''Chelus orinocensis'', the Orinoco mata mata, is a species of freshwater

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

found in northern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

in the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

, upper Rio Negro– Branco and Essequibo basins, and in

Trinidad Trinidad is the larger, more populous island of the Republic of Trinidad and Tobago, the country. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is the southernmost island in ...

. It was split off from the very similar '' Chelus fimbriata'' in 2020.

Taxonomy

A genetic analysis of the

mata mata Matamata () is a town in Waikato, New Zealand. It is located near the base of the Kaimai Ranges, and is a thriving farming area known for Thoroughbred horse breeding and training pursuits. It is part of the Matamata-Piako District, which tak ...

was reported in 2020, which showed a deep split between two of its populations. The authors proposed that the mostly Orinoco population be assigned to a new species, ''Chelus orinocensis'', with the Amazon population retaining the '' Chelus fimbriatus'' species designation. However, ''Chelus fimbriatus'' is absent from the upper Rio Negro–Branco system (the northernmost part of the Amazon basin), which instead is inhabited by ''Chelus orinocensis''. Prior to its description as a separate species, observations of distinctive morphological differences had already been noted among specimens in the populations of the Amazon and Orinoco basins.

References

{{Taxonbar, from1=Q92600465 Chelus Turtles of Brazil Reptiles of Colombia Reptiles of Guyana Reptiles of Trinidad and Tobago Reptiles of Venezuela Reptiles described in 2020 Extant Pliocene first appearances