Pelomedusa gasconi Rochebrune, 1884

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 : 514

Pelomedusa gasconi Rochebrune, 1884

Rochebrune (1884: pp. 25–26; plate 1: figs 1–2) described helmeted terrapins from several sites in Senegal (“Dagana, Saidé, lac de N’Guer, marigot des Maringouins” [the latter meaning mosquito oxbows of N’Gor lake, Dakar, Senegal]) as his new species Pelomedusa gasconi , which was later synonymized by Loveridge (1941: p. 480) with Pelomedusa subrufa olivacea . In accordance with this assignment, Rochebrune’s (1884) plate 1 shows a helmeted terrapin with widely separated pectoral scutes, although Rochbrune explained that this character may be variable (pp. 26–27). According to Angel (in Loveridge 1941: p. 480), there was no type specimen of Pelomedusa gasconi preserved. Loveridge (1941: p. 480) restricted the type locality to Dagana, Senegal, which is invalid without lectotype or neotype designation (cf. ICZN 1999: Art. 76).

The sites of the composed type locality are up to 400 km distant from one another. To restrict the type locality and to associate the name Pelomedusa gasconi Rochebrune, 1884 unambiguously with a genetic lineage of Pelomedusa , we designate in accordance with Article 75 (ICZN 1999) a topotypic specimen from Dakar as its neotype (ZFMK 17076, a subadult female of 11.18 cm straight carapacial length in alcohol; Fig. 6 , bottom). For the neotype, mtDNA sequences are available (see also above under Emys olivacea Schweigger, 1812 ). Thus, the name Pelomedusa gasconi is to be identified with the same genetic lineage as Emys olivacea (lineage III of Vargas- Ramírez et al. 2010; Fig. 1 ) and becomes a subjective junior synonym of the latter name, if lineage III is deemed taxonomically distinct.

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 6. Dorsal and ventral views of the lectotype of Pelomedusa nigra Gray, 1863 (BMNH 1849.1.30.27, adult male, straight carapacial length 16.19 cm; top) and of the neotype of Pelomedusa gasconi Rochebrune, 1884 (ZFMK 17076, subadult female, straight carapacial length 11.18 cm; bottom). Scale bars, 3 cm. Photos: P. Campbell, A. Petzold.