The Madagascan big-headed turtle (''Erymnochelys madagascariensis'') is a
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 ...
native to the waters of permanent slow moving
river
A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...
s and
lake
A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...
s in western
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
. These turtles are
critically endangered
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
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'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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. 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 (biology), family Podocnemididae. The genus consists of six Extant taxon, extant species occurring in tropical South America.Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...
, 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 (geology), epoch in the geologic time scale that extends from 5.33 to 2.58podocnemidid, the
big-headed Amazon River turtle
The Big-headed Amazon River turtle (''Peltocephalus dumerilianus''),Podocnemis
''Podocnemis'' is a genus of aquatic turtles, commonly known as South American river turtles, in the Family (biology), family Podocnemididae. The genus consists of six Extant taxon, extant species occurring in tropical South America.backwaters 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. It is also hunted for illegal export to
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
for the traditional medicinal market. Another threat is
land development
Land development is the alteration of landscape in any number of ways, such as:
* Changing landforms from a natural or semi-natural state for a purpose such as agriculture or House, housing
* subdivision (land), Subdividing real estate into Lot ( ...
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
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
. 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.