African Helmeted Turtle

Family: Pelomedusidae - African Side-necked Turtles

Order: Testudines - Turtles

Class: Reptilia

Phylum: Chordata - Vertebrates

Kingdom: Animalia

Red List status: Not Listed

Pelomedusa subrufa (Lacpde, 1788)
African helmeted turtle. Tulear Region, Madagascar

                                Adult              Hatchling

Carapace length:    150-320 mm   25-30 mm

 

Weight: 2.5 kg

RANGE

Much of mainland Africa, from Ghana south to South Africa and east to western Madagascar and Yemen. In Madagascar populations appear to be widespread in the island's subarid south, with seemingly isolated populations in northwestern dry forest.

            Range            Description            Habitat            Behaviour            Biology            References

Other common names: Black African helmeted turtle, marsh terrapin, helmeted terrapin, Madagascar side-necked turtle

 

DESCRIPTION

A moderate-sized turtle, with five-clawed, webbed feet, a large head with a protruding snout, and an elongate profile. The flattened carapace is olive or brown, and the scales of the head, body and limbs are greyish-brown. Patterning is normally absent, but blotches or light radial patterning may be present Two small barbels (tentacles) are present beneath the chin; these are involved in mating. The plastron is yellow with brown blotches, and the throat may also be yellow.

Juveniles have olive skin, and the carapace may be black and orange. Often black and cream barring is present along the edge of the carapace where it joins the plastron.

Similar species: The African helmeted turtle retracts its head sideways into its shell for protection, not pulling it straight backwards. This feature, as well as its aquatic habitat preference and very weakly-domed carapace, distinguishes Pelomedusa subrofa from tortoises. The five-, rather than four-clawed feet distinguish it from the endemic Malagasy genus Erymnochelys. Unlike all other freshwater turtles in Madagascar, and most in East Africa, the African helmeted turtle has an immobile, unhinged plastron. It is therefore unable to raise the lower portion of its shell to cover its head and limbs when retracted, as other turtles can.

 

HABITAT

Widely distributed where stagnant water occurs. In Madagascar, the species is mostly associated with temporary waterbodies ranging from ponds to puddles in the drier south and west of the country. On the African mainland, the species appears to utilise a wider variety of habitats, occurring in lakes, rivers and marshes as well as temporary pools, in environments ranging from moist savannah to semi-desert. It is rare in large rivers.

Elevation: 0 - 1,600 m

 

BEHAVIOUR

An aquatic turtle which typically basks in water, although animals may migrate some distance across land between suitable waterbodies. They are fast swimmers; if threatened on land they will flee or attempt to bury themselves in mud. Animals may be unpalatable to predators due to their pungent musk. African helmeted turtles aestivate underground during the dry season, and often emerge in large numbers following heavy storms.

Courtship and reproductive behaviour: Males trail females in the breeding season. A male will touch the female's vent and hindquarters to elicit a response, or biting the limbs and tail if this fails. Upon acceptance, he will grab the female's shell and touch her head with his barbels. Flask-shaped nests are constructed 10-17 cm deep.

Diet: This species subsists largely on terrestrial and freshwater invertebrates, and fish. However, cases have been reported of animals working together to take birds that come down to drink. Plant material is sometimes taken.

 

BIOLOGY

Life cycle: A single clutch of 13 or more eggs are laid in a season; exceptionally clutches of up to 42 eggs have been reported, but most contain 16 or fewer. Eggs measure 38 x 22 mm, and hatch after 75-90 days.

Lifespan: Up to 16 years in captivity.

 

REFERENCES

 

African helmeted turtle, Wikipedia

Glaw, F. and Vences, M. (2007) A Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Cologne, Vences & Glaw Verlag: 496pp

Spawls, S., Howell, K., Drewes, R. and Ashe, J. (2004) A Field Guide to the Reptiles of East Africa A&C Black, London: 543pp