Pelomedusa variabilis, Petzold & Vargas-Ramírez & Kehlmaier & Vamberger & Branch & Preez & Hofmeyr & Meyer & Schleicher & Široký & Fritz, 2014

Petzold, Alice, Vargas-Ramírez, Mario, Kehlmaier, Christian, Vamberger, Melita, Branch, William R., Preez, Louis Du, Hofmeyr, Margaretha D., Meyer, Leon, Schleicher, Alfred, Široký, Pavel & Fritz, Uwe, 2014, A revision of African helmeted terrapins (Testudines: Pelomedusidae: Pelomedusa), with descriptions of six new species, Zootaxa 3795 (5), pp. 523-548 : 543

Pelomedusa variabilis sp. nov.

Diagnosis: Medium- to large-sized helmeted terrapins with a known maximum straight carapacial length of 24.8 cm. Pectoral scutes mostly triangular without midseam contact, but terrapins with pectorals having narrow or wide midseam contact occur. One large undivided temporal head scale. Two small barbels under chin. Colouration extremely variable; very dark individuals are known, as well as specimens with light horn-coloured carapace and completely yellow plastron. Soft parts ventrally lighter than dorsally. Pelomedusa variabilis differs from all other Pelomedusa species by the presence of adenine (A) instead of cytosine (C) or thymine (T) at position 189 and by the presence of adenine (A) instead of guanine (G) at position 322 of the 360-bp-long reference alignment of the 12S rRNA gene (Supporting Information).

Holotype: Senckenberg-Museum , Frankfurt am Main ( SMF 58075, subadult male, Gold Coast, Ghana; leg. H. Lang, 18 February 1957; Fig. 5 bottom).

Description of the holotype: Straight carapacial length 10.3 cm, plastral length 8.7 cm. Pectoral scutes triangular, widely separated, without midseam contact. Temporal scales undivided; injury on the right side of head. Two small barbels under chin. Carapace covered by algae; plastron dark brown, seams distinctly lighter. Soft parts dorsally dark grey; throat cream-coloured, ventral side of legs greyish brown. Tail long.

Paratypes: Museum für Tierkunde, Senckenberg Dresden ( MTD T 33818–33819 , male and female, Ghana; MTD T 35041, juvenile, Ghana); The Natural History Museum, London ( BMNH 1863.3 .27.1, male, Ghana; BMHN 1927.8.27.240–242, juveniles, Ghana); Zoologisches Forschungsmuseum Alexander Koenig , Bonn ( ZFMK 47521–47523 , juveniles, Achimota , Greater Accra Region, Ghana) .

Derivatio nominis: The species name variabilis is an adjective in female gender, referring to the variable morphology of the new species.

Distribution: Genetically verified records for P. variabilis are only known for Ghana and the Ivory Coast ( Vargas-Ramírez et al. 2010; Wong et al. 2010; Fritz et al. 2014).

Remarks: Pelomedusa variabilis corresponds to mtDNA lineage II of Vargas-Ramírez et al. (2010). It belongs to the northern clade of Pelomedusa and is according to our mtDNA analyses sister to P. olivacea ( Fig. 1 ).

Male helmeted terrapins from the Ivory Coast were reported to have red-spotted nearly white heads ( Bull & Legler 1980). However, specimens with such colouration were never seen during fieldwork by M.-O. Rödel (pers. comm.). Among the 11 specimens of the type series, there are nine terrapins with triangular pectoral scutes without midseam contact; in another specimen ( MTD D 33819) the tip of the left pectoral just reaches the midseam, whereas the right pectoral does not, and in the paratype BMNH 1863.3 .27.1 the pectoral scutes are rectangular with wide midseam contact .

For the monogenean flatworm Polystomoides nabedei possibly parasitizing Pelomedusa variabilis , see under P. olivacea .

Figures

FIGURE 1. Maximum Likelihood tree for helmeted terrapins (Pelomedusa spp.) using 1848 bp of mitochondrial DNA (12S, cyt b, ND4+tRNAs), rooted with Pelusios sinuatus. Terminal clades collapsed to cartoons. The topology of the Bayesian 50% majority rule consensus tree was identical. Numbers along branches indicate bootstrap support and clade support under BI (posterior probabilities) greater than 50 or 0.95, respectively. Asterisks represent maximum support under both methods. Colours and symbol correspond to the map (Fig. 2). On the right, proposed species names indicated; in brackets, mtDNA lineages. For clade membership of individual samples, see Table S1. The questionable sample MTD T 5484 from Swellendam District (Western Cape), South Africa, is highlighted in red (see text). The shown terrapins are Pelomedusa neumanni (top; Kakamega, Kenya) and P. galeata (bottom; Port Elizabeth, South Africa—photos: H. Prokop and W.R. Branch).

FIGURE 5. Dorsal and ventral aspects of the holotype of Pelomedusa somalica sp. nov. (BMNH 1970.1481, adult, Borama district, Awdal, Somaliland/Somalia; top) and of Pelomedusa variabilis sp. nov. (SMF 58075, subadult male, Gold Coast, Ghana; bottom). Scale bars, 3 cm. Photos: A. Petzold and E. Morawa.