Friday, January 25, 2013

Spiny Hill Terrapin (Heosemys spinosa)



Spiny Hill Terrapin (Heosemys spinosa), Bukit Timah Nature Reserve


I had the most pleasant surprise of meeting my first Spiny Hill Terapin on 8 Jan 2013. My colleague spotted this beautiful creature after a heavy rain. Knowing that this was a rare sight, we took it into the office to record measurements and to take photographs. Unfortunately I only had my iPhone with me so I apologise for the grainy photos.

But before reading on, you might be asking, "what is the difference between a Turtle, Tortoise and a Terrapin?" Well, all three are reptiles and the main differences between each can be generally put as such: Turtles have webbed feet and live in the sea, tortoise have claws and live on land, and terrapins are turtles that live on land and near fresh or brackish water such as streams and ponds.






All three have similar structures which comprises mainly of the upper shell (carapace) and the lower shell (plastron). These shells are covered in hard protective plates called scutes. The patterns and arrangement of scutes, plus the overall look of the individual are often the first visual sign to aid identification in the field



In the case of the Spiny Hill Terrapin, the distinctive serrations along the margins of the carapace indicate that this is a juvenile. Adults will lose the deep serration for most of the margin, replacing them with a more rounded edge. Only slight serrations are left at the rear of the carapace.


Adult Spiny Hill Terrapin (photo from www.ecologyasia.com)


This shy creature is a native of our forests and is the only true forest terrapin we have in Singapore. This terrapin is mainly a land dweller and is encountered on the forest floor sometimes not far away from water. We have not observed any for quite some time so it was an even greater joy to know that they are breeding. I found out yesterday that about the same time, another juvenile was spotted at another part of the Central Nature Reserve. Not much is known about their breeding habits but at least we know that this time of the year is when we can expect juveniles to be around.

We took measurements of the one at BTNR and he/she was tiny! (i am still unsure of the sex of this terrapin). The carapace length was 6.5cm and the weight was 48.9g. An adult can attain a carapace length of more than 20cm.


A closer look at the marginal serrations and the vertebral keel that runs down the centre of the carapace. (note the handy Moleskine grid notebook below!)





View of plastron. Note the reddish scutes on the feet.









After a quick round of photo-recording and measurements, we released it back into the reserve. Good luck little one, we look forward to seeing you again!

















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