Pelomedusa, Wagler, 1830

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 : 543-544

Pelomedusa candidate species A

This candidate species from Cameroon corresponds to mtDNA lineage I of Vargas-Ramírez et al. (2010). It is genetically clearly distinct and differs in 12S and cyt b sequences by uncorrected p distances resembling the divergences among other Pelomedusa species ( Tables 1 and 3). Since there is just one genetically verified voucher specimen available (Zoologisches Forschungsmuseum Alexander Koenig, Bonn, ZFMK 15171, Mokolo, Margui- Wandala, Extreme North Province, Cameroon, coll. Wolfgang Böhme, 14–17 February 1974), we refrain from describing this species formally. ZFMK 15171 is a dark-coloured subadult terrapin of 9.3 cm straight carapacial length, resembling in gross morphology P. schweinfurthi or dark-coloured P. variabilis . However, unlike P. schweinfurthi , the pectoral scutes of ZFMK 15171 are triangular and do not reach the plastral midseam. Another terrapin from the same source region was only sampled, but not collected (Museum of Zoology, Senckenberg Dresden, Tissue Collection, MTD T 5183, Maroua, Extreme North Province, Cameroon) and is genetically very similar. Our phylogenetic analyses of mtDNA sequences place candidate species A in the well-supported northern clade of Pelomedusa ( Fig. 1 ). Therein, it is best understood as having a basal position.

Pelomedusa candidate species A differs from all other Pelomedusa species by the presence of guanine (G) instead of cytosine (C) at position 212, by the presence of thymine (T) instead of cytosine (C) at position 222, by the presence of cytosine (C) instead of thymine (T) or adenine (A) at position 302, by the presence of cytosine (C) instead of adenine (A) or guanine (G) at position 325, by the presence of thymine (T) instead of adenine (A) or guanine (G) at position 343, and by the presence of adenine (A) instead of cytosine (C) or thymine (T) at position 345 of the 360-bp-long reference alignment of the 12S rRNA gene (Supporting Information). In addition, Pelomedusa candidate species A differs from all species except possibly P. gehafie and P. kobe by the presence of thymine (T) instead of cytosine (C) at position 50 and by the presence of thymine (T) instead of adenine (A) or cytosine (C) at position 65 (character states in P. gehafie and P. kobe unknown).

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).