Pantanal swamp turtle  (Acanthochelys macrocephala)

Classified as Near Threatened (NT) on the IUCN Red List (1).

Discovered as recently as 1984, the Pantanal swamp turtle is the largest turtle species of its genus. The head is extremely wide and ends in a blunted snout, with two small barbels on the chin. Colouration of the limbs, neck and head is dark greyish-brown above, contrasted with cream or yellow below. The domed shell is broad and oval, with large dark brown or blackish brown scutes on the upperside, and yellow scutes underneath (2). Hatchlings resemble the adult, but possess orange-red spots on the upper and lower parts of the shell and on the sides of the neck (3).

The Pantanal swamp turtle is found in the upper Rio Paraguay drainage, running from south-western Mato Grosso, Brazil, to Paraguay (2) (3). This drainage forms part of the Pantanal swamplands, the largest wetland in the world (4), as well as part of the Chaco region of Paraguay (2) (3). In addition, this species occurs in the upper Rio Mamoré drainage in central Bolivia (2) (3).

Within the Pantanal swamplands, the Pantanal swamp turtle inhabits marshes and slow-flowing streams, while in the Rio Mamoré, it is found in shallow rivulets off the main river channel (2).

A little-known species, in the wild the Pantanel swamp turtle mainly feeds upon snails, crushing the shells between the horny plates that line its jaws. In captivity, however, it will readily take fish and other animal flesh (2). Unlike some turtles, which can protect their head by withdrawing it straight back inside the shell, the Pantanal swamp turtle is only capable of turning its neck to the side, thereby concealing its head just under the front lip of the shell (5).

The Pantanal swamp turtle nests from April to May, at the end of the rainy season when the flood waters begin to recede. The female lays a clutch of four to eight round, hard-shelled eggs, which hatch after around six months (3).

Pantanal swamp turtles are imported in low numbers into the USA for the pet trade (6), and while this is unlikely to be having a severe impact on the population, the current lack of regulation and monitoring means that it could become a problem in the future. In addition, because this species has specific habit requirements, it is particularly vulnerable to detrimental human activities (7), as well as the influence of climate change (8).

While there are currently no specific conservation measures in place for the Pantanal swamp turtle (1), its range falls within the World Heritage Pantanal Conservation Complex, a cluster of four protected areas with a total area of 187,818 hectares, located in the south-west of Mato Grosso, Brazil (4).

View information on this species at the UNEP World Conservation Monitoring Centre.

To learn more about turtle conservation visit:

• Chelonian Research Foundation:
  www.chelonian.org
• Behler Chelonian Center:
  http://chelonianconservation.org