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Thursday, December 27, 2012

Turtles and Tortoises

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Sea Turtles

Green Turtle (Chelonia mydas) Hawksbill Turtle (Eretmochelys imbricata) Leatherback Turtle (Dermochelys coriacea)
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Softshell Turtles

Asian Softshell Turtle (Amyda cartilaginea) Forest Softshell Turtle (Dogania subplana) Chinese Softshell Turtle (Pelodiscus sinensis) - introduced
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Native Terrapins

Malayan Box Terrapin (Cuora amboinensis) Asian Leaf Terrapin (Cyclemys dentata) Spiny Terrapin (Heosemys spinosa)
Malayan Flat-shelled Terrapin (Notochelys platynota) Black Marsh Terrapin (Siebenrockiella crassicollis)
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Some Introduced Turtles

Common Snapping Turtle (Chelydra serpentina) North Antillean Slider (Trachemys decussata) Red-eared Slider (Trachemys scripta)
Razorback Musk Turtle (Sternotherus carinatum) Indian Star Tortoise (Geochelone elegans)

Softshell Turtles (Family Trionychidae)

Softshell Turtles are so called due to the general lack of scales on their carapace. They have a nose like a pig snout. There are two native species - Asian and Forest Softshell Turtles; and an introduced species - the Chinese Softshell Turtle.

The Asian Softshell Turtle (Amyda cartilaginea) is also known as the Malayan Softshell Turtle. It is a forest species and can sometimes be found in the Central Catchment reservoirs. It is distinguished from the other by having a row of tubercles on the carapace just behind the neck. Its young has prominent yellow spots, but these tend to go away as it reaches adulthood.


Asian Softshell Turtle at Lower Peirce ©Tan KH

The Forest Softshell Turtle (Dogania subplana) can be distinguished from the rest by the straight sides of the carapace and a protruding line running along the centre of the carapace. Its young has eyespots on the carapace, but these tend to go away as it reaches adulthood. This species is also much smaller than the Asian Softshell Turtle. It can be found in forest streams.

The Chinese Softshell Turtle (Pelodiscus sinensis) is not native to Singapore. It is here due to the turtle soup industry. The softshell turtles found outside our forests are most likely this species.


Chinese Softshell Turtle at Botanic Garden. Left: ©Tan KH, right ©Lau SY

Native Terrapins

There are 5 native species in Singapore.

Malayan Box Terrapin (Cuora amboinensis) is a native terrapin has a distinctive plastron. A hinge allows the terrapin to shut its head and legs tightly in a protective shell. The carapace (left) is dark, while the plastron (right) is pale and mottled.


Malayan Box Terrapin at Springleaf ©Tan KH


Malayan Box Terrapin at Turut Track ©Danny Lau

Asian Leaf Terrapin (Cyclemys dentata) has a distinct vertebral keel and spiny rear carapace edge.


Asian Leaf Terrapin in Singapore Zoo ©Tan KH

Spiny Terrapin (Heosemys spinosa), also called Spiny Hill Terrapin, this uncommon forest terrapin is native to Singapore. It is so called due to the spiny edge of the carapace, which is more apparent in young specimens.


Spiny Terrapin: Bukit Timah ©Ben Lee and Sime Forest ©Lau JS


Spiny Terrapin at Bukit Timah ©Tan KH

Malayan Flat-shelled Terrapin (Notochelys platynota) has a flat carapace top, hence its name.


Malayan Flat-shelled Terrapin in Singapore Zoo ©Tan KH

Black Marsh Terrapin (Siebenrockiella crassicollis) has a jaw pattern that gives it a smiling face. The female has pale patches on the face, while the male lacks it.

Introduced Turtles

A number of alien turtle species has been released in the name of religious righteousness. The most common is the Red-eared Slider, which is a commonly released alien into ponds, canals and even our forest streams. Another non-native slider one may find in Singapore is the North Antillean Slider, which lacks the red "ears". Here is a non-exhaustive list:

Chinese Stripe-necked Turtle (Ocadia sinensis)
Malayan Giant Terrapin (Orlitia borneensis)
Giant Leaf Terrapin (Heosemys grandis)
Asian Forest Tortoise (Manouria emys)
Common Snapping Turtle (Chelydra serpentina)
North Antillean Slider (Trachemys decussata)
Red-eared Slider (Trachemys scripta)
Razorback Musk Turtle (Sternotherus carinatum)
Fly River Turtle (Carettochelys insculpta)
Indian Star Tortoise (Geochelone elegans)


North Antillean Slider at Botanic Gardens ©Lau SY. Red-eared Slider at Admiralty Park ©Tan KH


Indian Star Tortoise at Neo Tiew Lane 2 ©Lau SY


Razorback Musk Turtle at Central Catchment ©Ben Lee


Common Snapping Turtle at MacRitchie Reservoir ©Tan KH

Another one is the Fly River or Pignose Turtle (Carettochelys insculpta) sighted at Bedok Reservoir in 2008 by Jeremy Lee.

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