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Madagascan big-headed turtle

Madagascan big-headed turtle
Photographed at Berenty Reserve
CITES Appendix II (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Podocnemididae
Subfamily: Erymnochelyinae
Tribe: Erymnochelyini
Genus: Erymnochelys
Baur, 1888
Species:
E. madagascariensis
Binomial name
Erymnochelys madagascariensis

The Madagascan big-headed turtle (Erymnochelys madagascariensis)[1] is a turtle native to the waters of permanent slow moving rivers and lakes in western Madagascar. These turtles are critically endangered and have been evaluated to be the most endangered turtle in the world by a 2018 review.[3] Due to its ancient origins and threatened status, it is ranked as #1 on the EDGE of Existence programme's list of priority reptiles.[4]

Taxonomy

It is a highly evolutionary distinctive species, the only member of the ancient family Podocnemidae found outside of South America. It diverged from its closest living relative, Podocnemis, during the Late Cretaceous, about 78 million years ago.[5] 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.[6]

Description

The Madagascan big-headed turtle is one of the most endangered turtles in the world, and is also included in the Turtle Conservation Funds (TCF) top 25 endangered. It has a hard dark brown shell enclosing all the soft parts of the body and, as its name indicates, a very large head. Young turtles have a soft pattern of fine black lines on their shells, but they disappear with age.[7]

It is considered morphologically similar to another podocnemidid, the big-headed Amazon River turtle, which is similarly omnivorous unlike the herbivorous genus Podocnemis.[8][9]

Habitat

This species inhabits large areas with freshwater such as permanent slow streaming rivers, 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.[10]

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 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.

References

  1. ^ a b c Rhodin, Anders G.J.; van Dijk, Peter Paul; Inverson, John B.; Shaffer, H. Bradley (2010-12-14). "Turtles of the world, 2010 update: Annotated checklist of taxonomy, synonymy, distribution and conservation status" (PDF). Chelonian Research Monographs. 5: 000.136. doi:10.3854/crm.5.000.checklist.v3.2010. ISBN 978-0965354097. Archived from the original (PDF) on 2011-07-17.
  2. ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. ^ Gumbs, Rikki; Gray, Claudia; Wearn, Oliver; Owen, Nisha (2018). "Tetrapods on the EDGE: Overcoming data limitations to identify phylogenetic conservation priorities" (PDF). PLOS ONE. 13 (4): e0194680. Bibcode:2018PLoSO..1394680G. doi:10.1371/journal.pone.0194680. PMC 5894989. PMID 29641585.
  4. ^ "Species". EDGE of Existence. Retrieved 2023-06-07.
  5. ^ Vargas-Ramírez, Mario; Castaño-Mora, Olga V.; Fritz, Uwe (2008-12-20). "Molecular phylogeny and divergence times of ancient South American and Malagasy river turtles (Testudines: Pleurodira: Podocnemididae)". Organisms Diversity & Evolution. 8 (5): 388–398. Bibcode:2008ODivE...8..388V. doi:10.1016/j.ode.2008.10.001. ISSN 1439-6092.
  6. ^ Pérez-García, Adán (June 2023). "A lower Pliocene Erymnochelyini turtle (Pleurodira, Podocnemididae) from the Democratic Republic of Congo". The Anatomical Record. 306 (6): 1396–1410. doi:10.1002/ar.25073. ISSN 1932-8486. PMID 36151595.
  7. ^ "Madagascar big-headed turtle videos, photos and facts - Erymnochelys madagascariensis". Arkive. Archived from the original on 2011-11-09. Retrieved 2012-08-20.
  8. ^ Gentil, Eduardo; de Medeiros, Larissa Azevedo; Vogt, Richard Carl; Barnett, Adrian Ashton (2021-10-20). "Biology of the Big-headed Amazon River Turtle, Peltocephalus dumerilianus (Schweigger, 1812) (Testudines, Pleurodira): the basal extant Podocnemididae species". Herpetozoa. 34: 207–222. doi:10.3897/herpetozoa.34.e67807. ISSN 2682-955X.
  9. ^ Eisemberg, Carla C.; Reynolds, Stephen J.; Christian, Keith A.; Vogt, Richard C. (2017-02-01). "Diet of Amazon river turtles (Podocnemididae): a review of the effects of body size, phylogeny, season and habitat". Zoology. 120: 92–100. Bibcode:2017Zool..120...92E. doi:10.1016/j.zool.2016.07.003. ISSN 0944-2006. PMID 27552858.
  10. ^ "Madagascar big-headed turtle videos, photos and facts - Erymnochelys madagascariensis". Arkive. Archived from the original on 2011-11-09. Retrieved 2012-08-20.
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