African helmeted turtle

The African helmeted turtle (Pelomedusa subrufa), also known commonly as the marsh terrapin, the crocodile turtle, or in the pet trade as the African side-necked turtle, is a species of omnivorous side-necked terrapin in the family Pelomedusidae. The species naturally occurs in fresh and stagnant water bodies throughout much of Sub-Saharan Africa, and in southern Yemen.

African helmeted turtle
Photographed in Uganda
Conservation status
Least Concern  (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Pleurodira
Family:	Pelomedusidae
Genus:	Pelomedusa Wagler, 1830
Species:	P. subrufa
Binomial name
Pelomedusa subrufa (Lacépède, 1788)
Synonyms[1]
? Testudo planitia Meuschen, 1778 Testudo subrufa Lacépède, 1788 Testudo galeata Schoepff, 1792 Testudo badia Donndorff, 1798 Testudo rubicunda Suckow, 1798 Emys galeata — Schweigger, 1812 Emys olivacea Schweigger, 1812 Emys subrufa — Schweigger, 1812 Hydraspis galeata — Bell, 1828 Pelomedusa galeata — Wagler, 1830 Pelomedusa subrufa — Wagler, 1830 Chelys (Hydraspis) subrufa — Gray, 1831 Hydraspis subrufa — Gray, 1831 Pentonyx capensis A.M.C. Duméril & Bibron, 1835 Pentonyx galeata — A.M.C. Duméril & Bibron, 1835 Emys (Emys) capensis — Fitzinger, 1835 Hydraspis (Pelomedusa) galeata — Fitzinger, 1835 Hydraspis (Pelomedusa) olivacea — Fitzinger, 1835 Hydraspis (Pelomedusa) planitia — Fitzinger, 1835 Pentonyx gehafie Rüppell, 1835 Pelomedusa gehafiae [sic] Gray, 1844 (ex errore) Pentonyx americana Cornalia, 1849 Pelomedusa mossambicensis W. Peters, 1856 (nomen nudum) Pelomedusa mozambica W. Peters, 1856 (nomen nudum) Pelomedusa nigra Gray, 1863 Pelomedusa gasconi Rochebrune, 1884 Pelomedusa galeata damarensis Hewitt, 1935 Pelomedusa galeata devilliersi Hewitt, 1935 Pelomedusa galeata galeata — Hewitt, 1935 Pelomedusa galeata nigra — Hewitt, 1935 Pelomedusa galeata orangensis Hewitt, 1935 Pelomedusa galeata subrufa — Hewitt, 1935 Pelomedusa galeata gehafie — Parker, 1936 Pelomedusa subrufa subrufa — Mertens, 1937 Pelomedusa subrufa damarensis — Mertens, 1937 Pelomedusa subrufa gehafie — Mertens, 1937 Pelomedusa subrufa wettsteini Mertens, 1937 Pelomedusa subrufa orangensis — Hewitt, 1937 Pelomedusa subrufa olivacea — Loveridge, 1941 Pelomedusa subrufa damaranus [sic] Heck, 1955 (ex errore) Pelomedusa subrufa nigra — Bour, 1986

Description

Side view of a captive specimen, showing claws and lighter underside

The marsh terrapin is typically a rather small turtle, with most individuals being less than 20 cm (7.9 in) in straight carapace length, but one has been recorded with a length of 32.5 cm (12.8 in). It has a black or brown carapace. The top of the tail and limbs are a grayish brown, while the underside is yellowish.

The male turtle is distinguished by its long, thick tail. A female tends to have a shorter tail and a broader carapace. A hatchling has a shell size of about 3 cm (1.2 in) in length, and is olive to black in color. It also has two small tubercles under the chin and musk glands in the sides of the carapace.

Uniquely, the genus Pelomedusa does not have a hinged plastron (lower shell). All the other species in the family Pelomedusidae, however, do have this feature with which they can, using muscles, close the plastron to the carapace to cover the head and front limbs. Unlike many chelonians, the African helmeted turtle is able, when it finds itself upside down, to right itself with a vigorous flick of its long muscular neck.[2]

Recent genetic research suggests that Pelomedusa comprises at least 10 different species, and not only one as previously thought. In the past the physical differences between populations were not regarded as substantial enough to recognise more than one species.[3]

Geographic range

The geographic range of P. subrufa covers a large portion of Africa, from the Cape Peninsula to the Sudan. It can be found as far west as Ghana and as far south as Cape Town. It has also been found in Madagascar and Yemen.[4]

Life history

Juvenile marsh terrapin

Head retracted into shell

Habitat

P. subrufa is a semiaquatic animal, living in rivers, lakes, and marshes, and it also occupies rain pools and places that are fertilized.

Its preference seems to be for standing water, such as swamps, pans, dams, and lakes. However it is found to a lesser extent along rivers. It is generally absent from regions that are mountainous, forested, or desert.[5]

Diet

The African helmeted turtle is an omnivorous eater and will eat almost anything. It may feed on carrion. The fine claws on its feet help it tear its prey apart.

Groups of P. subrufa have been observed capturing and drowning larger prey such as doves that come to drink; the commotion caused by these group attacks is often mistaken for crocodiles. All food is taken underwater to be eaten.[6]

Several large mammals such as warthogs, Cape buffalo, and rhinoceroses have recently been documented utilizing the turtles to remove parasites at popular wallowing holes. One such incident in Hluhluwe-iMfolozi park involved two African helmeted turtles removing ticks and blood-sucking flies from the body of a wallowing warthog. Though the turtles probably do not have a symbiotic relationship with these animals, it is very likely that the buffalo, rhinos, and warthogs seek them out and have learned to utilize them from past experiences. This behavior was documented for the first time in the September 2015 issue of Herpetological Review by Andy and Michelle Leighty Jones.[7]

Seasonal movements

During wet weather P. subrufa will often leave water bodies and embark on long overland journeys. During exceptionally dry weather when water bodies dry up, it will typically dig into the ground and bury itself until rains return; it has been known to spend months or even years in such a state. It will also hibernate during very cold weather, and aestivate during unusually hot, dry weather.

Reproduction

Courtship of P. subrufa is held year round. The male will follow the female, nodding his head in front of hers. If she is not responsive, she will nip and snap and walk away. If she is willing, she responds by nodding her head or just standing still, so he can mount her. While mating, each of the turtles shakes its head.

The female will lay two to ten eggs on average, normally during late spring and early summer. The eggs are placed in a flask-shaped nest about 4 to 7 in (10 to 18 cm) deep. The eggs hatch in 75– 90 days.[8]

Captivity

The African side-necked turtle is popular as a pet because of its unusual head tucking behavior.

References

1. Fritz, Uwe; Havaš, Peter (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 344–346. Archived from the original (PDF) on 2010-12-17. Retrieved 29 May 2012.
2. Baard EHW (1994). Cape Tortoises: Their identification and care. Cape Nature Conservation.
3. Fritz, Uwe; Petzold, Alice; Kehlmaier, Christian; Kindler, Carolin; Cambell, Patrick; Hofmeyr, Margaretha D.; Branch, William R. (2014). "Disentangling the Pelomedusa complex using type specimens and historical DNA (Testudines: Pelomedusidae)". Zootaxa 3795 (5): 501%u2013522.
4. Branch B (2001). Tortoises, Terrapins and Turtles of Africa. Cape Town: Struik Publishers. ISBN 978-1770074637.
5. Boycott R, Bourquin O (1988). The South African Tortoise Book. Johannesburg: Southern Book Publishers. p.60.
6. "Crocodile turtle or African helmeted turtle". Snakes-n-Scales. Archived from the original on 15 April 2014. Retrieved 4 May 2014.
7. "Turtles Groom Warthog in Never-Before-Seen Behavior". nationalgeographic.com. 8 October 2015. Retrieved 7 April 2018.
8. Orenstein, Ronald (2012). Turtles, Tortoises and Terrapins: A Natural History. Firefly Books. 448 pp. ISBN 978-1770851191

Further reading

• Boycott, Richard C.; Bourquin, Ortwin (2000). The southern African Tortoise Book – A Guide to southern African Tortoises, Terrapins and Turtles, Revised Expanded Edition. KiwaZulu-Natal: O. Borquin. 228 pp. ISBN 0-620-26536-1