Pentonyx capensis Duméril & Bibron, 1835

Fritz, Uwe, Petzold, Alice, Kehlmaier, Christian, Kindler, Carolin, Campbell, Patrick, Hofmeyr, Margaretha D. & Branch, William R., 2014, Disentangling the Pelomedusa complex using type specimens and historical DNA (Testudines: Pelomedusidae), Zootaxa 3795 (5), pp. 501-522 : 510

Pentonyx capensis Duméril & Bibron, 1835

Based on all Pelomedusa specimens present in the collection of the Paris Museum upon the time of the species description, Duméril & Bibron (1835: pp. 390–394) erected Pentonyx capensis . The series of syntypes comprised helmeted terrapins from the eponymous South African Cape Region and from Madagascar, but also the holotype of Emys olivacea from Senegal, which was considered by Duméril & Bibron to represent merely a juvenile Pentonyx capensis . We examined one of the syntypes, MNHN 9506 originating from “Le Cap”, and were allowed to extract tissue for genetic investigation. MNHN 9506 is an adult mounted male in good condition with a straight carapacial length of 23.45 cm ( Fig. 4 ).

Mertens (1937: p. 139) restricted the type locality of Pentonyx capensis to the Cape of Good Hope. However, because no lectotype was designated this action was invalid (cf. ICZN 1999: Art. 76). Nevertheless, later authors identified Pentonyx capensis implicitly or explicitly with the nominotypical subspecies of the helmeted terrapin, if the species was treated as polytypic ( Mertens 1937; Loveridge 1941; Bour 1986; Ernst & Barbour 1989; Iverson 1992). To stabilize this usage, we designate herewith MNHN 9506 as lectotype of Pentonyx capensis .

For the lectotype, mtDNA fragments of all three marker genes could be sequenced ( Table 2 ). In phylogenetic analyses ( Fig. 1 ), the concatenated sequences of MNHN 9506 are embedded within other South African sequences representing lineage IX sensu Vargas-Ramírez et al. (2010). Thus, if lineage IX should be deemed taxonomically distinct, Pentonyx capensis Duméril & Bibron, 1835 would become a subjective junior synonym of Testudo galeata Schoepff, 1792 .

Figures

FIGURE 1. Maximum Likelihood tree for Pelomedusa, based on 1848 bp of mitochondrial DNA (12S, cyt b, ND4+tRNAs), rooted with Pelusios sinuatus. The tree topology completely matches the one inferred by Bayesian analyses. Numbers along nodes indicate bootstrap support and Bayesian posterior probabilities greater than 50 or 0.95, respectively (not shown for some terminal clades with short branches). Sample codes are voucher numbers; see Table S1 for explanation. Name-bearing types (red) and paralectotypes or topotypic samples (blue) highlighted. On the right, mitochondrial lineages of Vargas-Ramírez et al. (2010) indicated. No topotypic material of Pelomedusa galeata orangensis Hewitt, 1935 could be sequenced. However, the lost holotype is thought to come from the vicinity of Kimberley (South Africa) and all South African samples belong to lineage IX, so it can be concluded that Pelomedusa galeata orangensis represents the same lineage. Inset: Helmeted terrapin from the Addo Elephant National Park, South Africa. Photo: M. Gregorič.

FIGURE 4. Dorsal and ventral view of the lectotype of Pentonyx capensis Duméril & Bibron, 1835 (MNHN 9506, male, straight carapacial length 23.45 cm). Scale bar, 3 cm. Photos: M.D. Hofmeyr.