East African black mud turtle (Pelusios subniger)

Also known as: East African side-necked turtle
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderTestudines
FamilyPelomedusidae
GenusPelusios (1)
SizeLength: 20 cm (2)

Classified as Least Concern (LC) on the IUCN Red List (1). Subspecies: Pelusios subniger parietalis (Seychelles black mud turtle) is classified as Critically Endangered (CR) on the IUCN Red List (1).

Like all Pelusios species the East African mud turtle is rather drab in colour (3). It has a moderately domed, oval, dark-coloured carapace (upper shell) with no keel or serrations (2) (3). By contrast, the plastron (lower shell) is yellow with dark seams or just a dark border, although colour markings can vary significantly (2) (3). The large head is usually brown, sometimes dappled with small black spots, while the jaws are tan or yellow and the neck, limbs and tail are grey (2) (3).

This is a tropical turtle from eastern and south-eastern Africa, Madagascar and the Seychelles (2) (3). The Seychelles black mud turtle subspecies is confined to the Seychelles islands of Mahé, Cerf, Praslin, La Digue, Fregate and Silhouette (1).

This aquatic species is usually found in shallow waters of soft-bottomed marshes, swamps, streams, rivers and ponds in the savannah across much of its range, although it has been recorded from temporary water bodies in south-eastern Africa (2) (3).

The East African black mud turtle is reportedly nocturnal. Individuals have been known to aestivate in underground burrows when the temperatures become too warm, too cold, or conditions become too dry, re-emerging again when conditions return to a suitable level (4). The diet includes insects, worms, snails, small fish, amphibians and crabs, as well as aquatic plants such as water grasses (2) (4).

In captivity, the East African black mud turtle has been recorded laying its eggs in February and March, with hatchlings emerging around 58 days later (when incubated at 28 to 30°C), although this may vary with location (4). Three to twelve eggs are produced per clutch by the female and buried in a flask-shaped nest cavity (2) (5). In the Seychelles, the Seychelles black mud turtle subspecies lays its eggs between December and February (1).

Although over-collection from the wild may pose a potential threat to the East African black mud turtle, which has been reaching North American pet markets in increasing numbers, the species is not considered endangered, having an expansive range and occurring in relative abundance in the wild (4). By contrast, the Seychelles black mud turtle is considered Critically Endangered on the IUCN Red List, due to massive loss and deterioration of its habitat (2), which has resulted in the subspecies now occupying less than 20 percent of its former range (1). The marsh habitat of the Seychelles black mud turtle subspecies is declining in both quality and quantity due to pollution, drainage and invasive plant species (water lettuce invasion). Predation by cats and dogs is likely to be a significant cause of population decline on Mahé, Praslin and La Digue (1) (6). In 1999, the Anse Kerlan marsh on Praslin was drained to allow expansion of the airport on the island and the development of a golf course, eliminating the main Seychelles black mud turtle population in the process. In 2005, a total population estimate of just 584 to 728 individuals was given for this rare subspecies (6).

The Seychelles black mud turtle is protected under Seychelles law and, although it does not occur in any reserves, it can be found in conservation-managed areas on Fregate and Silhouette (1). Captive breeding has been established at the Nature Protection Trust of Seychelles (NPTS), leading to an experimental reintroduction of captive-bred individuals on Silhouette. However, there is an urgent need to raise the profile of marsh conservation in the Seychelles before the last remaining fragments are lost (6).

For more information on the East African black mud turtle see:

Authenticated (07/03/08) by Dr Justin Gerlach, Scientific Co-ordinator, The Nature Protection Trust of Seychelles.
http://islandbiodiversity.com

  1. IUCN Red List (February, 2008)
    http://www.iucnredlist.org
  2. Ernst, C.H., Altenburg, R.G.M. and Barbour, R.W. (1997) Turtles of the World. ETI Information Systems Ltd, Netherlands.
  3. The Turtle Puddle (December, 2006)
    http://www.turtlepuddle.org/exotics/pelusios.html
  4. Jacksonville Zoo and Gardens (December, 2006)
    http://www.jaxzoo.org/things/biofacts/EastAfricanMudTurtle.asp
  5. U.S. Geological Survey (USGS): Non-Indigenous Aquatic Species (NAS) (December, 2006)
    http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=2281
  6. Nature Protection Trust of Seychelles: Seychelles Terrapin Conservation Project (December, 2006)
    http://islandbiodiversity.com