The Madagascan big-headed turtle (''Erymnochelys madagascariensis'') is a
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 t ...
native to the waters of permanent slow moving
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of w ...
s and
lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s in western
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
. These turtles are critically endangered and have been evaluated to be the most endangered turtle in the world by a 2018 review. Due to its ancient origins and threatened status, it is ranked as #1 on the
EDGE of Existence programme
The ''EDGE of Existence programme'' is a research and conservation initiative that focuses on species deemed to be the world’s most "Evolutionarily Distinct and Globally Endangered" (EDGE). Developed by the Zoological Society of London (ZSL), the ...
's list of priority reptiles.
Taxonomy
It is a highly evolutionary distinctive species, the only member of the ancient family Podocnemidae found outside of
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. It diverged from its closest living relative, ''
Podocnemis
''Podocnemis'' is a genus of aquatic turtles, commonly known as South American river turtles, in the family Podocnemididae. The genus consists of six extant species occurring in tropical South America.
'', during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
, about 78 million years ago. Fossils of podocnemid turtles that are suggested to be closely related to ''Erymnochelys'' belonging to the same tribe Erymnochelyini, are known from the Cenozoic of Africa and Europe, with the youngest remains of turtles belonging to Erymnochelyini in mainland Africa dating to the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58backwaters and lakes. Many of the hatching and juvenile turtles move into smaller rivers, where they can grow quickly and safely before going into deeper and larger bodies of water.
Range
It can be found in the western lowland areas of Madagascar.
Threats
The main threat for this species is that they are heavily exploited for food, caught in nets, fish traps and by hooks and
lines
Line most often refers to:
* Line (geometry), object with zero thickness and curvature that stretches to infinity
* Telephone line, a single-user circuit on a telephone communication system
Line, lines, The Line, or LINE may also refer to:
Arts ...
. It is also hunted for illegal export to
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
for the traditional medicinal market. Another threat is land development as it destroys its natural habitat.
Despite their vulnerability to extinction, they are commonly eaten for food and they are still commonly shipped from Madagascar to Asia to help meet the demand of Asia's traditional medicine market. A captive breeding program has also been started to prevent the species from becoming extinct. The Turtle Conservation Fund (TCF) intends to raise US$5.6 million to cover a five-year 'Global Action Plan' which includes captive breeding and reintroduction projects, trade monitoring, new rescue centers, local conservation plans, and educational programs.