Siebenrockiella crassicollis Gray, 1831
by Mr. Tan Kok Kiat & Mr. Kaviarasu Munian
Siebenrockiella crassicollis Gray, 1831
by Mr. Tan Kok Kiat & Mr. Kaviarasu Munian

Siebenrockiella crassicollis is a hard shelled turtle in the family Geoemydidae. This monotypic species is commonly known as the Black Marsh Turtle. The genus is named in honour of an Austrian zoologist, Friedrich Siebenrock, while the species epithet crassicollis is derived from two Latin words, crassus and collum meaning "thick neck". The turtle has a characteristically thick neck, forming a collar around the head when it is retracted into the shell; hence its species name. It is native to Cambodia, Indonesia, Malaysia, Myanmar, Singapore, Thailand and Vietnam.

The Black Marsh Turtle is easily recognized by its upwardly curved jaw line which gives it the common name of "Smiling turtle". It can grow up to 20 cm (straight carapace length) (Das, 2010). The ovoid carapace is dark grey or nearly black, while the plastron is pale grey with large dark areas in each scute. The juvenile has light coloured spots on the head. These light coloured spots remain in the adult female while they will fade with growth in the male (Das, 2010). The female may lay up to four clutches of eggs, which each clutch containing one or two eggs. This happens between the month of April and the end of June (Franklin, 2007).

The Black Marsh Turtle is nocturnal and comes out during the night to forage and/or to mate. It lives in stagnant or sluggish water bodies including marshes, swamps, ponds, streams and lakes. It is known to be highly carnivorous; it has a broad head and strong jaws for crunching mollusc and carrion bones (Hopson, n.d.). However, it is considered an omnivore too as its diet also includes rotting plants, fruits and carcasses (Moll & Moll, 2004).

This species may sometimes be overlooked as it rarely gets into the headlines. The Black Marsh Turtle is listed in CITES Appendix II, which means that this species is not necessarily threatened with extinction, but its trade must be controlled in order to avoid utilization incompatible with their survival (CITES, 2018). Commonly, this turtle is being traded for food and traditional medicine. Some turtles are kept in ponds of temples, e.g. in Thailand where some Thai people believe that the Black Marsh Turtles carry the souls of people who died saving others from drowning. The Black Marsh Turtle is listed as Vulnerable by the International Union for Conservation of Nature (IUCN) due to both exploitation and habitat conversion and loss (IUCN, 2018). Official records indicate that 135,000 individuals were exported from Malaysia in 1999 (IUCN, 2000) and sold at a price of RM 5 per individual in the local market, with an estimated 30 individuals sold per week (Sharma, 1999). Due to high demand, the current price for a Black Marsh Turtle has gone up to 50 USD (Anon., 2018) or approximately RM 195. This vulnerable species is listed as protected wildlife under the first schedule of the Wildlife Conservation Act 2010, to control its export trade.


  1. Black Marsh Turtles for Sale. First Choice Reptiles. Retrieved January 29, 2018, from
  2. Das, I. (2010). A Field Guide to the Reptiles of South-East Asia. New Holland Publishers (UK), England. pp. 369.
  3. Franklin, C.J. (2007). Turtles: An Extraordinary Natural History 245 Million Years in the Making. Voyageur Press, United States of America. pp. 165.
  4. Hopson, M.Borneo Black Leaf Turtle Sienbenrockiella crassicollis. Retrieved January 04, 2018, from
  5. How CITES works. Retrieved January 04, 2018, from
  6. Moll, D. & Moll, E.O. (2004). The Ecology, Exploitation and Conservation of River Turtles. Oxford University Press, United States of America. pp. 420.
  7. Sharma, D.S.K. (1999). Trade Review: Tortoise and Freshwater Turtle Trade and Utilisation in Peninsular Malaysia. A Traffic Southeast Asia Report. TRAFFIC Southeast Asia, Petaling Jaya, Malaysia.
  8. Siebenrockiella crassicollis. (Errata version published in 2016): e.T39616A97377799. Retrieved January 04, 2018, from
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