The Spiny Terrapin (Heosemys spinosa) or Spiny Hill Terrapin or Spiny Turtle is a globally endangered species of forest terrapin.
It normally inhabit rainforest near shallow, clear streams. Normally it camouflage itself well among the leaf litter and can be more easily spotted once it moves.
It is named as such because the juveniles have a carapace which is heavily serrated at the margin. As it grows older, this is worn down. So one can tell whether it is a juvenile or adult by looking at the extent of the spines. The purpose of the spine is believed to be defensive in nature, so as to prevent predator from swallowing it whole. Perhaps as it grows older and bigger, such spines are no longer essential.
On a very wet day at Sime Forest in July 2012, I had the misfortune to have the main exit from the trail flooded. Even after the rain subsided, the stream was too overflowing with water to cross safely. So I decided to make a long detour to another exit. This entail climbing up a hill and descending. It was not a pleasant thing to do, considering that the descending part was waterlogged as well.
(Dillenia Hut flooded, as well as the nearby stream where I normally cross to exit. Photo taken from my phone.)