct species of alligator from the Quaternary of Thailand. After the skull of A. munensis was discovered, it was tentatively assigned to the Chinese alligator before being recognized as a distinct species. Although the two are still considered to be close relatives, the pronounced anatomical differences suggest that the two species split from one another long prior to the Pleistocene, possibly during the uplifting of the Tibetan Plateau during the Miocene. It had a short and robust skull and may have had globular back teeth possibly corresponding to a greater amount of hard-shelled prey items. The nostrils of A. munensis were positioned much further towards the back of the skull than in other alligators, but the function of this is unknown.
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.
Epoidesuchus is an extinct pepesuchine peirosaurid from the Late Cretaceous Adamantina Formation of Brazil. Like other members of the Pepesuchinae and unlike the closely related members of Peirosaurinae, Epoidesuchus had long and gracile jaws, which may indicate that they were semi-aquatic animals more similar to modern crocodilians. The genus is monotypic, meaning it only contains a single species, Epoidesuchus tavaresae.
Sutekhsuchus is a species of gavialine crocodilian from the Miocene of Libya and Egypt. While this species was originally described as a species of the genus Tomistoma, which includes the modern false gharial, later studies have shown that it was actually a much more derived gavialoid closely related to the Kenyan Eogavialis andrewsi. Since it initially "deceived" paleontologists, it was named for the Egyptian god of deception Sutekh. It once inhabited the slow-moving rivers, estuaries and lagoons of what is now Gebel Zelten and Wadi Moghra, environments it shared with a variety of other crocodilians including the narrow-snouted Euthecodon and the robust Rimasuchus. Only a single species is currently assigned to Sutekhsuchus, the type species S. dowsoni.
