Black marsh turtle  (Siebenrockiella crassicollis)

Also known as the ‘smiling terrapin' due to its upwardly curved jaw line (4), the black marsh turtle is a largely aquatic turtle that has assumed religious significance and is often kept around temples in Asia (5). While most black marsh turtles are small, measuring only around 17 centimetres, some individuals may be twice the size (2). It has a black upper shell, or carapace, that is strongly serrated on the back edge (6). The shell on the underside of the turtle, or plastron, is uniformly black or dark brown to yellowish-brown with dark blotches or patterns. The large and rather broad head is black to dark grey with a faded white, cream or yellow spot behind each eye. The snout is short and slightly projecting and the jaws are cream to tan in colour. The limbs, tail and thick neck of the black marsh turtle are dark grey to black. The limbs have webbed toes, adapted to an aquatic lifestyle, and the front surface of each limb is covered with large scales. Male black marsh turtles have a slightly concave plastron and thicker, longer tails than the females, which have flat plastrons. The light head spots also often fade out in males, but are retained in females (6).

Occurs in Southeast Asia (2), from southern Vietnam, westward through Thailand to Myanmar, and southward through Malaysia to Sumatra, Java and Borneo (6).

The black marsh turtle is a largely aquatic species that inhabits shallow streams, rivers, ponds, lakes, swamps and, as its name suggests, marshes. It prefers areas with slow currents, soft bottoms and abundant vegetation (2) (6).

The primarily carnivorous black marsh turtle feeds on worms, snails, slugs, shrimp, and amphibians, and also scavenges dead and decaying animals (2) (6). Occasionally, it may also consume rotten plants that have fallen into the water. Most of this food is captured and eaten underwater, but during the night the turtle may venture onto land to forage or to mate. When not feeding, the black marsh turtle spends much of the time partially buried in mud at the bottom of its aquatic habitat (6).

During courtship, a male black marsh turtle pursues a female whilst bobbing its head and inflicts bites on the female's legs before mating. The nesting season, at least in Malaysia, extends from April through June, when females may lay three or four clutches, each consisting of one or two eggs. The eggs are incubated for 68 to 84 days, after which the tiny hatchlings, measuring less than five centimetres, emerge (6). Unlike the majority of turtles, the sex of hatchlings is not determined by the temperature during incubation, but is genetically determined (7).

The main threat to this freshwater turtle species is capture for local and international trade (8), as pond turtles are widely eaten throughout its range (2). In Cambodia and Vietnam the black marsh turtle is considered Endangered due to the high levels of exploitation (1). Turtle populations have been heavily exploited in Vietnam since 1989, and hunting and collecting pressure impacts populations even within so-called protected areas (9). Compounding the impact of exploitation is the almost ubiquitous threat of habitat loss and degradation (1). Fishing may also impact populations of the black marsh turtle, either through reducing food availability for this carnivorous species, or through the use of electric fishing devices which harms turtles and other aquatic species in the vicinity (9).

The black marsh turtle is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in this species should be carefully monitored to ensure it is compatible with the species' survival (3). In Myanmar and Thailand the black marsh turtle is protected, and Vietnam prohibits the export of all wild animals (8), but despite this, hunting and collection still poses a threat to this species' existence and thus more effective enforcement of legislation is clearly needed. Likewise, whilst the black marsh turtle occurs in a number of protected areas, such as Cat Tien National Park in Vietnam, hunting often still occurs in these regions. In Cat Tien National Park, and other protected areas in Vietnam, a shortage of park guards and a lack of coordination between the local government and park officials in law enforcement, lessens the protection that these areas could offer the Vulnerable black marsh turtle (9).

For further information on the conservation of Asian turtles see:

• Asian Turtle Conservation Network:
  www.asianturtlenetwork.org

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk