The Atrato slider (''Trachemys medemi'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Emydidae Emydidae (Latin ''emys'' (freshwater tortoise) + Ancient Greek εἶδος (''eîdos'', “appearance, resemblance”)) is a family of testudines (turtles) that includes close to 50 species in 10 genera. Members of this family are commonly calle ...

endemic to northwestern

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. It was described in 2017.

Geographic range

The Atrato slider's geographical range is in the lower

Atrato river The Atrato River () is a river of northwestern Colombia. It rises in the slopes of the Western Cordillera and flows almost due north to the Gulf of Urabá (or Gulf of Darién), where it forms a large, swampy delta. Its course crosses the Cho ...

basin of Antioquia and Chocó departments of northwestern

, near the

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...

nian border.

Evolutionary history

There were two major migrations of sliders into South America during the

Great American Interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which lan ...

of the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

. During the first migration, which occurred about 7.1-8.6 million years ago, the last recent common ancestor of ''T. medemi'' and '' T. dorbigni'' spread from Central America into South America, with ''T. dorbigni'' expanding into the eastern parts of the continent while ''T. medemi'' remained in present-day Colombia. ''T. medemi'' diverged from ''T. dorbigni'' about 2.8-4.1 million years ago, with ''T. dorbigni'' diversifying about 1.9-2.3 million years ago. In the meantime, during the second migration of ''Trachemys'' sliders 2.2-2.5 million years ago, '' T. venusta'' arrived in South America.

References

{{DEFAULTSORT:Atrato Slider Trachemys Turtles of South America Endemic fauna of Colombia Reptiles of Colombia Reptiles described in 2017