Big-headed turtle

Big-headed turtle
A big-headed turtle (Platysternon megacephalum)
Conservation status
Critically Endangered  (IUCN 3.1)[1]
CITES Appendix I (CITES)[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Superfamily:	Testudinoidea
Family:	Platysternidae Gray, 1869[3]
Genus:	Platysternon Gray, 1831[3]
Species:	P. megacephalum
Binomial name
Platysternon megacephalum Gray, 1831[3]
Synonyms[4]
Platysternon megacephalum megacephalum Platysternon megacephalum Gray, 1831 Platisternon megacephalus Gray, 1834 Platysternon megacephalus Gray, 1835 Emys megacephala Schlegel, 1838 Platysternon magacephalum Fitzinger, 1843 (ex errore) Platysternum megacephalum Boulenger, 1889 Platysternon platycephalum Mertens, 1959 (ex errore) Platysternum megalocephalum Stanek, 1959 (ex errore) Platysternon megacephalum megacephalum Wermuth, 1960 Platysternon magacephalum megacephalum Pritchard, 1979 Platysternon megacephalum tristernalis Schleich & Gruber, 1984 Platysternon megacephalum tristornalis Alderton, 1988 (ex errore) Platysternon megacephalum peguense Platysternon peguense Gray, 1870 Platysternon megacephalum peguense Wermuth, 1960 Platysternon megacephalum vogeli Wermuth, 1969 Platysternon megacephalum penguense Nutaphand, 1979 (ex errore) Platysternon megacephalum penuense Nutaphand, 1979 (ex errore) Platysternon megacephalum peguensis Sharma, 1998 (ex errore) Platysternon megacephalum shiui Platysternon megacephalum shiui Ernst & McCord, 1987

The big-headed turtle (Platysternon megacephalum) is a species of turtle in the family Platysternidae from Southeast Asia and southern China.^[3]

Previously considered a distinct family placed on occasion in "Kinosternoidea", it was later moved to the Emydidae. This, as well as the subfamily and the genus Platysternon, are monotypic.

The big-headed turtle is named after its unproportionally large head which leads to an inability to retreat into its shell. In order to protect itself it instead has an armored head and sharp beak.^[5]

The big-headed turtle is found in Cambodia, China, Laos, Myanmar, Thailand, and Vietnam.^[1][3] It is commonly found in fast flowing streams and waterfalls in rocky areas. [1]

The big-headed turtle is known to readily climb over obstacles in and around rivers and fast streams, using its tail as a prop to extend the reach of its strong claws. It also uses its beak to assist in climbing.^[6] It has been reported to climb trees and bushes. These turtles generally move more during the night, and are not prone to moving long distances. They have a general daily range of 0-89.6m and males tend to move further than the females in this species.^[7] They are not strong swimmers, and when swimming, this species occasionally arches its tail in the manner of a scorpion.^[6] The big-headed turtle cannot pull its head in its shell. That being the case, it will not hesitate to use its powerful jaws to defend itself. Its diet consists of fish, snails and worms.^[8] It also tends to eat fruits like the Machilus spp., as well as insects, crabs and mollusks.^[9]

Originally assumed to be strictly carnivorous, this appears to be an opportunistic feeder with a significant shift towards omnivory or herbivory. Using fecal matter, big-headed turtles are found to consume fruits (Machilus and Turpinia arguta), terrestrial insect adults/larva and aquatic larva (Coleoptera, Homoptera, Hymenoptera, Isoptera, Lepidoptera, Mantodea, Orthoptera, Diptera, Ephemeroptera, Odonata and Tricoptera), mollusks (Sulcospira hainanensis), frogs, rodents, and freshwater crabs. Their eating behavior changes depending on the environmental conditions, but predominantly consume fruits. Seeds partially digested were found to have increased germination success after turtle excretion, possibly connecting their frugivore habits to environmental conditions.^[10]

The big-headed turtle is found quite frequently in illegal wildlife trade.^[5] It is readily consumed in Asia and is frequently a market item. Hunters capture them on lines with baited straight pins, so this species is rapidly disappearing in the wild.^[11] The species is also threatened by its use in the pet trade.^[1]

• P. m. megacephalum, China, 1831^[3]
• P. m. peguense, Myanmar and Thailand, 1870^[3]
• P. m. shiui, Cambodia, Laos and Vietnam, 1987^[3]

In addition, two other subspecies, P. m. tristernalis (1984) and P. m. vogeli (1969), have been given, but may be invalid.^[12]

Bibliography

• Rhodin, Anders G.J.; Paul van Dijk, Peter; Iverson, John B.; Shaffer, H. Bradley (2010-12-14). "Turtles of the World 2010 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution and Conservation Status" (PDF). Archived from the original (PDF) on 2011-07-17. Retrieved 2010-12-15.
• Fritz, Uwe; Havaš, Peter (2007-10-31). "Checklist of Chelonians of the World" (PDF). Archived from the original (PDF) on 2011-05-01. Retrieved 2010-12-29.
• Pritchard, D. 1979. Encyclopedia of Turtles. New Jersey: T.F.H. Publications, Inc. Ltd.
• "The Big-headed Turtle (Platysternon megacephalum) Project". asianturtleprogram.org. Retrieved 2023-03-14

Wikimedia Commons has media related to Platysternon megacephalum.

• Big-headed turtle (Platysternidae)
• (Chinese) Big-headed turtle
• (Spanish) Platysternon megacephalum Archived 2016-03-04 at the Wayback Machine