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.
Archelon is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring 4.6 m (15 ft) from head to tail and 2.2–3.2 t in body mass. It is known only from the Pierre Shale and has one species, A. ischyros. In the past, the genus also contained A. marshii and A. copei, though these have been reassigned to Protostega and Kansastega, respectively. The genus was named in 1895 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family Protostegidae. The leatherback sea turtle was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle.
Stupendemys is an extinct genus of freshwater side-necked turtle, belonging to the family Podocnemididae. It is the largest freshwater turtle known to have existed, with a carapace over 2 meters long. Its fossils have been found in northern South America, in rocks dating from the Middle Miocene to the very start of the Pliocene, about 13 to 5 million years ago. Male specimens are known to have possessed bony horns growing from the front edges of the shell and the discovery of the fossil of a young adult shows that the carapace of these turtles flattens with age. A fossil skull described in 2021 indicates that Stupendemys was a generalist feeder.
Protostega is an extinct genus of sea turtle containing a single species, Protostega gigas. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas, time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation. Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of 3.9 metres (13 ft), it is the second-largest sea turtle that ever lived, second only to the giant Archelon, and one of the three largest turtle of all time along Archelon and Gigantatypus.
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
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.
Hutchemys is an extinct genus of softshell turtles from the late Cretaceous to the late Paleocene of New Mexico, Montana, Wyoming, Utah, and North Dakota, United States. It was first named by Walter G. Joyce, Ariel Revan, Tyler R. Lyson and Igor G. Danilov in 2009, and the type species is Hutchemys rememdium. H. rememdium is known from the holotype YPM PU 16795, which consists of a nearly complete postcranial skeleton, and from the referred specimen YPM PU 16781, found in the Ekalaka Member of the Fort Union Formation, Montana. Another referred specimen, YPM PU 14985, was found in the Cedar Point Quarry, Wyoming. The second species, H. arctochelys, is known from the holotype YPM PU 16319, a nearly complete carapace, and from the paratypes YPM PU 16320, YPM PU 16321, YPM PU 16322, YPM PU 16238. All specimens of H. arctochelys were recovered from the same quarry of the Tongue River Member, Fort Union Formation, near Burns Mine of Montana. A possible third species is represented by the unnamed specimen UCMP 130000 from the Paleocene Tullock Formation of Montana. Aspideretes? nassau (YPM PU 11566) from the Fort Union Formation, Duffy's Ranch of Sweet Grass County, Montana was also assigned to Hutchemys sp. A fourth species of Hutchemys, Hutchemys walkerorum, has been uncovered from the Hell Creek Formation of North Dakota. H. walkerorum is known from the holotype BDM 063, identified by the discovery and assembly of portions of its carapace. The fossil of H. walkerorum suggests that it was the only Hutchemys to live exclusively during the late Cretaceous era.
Carbonemys cofrinii is an extinct giant podocnemidid turtle known from the Middle Paleocene Cerrejón Formation of the Cesar-Ranchería Basin in northeastern Colombia. The formation is dated at around 60 to 57 million years ago, starting at about five million years after the KT extinction event.
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.
Tacuarembemys is an extinct genus of continental turtle from South America. It contains a single species, T. kusterae. The genus was described based on the external mold of a carapace and associated shell bone fragments found near the city of Tacuarembó, Uruguay. This fossil was found on the Tacuarembó Formation, whose estimated age ranges from late Jurassic to earliest Cretaceous.
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.
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.
Erquelinnesia is an extinct turtle genus from the Cretaceous period, which has been found in fossils. Paleontologist Louis Dollo first described this genus late 19th century from fossilized samples found in the layers of Upper Paleocene / Lower Eocene in Hainaut, Belgium. Erquelinnesia lived between the Upper Cretaceous and Lower Paleocene. Louis Dollo named his discovery as Pachyrhynchus gosseleti in 1886. However, in the following year, the nomenclature was changed by Dollo to Erquelinnesia gosseleti to resolve a conflict with another already existing generic name. Moreover, an additional species was attributed to the genus Erquelinnesia. The North American species called Erquelinnesia molaria that was known only from a fossilized mandible bone has subsequently re-categorized to the genus Euclastes.
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.
