The “true“ Pelomedusa subrufa remains relatively small, and it is a
eritable survivor: In Namibia, it can endure drought periods of
up to 6 years by burying itself underground. A. Schleicher
Scentists at the Senckenberg Research Institute revealed that the African helmeted terrapin Pelomedusa subrufa actually comprises at least 10 different species. Until now, it had been considered to represent a single species, with a distribution spanning most of Africa, Madagascar and Arabia. The new classification also results in a revised assessment of its conservation status: at least one of the newly described species is seriously endangered. The underlying studies were published in the scientific journal Zootaxa.
The African helmeted terrapin Pelomedusa subrufa prefers small water bodies, but it is also able to survive drought periods of several years -- by burrowing underground. Reaching a maximum shell length of 30 cm, these turtles are widely distributed. They are found from South Africa north to the Sahel Zone, in Madagascar and on the Arabian Peninsula. This wide distribution range and their ability to survive long periods of drought led to its classification as "not endangered."
"However, our research shows that previous assumptions were basically incorrect," says Professor Uwe Fritz, director at Senckenberg in Dresden. In cooperation with an international team of scientists, among them researchers from South Africa and Namibia, he examined the turtles using morphological methods and the molecular genetic approaches. "Our results indicate that not one, but at least ten species are involved in this complex -- and perhaps even more," explains Fritz.
Altogether, the scientists from Dresden examined approximately 350 turtles, 200 of which underwent genetic testing. Among others, they also genetically analyzed samples from museum specimens -- some more than 100 years old.
"Up to now, the African helmeted terrapin was considered a widely distributed species and, therefore, not endangered, since it was assumed that the same species occurred throughout Africa. Our research shows that many distinct species are involved and that the distribution of each species is much more limited," says Fritz. "Due to this, some of the species are probably much more endangered than previously assumed." One of the newly described turtles may actually be threatened by extinction, due to severe water shortage in its home on the southwestern Arabian Peninsula.
However, there is also good news at least for some countries: South Africa has gained an additional turtle species. Thanks to the recent split, two species of helmeted terrapins are now found in the country, one is distributed over most of South Africa, while the second species is confined to South Africa's Limpopo province. This even topped by Tanzania, where three distinct species occur!
Uwe Fritz, Alice Petzold, Christian Kehlmaier, Carolin Kindler, Patrick Cambell, Margaretha D. Hofmeyr & William R. Branch. Disentangling the Pelomedusa complex using type specimens and historical DNA (Testudines: Pelomedusidae). Zootaxa, 3795 (5): 501%u2013522
Alice Petzold, Mario Vargas-Ramirez, Christian Kehlmaier, Melita Vamberger, William R. Branch, Louis du Preez, Margaretha D. Hofmeyr, Leon Meyer, Alfred Schleicher, Pavel Široky & Uwe Fritz Zootaxa. A revision of African helmeted terrapins (Testudines: Pelomedusidae: Pelomedusa), with descriptions of six new species. Zootaxa, May 2014