Big Headed Turtle

Maximum longevity: 27 years (captivity)

Platysternon megacephalum has no negative economic importance to humans.

Platysternon megacephalum is a very odd-shaped turtle with a huge head and a long tail that are almost the same size as its body. Total body length reachs up to 40 cm. Compared to most turtle species, the head of Platysternon megacephalum is oversized for its body. It's triangular and cannot be withdrawn into its shell. The turtle's skull is solid bone and, unlike most turtles, has no openings in the upper surface. Adults usually have a shell about 15-18 cm in length and it is more flattened than many other freshwater turtles. The carapace is yellow to brown, rectangular with a squared-off front and a more rounded back end, while the plastron is usually yellow. The toes are slightly webbed with strong claws. This species is noted to have legs covered with large scales and a tail that is very long and muscular. If needed, the tail can support the entire weight of the turtle.

There is no marked difference between the male and female, except the plastron of the male has a tendency to be more concave than the female.

The young are more brightly marked than the adults and have more pronounced serrations at the rear of the carapace. Also, the tail is often longer than that of an adult.

Range length: 40 (high) cm.

Sexual Dimorphism: sexes alike

Other Physical Features: ectothermic ; bilateral symmetry

Average lifespan
Sex: male
Status: captivity: 15.0 years.

Platysternon megacephalum lives in rocky, mountain streams and brooks. The water of these streams is usually fast moving and has a temperature of 12° - 17°C which is favored by this species.

Habitat Regions: freshwater

Terrestrial Biomes: mountains

Aquatic Biomes: rivers and streams

Other Habitat Features: riparian

This species is distributed throughout southeastern Asia. It occurs in southern China (including Hainan Island), southwest through northern Vietnam, Laos, Kampuchea, and northern Thailand to southern Burma.

Biogeographic Regions: oriental (Native )

Platysternon megacephalum is carnivorous. Using its strong beak and jaws, it consumes small marine and terrestrial animals such as fish, mollusks, and worms. It often searchs for food at night along stream bottoms and among low shrubs.

Primary Diet: carnivore (Piscivore , Molluscivore , Vermivore)

Platysternon megacephalum is a turtle that has been very common in food markets of southern China. This species is marketed by pet traders and is bought as souvenirs by tourists.

Positive Impacts: pet trade ; food

Platysternon megacephalum is one of several species of Asian turtles that have recently become heavily consumed in China and other Asian countries. Because of this, Platysternon megacephalum is now a rare find and the IUCN classifies it as an endangered species.

US Federal List: no special status

CITES: appendix ii

IUCN Red List of Threatened Species: endangered

The reproductive habits of Platysternon megacephalum are almost completely unknown except for a few details. This species has been reported to lay 1-2 white eggs at a time that measure about 37 mm by 22 mm. The eggs resemble bird eggs.

Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); oviparous

This turtle appears to be nocturnal, spending much of the day underwater burrowed into gravel deposits or hidden in rock crevices, generally at the stream edge or behind a waterfall (2) (4). At night, individuals emerge to search for food along the stream's bottom, and sometimes also out of the water along the stream's edge (4). Big-headed turtles are accomplished climbers, but not so well-equipped for swimming, with the ability to cling to rocks being more advantageous than swimming in the rapid waters in which it lives (2) (4). The diet is almost entirely carnivorous, with the species' strong, bony jaws allowing it to feed on crustaceans and molluscs, which form a large portion of the diet (4). The reproductive biology of big-headed turtles is almost completely unknown (6). A clutch reportedly contains one to six eggs, although two to three are more normal (2).

The big-headed turtle is legally protected in Myanmar and Thailand, and completely prohibited from export in China, Laos and Vietnam. However, extensive and significant illegal international trade apparently continues. Captive breeding cannot supply demand, bur does occur on an extremely limited scale in Thailand, and reportedly also occurs for commercial sale on Chinese turtle farms (8).

Aptly named, the big-headed turtle's most distinctive feature is its enormous, triangular head, which is so large in proportion to its body that it cannot be withdrawn into the shell for protection (4) (5). Instead, the top and sides of the turtle's head are covered with a large bony 'roof' that acts as armour and, unlike most turtles, the skull is solid bone (4) (5). The upper jaw is hooked and the edges of both jaws are lined with another tough horny covering, leaving only a narrow band of unprotected skin on the cheeks and running from the turtle's eyes to the corners of its mouth (4). Together with an oversized head, this odd-shaped turtle can be recognized by its exceptionally long, thin tail and particularly flattened shell, which is somewhat rectangular, being squared-off at the front and more rounded at the back (4) (6). While the upper shell (carapace) is yellow to dark brown, occasionally with a darker radiating pattern, the lower shell (plastron) is usually yellow, although this varies between the five subspecies (4) (6). The legs are covered in large scales, as is the long, thin, muscular tail, which is often used to support the animal's weight like an additional limb (6) (7).

The big-headed turtle prefers fast-flowing, cool, rocky mountain brooks and streams, usually narrower than a metre wide and less than 10 cm deep (2) (4).

Found from southern China, through northern Vietnam, Laos and northern Thailand, to southern Myanmar (2).

Classified as Endangered (EN) on the IUCN Red List 2006 (1), and listed on Appendix II of CITES (3). Five subspecies are currently recognised.

Legal and illegal trade are thought to pose the main threats to the big-headed turtle, which commonly appears in Asian food markets, and is in particular demand in China, Laos and Vietnam (1) (6) (8). The species is also sold by pet traders and, sadly, its increasing scarcity in the wild is only likely to lead to a greater demand for the species and higher market value, encouraging further collection from the wild. Furthermore, since the reproductive rate is thought to be very low, populations of this species are believed to be very sensitive to removal of individuals and slow to recover (8).

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