The Cryptobranchidae are a family of large salamanders that are fully aquatic. The family includes some of the largest living amphibians. They are native to China, Japan, and the eastern United States. Giant salamanders constitute one of two living families—the other being the Asiatic salamanders belonging to the family Hynobiidae—within the Cryptobranchoidea, one of two main divisions of living salamanders.
Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South America. It is a large family of turtles with a significant fossil history dating back to the Cretaceous. The family is entirely Gondwanan in origin, with no members found outside Gondwana, either in the present day or as a fossil.
Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant ; and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.
Deinosuchus is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago (Ma), during the late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek deinos (δεινός), "terrible", and soukhos (σοῦχος), "crocodile". The first remains were discovered in North Carolina in the 1850s; the genus was named and described in 1909. Additional fragments were discovered in the 1940s and were later incorporated into an influential, though inaccurate, skull reconstruction at the American Museum of Natural History. Knowledge of Deinosuchus remains incomplete, but better cranial material found in recent years has expanded scientific understanding of this massive predator.
Hesperotestudo is an extinct genus of tortoise native to North and Central America from the Early Miocene to the Late Pleistocene. Species of Hesperotestudo varied widely in size, with a large undescribed specimen from the Late Pleistocene of El Salvador reaching 150 cm (4.9 ft) in carapace length, larger than that of extant giant tortoises. Historically considered a subgenus of Geochelone, it is now considered to be distantly related to that genus. Its relationships with other tortoises are uncertain. The exposed areas of the bodies of Hesperotestudo species were extensively covered with large dermal ossicles, which in life were covered in keratin. It has been suggested that species of Hesperotestudo were relatively tolerant of cold weather. Hesperotestudo became extinct at the end of the Pleistocene roughly co-incident with the arrival of the first humans in North America. There is apparently a site in Florida where one individual may have been killed that some suggested were evidence of butchering, although others suggested that the turtle was neither cooked nor does a ledge that was found near it date at the same time as it.
Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. E. hutchisoni, was named in 2003 but has since been reassigned to the genus Pacifichelys, while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.
Emarginachelys cretacea is a turtle belonging to the group Cryptodira, known from well preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana. Its exact phylogenetic position within Cryptodira is uncertain; different authors considered it to be either the earliest described chelydrid or a fossil relative of kinosternoids.
Pholidosauridae is an extinct family of aquatic neosuchian mesoeucrocodylian crocodylomorphs. Fossils have been found in Europe, Africa, North America and South America. The pholidosaurids first appeared in the fossil record during the Bathonian stage of the Middle Jurassic. Jouve & Jalil (2020) described postcranial material of a pholidosaurid from the Paleocene (Danian) of Ouled Abdoun Basin (Morocco), representing the most recent record of the family. The authors also reinterpreted putative Maastrichtian dyrosaurid Sabinosuchus as a pholidosaurid, and argued that at least two independent pholidosaurid lineages reached the Maastrichtian, among which one survived the Cretaceous–Paleogene extinction event. Before the publication of this study it was thought that the family became extinct during the Late Turonian stage of the Late Cretaceous.
Compsemys is an extinct genus of prehistoric turtles from the Late Cretaceous and Paleocene of North America and possibly Europe. The type species C. victa, first described by Joseph Leidy from the Hell Creek Formation in Montana in 1856, and another probable species C. russelli, described in 2012, from Paleocene deposits in France. Its affinites have long been uncertain, but it has recently been considered to be the most basal member of Paracryptodira, despite the clade first appearing in the Late Jurassic, and is sometimes included in its own family, Compsemydidae. A revision in 2020 found Compsemydidae to be more expansive, also containing Riodevemys and Selenemys from the Late Jurassic of Europe, and Peltochelys from the Early Cretaceous of Europe.
Trionyx is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today T. triunguis, the African or Nile softshell turtle, is the only extant softshell still classified as Trionyx. The other species still assigned to this genus are only known from fossils. T. triunguis is a relatively large, aquatic piscivore.
Baenidae is an extinct family of paracryptodiran turtles known from the Early Cretaceous to Eocene of North America. While during the Early Cretaceous they are found across North America, during the Late Cretaceous they are only found in Laramidia, having disappeared from Appalachia. The majority of lineages survived the K-Pg Extinction, but the family was extinct by the latest Eocene. The name of the type genus, Baena, appears to be of Native American origin. They are primarily found in freshwater deposits, and are considered to be aquatic, with a largely generalist habit.
Puentemys is an extinct genus of bothremydid turtle from the Paleocene-age Cerrejón Formation in Colombia. It is the largest known bothremydid, with a shell length of up to 1.51 m (5.0 ft). Puentemys is the only Paleocene bothremydid known from South America, and is most closely related to the genus Foxemys from the Late Cretaceous of Europe, showing that Bothremydini, the tribe of bothremydids to which Puentemys belonged, had a nearly worldwide distribution across the K-T boundary. The ancestors of Puentemys may have reached South America by dispersing across Paleocene coastlines or by riding currents across the Atlantic Ocean.
The Adocidae are an extinct family of aquatic and omnivorous turtles. They are freshwater cryptodiran turtles and are mainly known from Cretaceous and Paleogene Asia and North America.
Kallokibotion is an extinct genus of stem-turtle from the Upper Cretaceous, known from fossils found in Romania. One species is known, Kallokibotion bajazidi, which was named by Franz Nopcsa after his lover Bajazid Doda. It literally means 'beautiful box of Bajazid'; Nopcsa chose the name because, in the words of British palaeontologist Gareth Dyke, "the shape of the shell reminded him of Bajazid's arse". A second undescribed species is known from the Santonian of Hungary. Turtles similar to Kallokibotion were reported from the Paleocene of France and the Lower Maastrichtian of Volgograd Oblast, Russia, but these similarities were dismissed later.
Basilemys is a large, terrestrial nanhsiungchelyid turtle from the Upper Cretaceous of North and Central America. Basilemys has been found in rocks dating to the Campanian and Maastrichtian subdivisions of the Late Cretaceous and is considered to be the largest terrestrial turtle of its time. In an analysis made by Sukhanov et al. on a nansiunghelyid turtle from the Upper Cretaceous of Mongolia, it was demonstrated that Asian nanhsiungchelyids gave rise to the North American nanhsiungchelyids.
Nanhsiungchelyidae is an extinct family of land turtles known from Cretaceous deposits in Asia and North America. Nanhsiungchelyids were more terrestrial than many of their contemporaries, and may have gone extinct at the end of the Cretaceous as a result.
Anatolemys is an extinct turtle genus in the family Macrobaenidae. Two species are known, both of which lived in the Late Cretaceous. Fossils were discovered in the Yalovach Formation of Tajikistan, the Kulbikin Member and Khodzhakul and Bissekty Formations of Uzbekistan and the Bostobe Formation of Kazakhstan. With 70 cm (2.3 ft) in carapace length, Anatolemys maximus was one of the three largest macrobaenids along with Early Cretaceous Yakemys multiporcata and Paleocene Judithemys backmani.
Azabbaremys is an extinct genus of bothremydid pleurodiran turtle that was discovered in the Teberemt Formation of Mali. It was described in 2001, based on a skull that had been recovered in an expedition in 1981. The genus consists solely of the type species Azabbaremys moragjonesi. The genus name is derived from Azabbar, a monster in Tamasheq folk stories. The species is named for Morag Jones, a research student who participated in the discovery of the specimen and died in the expedition. Azabbaremys is most closely related to another Paleocene side-necked turtle, Acleistochelys.
Yakemys is an extinct genus of macrobaenid turtles from the Late Jurassic-Early Cretaceous (Tithonian-Valanginian?) lower Phu Kradung Formation of Thailand. It is monotypic, containing a single species, Yakemys multiporcata.
Acleistochelys is an extinct genus of large, bothremydid pleurodiran turtle known from Paleocene deposits in the Teberemt Formation of Mali. The type species, A. maliensis, was named for the country in which it was found. The holotype specimen consists of a nearly complete skull, shell fragments, pelvic fragments, and a cervical vertebra. It is most closely related to another Paleocene Malian side-necked turtle, Azabbaremys.
