| Chelus Temporal range: | |
|---|---|
 | |
| Chelus fimbriatus | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Pleurodira |
| Family: | Chelidae |
| Subfamily: | Chelinae |
| Genus: | Chelus Duméril, 1805 [2] |
Chelus is a genus of large freshwater turtles found in tropical South America. Formerly considered to be a monotypic genus, [3] it now consists of two extant species after Chelus orinocensis was identified in 2020 from a genetic analysis. [4]
Fossils of the extinct † C. colombianus have been found in Venezuela, Colombia, and Brazil, including a skull dating to the early Miocene (~ 16 m.y.) of the Castilletes Formation, Cocinetas Basin, in Colombia. The fossil shows that the skull morphology of Chelus has been almost unchanged since the Miocene. [5] [6]
There are two extant recognized species in this genus [3] [7] and one extinct species: [1]
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.
The mata mata, mata-mata, or matamata is a South American species of freshwater turtle found in the Amazon basin and river system of the eastern Guianas. It was formerly believed to also occur in the Orinoco basin, western Guianas and upper Rio Negro–Branco system, but in 2020 these populations were found to belong to a separate species, Chelus orinocensis. Subsequently, some authorities have modified the common name of Chelus fimbriata to Amazon mata mata. These two are the only extant species in the genus Chelus.
The giant Asian pond turtle inhabits rivers, streams, marshes, and rice paddies from estuarine lowlands to moderate altitudes throughout Cambodia and Vietnam and in parts of Laos, Malaysia, Myanmar and Thailand.
Emys is a small genus within the family Emydidae. The genus, consisting primarily of freshwater pond turtles, is endemic to Europe. It is the only genus in the Emydidae outside of North America.
Chelodina, collectively known as snake-necked turtles, is a large and diverse genus of long-necked chelid turtles with a complicated nomenclatural history. Although in the past, Macrochelodina and Macrodiremys have been considered separate genera and prior to that all the same, they are now considered subgenera of the Chelodina, further Macrochelodina and Macrodiremys are now known to apply to the same species, hence Chelydera is used for the northern snake-necked turtles.
Macrochelys is a genus of very large freshwater turtles in the family Chelydridae, native to the Southeastern and Midwestern United States. Only a single extant species was recognized until 2014, when a study divided it into two or possibly three species. These turtles are easily recognized by three distinct dorsal ridges with raised spikes.
Kinosternon is a genus of small aquatic turtles from the Americas known commonly as mud turtles.
The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. The division between these two suborders represents a very deep evolutionary divide between two very different types of turtles. The physical differences between them, although anatomical and largely internal, are nonetheless significant, and the zoogeographic implications of them are substantial. The Pleurodira are known more commonly as the side-necked turtles and the name Pleurodira quite literally translates to side neck, whereas the Cryptodira are known as hidden-necked turtles. The Pleurodira turtles are currently restricted to freshwater habitats in the Southern Hemisphere, largely to Australia, South America, and Africa. Within the Pleurodira, three living families are represented: Chelidae, also known as the Austro-South American side-necked turtles, the Pelomedusidae, also known as the African mud terrapins, and the Podocnemididae, also known as the American side-neck river turtles. However, they were cosmopolitan clade during the Cretaceous and most of the Cenozoic, and even occurred in marine environments around the world.
Cyclanorbis is a genus of softshell turtles in the family Trionychidae. The genus is endemic to Africa.
Cycloderma is a genus of softshell turtles in the subfamily Cyclanorbinae of the family Trionychidae. The genus is endemic to Africa.
The Namoi River snapping turtle, also commonly known as Bell's turtle, the Namoi River elseya, or Bell's saw-shelled turtle, is a species of turtle in the family Chelidae. The species is endemic to New South Wales, Australia.
Elseya is a genus of large side-necked turtles, commonly known as Australian snapping turtles, in the family Chelidae. Species in the genus Elseya are found in river systems in northern and northeastern Australia and throughout the river systems of New Guinea. They are identified by the presence of alveolar ridges on the triturating surfaces of the mouth and the presence of a complex bridge strut.
The Western New Guinea stream turtle or New Guinea snapping turtle is a species of freshwater turtle in the Chelidae family. It is found in the Bird's Head Peninsula and the Bomberai Peninsula west of Cenderawasih Bay, and on the island of Waigeo of West Papua, Indonesia.
Sometimes called the bearded toadheads but better known by their scientific name of Phrynops this genus of turtles has often been a bit of a dumping ground for the short-necked South American turtles of the family Chelidae.
Rhinoclemmys is a genus of turtles in the family Geoemydidae, the only genus in the subfamily Rhinoclemmydinae. Member species of the genus are commonly known as the Neotropical wood turtles and are the only geoemydids known from the Americas. As such, they have adapted to a wide range of habitats, which is reflected in the species' common names.
The Myuchelys is a genus of turtles, the Australian saw-shelled turtles, in the family Chelidae and subfamily Chelodininae. They inhabit the headwaters and tributaries of rivers within their range and this led to the name Myuchelys, which is formed from the Aboriginal word myuna meaning clear water and the Greek chelys meaning turtle. They have a short neck and the intergular scute completely separates the gular scutes. They have no alveolar ridge separating them from the snapping turtles of the genus Elseya.
Mesoclemmys is a genus of South American turtles in the family Chelidae.
Elseya schultzei, commonly known as Schultze's snapping turtle, is a species of chelid turtle endemic to northern New Guinea.
Megalochelys is an extinct genus of tortoises that lived from the Miocene to Pleistocene. They are noted for their giant size, the largest known for any tortoise, with a maximum carapace length of over 2 m (6.5 ft) in M. atlas. The genus ranged from western India and Pakistan to as far east as Sulawesi and Timor in Indonesia, though the island specimens likely represent distinct species.
Chelus orinocensis, the Orinoco mata mata, is a species of freshwater turtle found in northern South America in the Orinoco, upper Rio Negro–Branco and Essequibo basins, and in Trinidad. It was split off from the very similar Chelus fimbriata in 2020.
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