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]
Background
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
genusPlatysternon, 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 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]
Diet
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]
Exploitation
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]