Ptychadena christyi (Boulenger, 1919)

Fig. 10E.

Area: Bechuchuu, Yalokole, Yetee.

Season/survey: Wet (Nov 2018), dry (Aug 2019).

Material: CSB:Herp: RNBK 636, 637, 664, 720; IVB-H-CD 18306.

Comments: This species is very poorly known and is somewhat enigmatic because some other species of Ptychadena have been misidentified as P. christyi. Here, we probably show the first published photograph of this species, as the photographed frog published by Noble (1924) does not conform to the morphology of the types of P. christyi. The frog in that figure (Noble 1924) resembles P. longirostris (Peters, 1870) from West Africa, which can indicate either a substantial range extension of this species or that a similar species has remained overlooked in northeastern DRC. Ptychadena christyi was described from “Madié (Ituri)” [= Medje, Haut-Uélé] based on three males and one female (Boulenger 1919). One male syntype is located in BMNH (1947.2.2.59; formerly 1919.8.16.20); and two male and one female syntypes, together with one juvenile also marked as a type (although not listed in the original publication), are stored in RMCA (B.324–326: adults; B. 311 juvenile). This species is characterized by its pronounced dorsolateral glandular ridges/folds and usually smooth dorsum, in contrast to most other Ptychadena species which have numerous distinct longitudinal dorsal folds. Some individuals bear additional short irregular dorsal and lateral folds, which are less conspicuous than the two dorsolateral ones. This is probably why P. christyi has sometimes been considered a close relative of, if not conspecific to, P. aequiplicata (Noble 1924). However, these two species are clearly different at first glance (cf. Figs. 10D–E). Zimkus and Larson (2013) suggested that P. christyi may be conspecific with P. perreti. However, this assumption was based on P. perreti from Uganda which was misidentified as “ P. christyi ” (per our own review of the data). Based on the material stored in RMCA and our own field observations, P. christyi is known only from the forested regions of northeastern DRC. The Kokolopori material thus demonstrates a geographic range extension to the south. It is not clear if the species has been reliably recorded from Uganda, despite reports of it from the country. Based on the available data, it seems that many if not all reports of P. christyi from Uganda were misidentifications (see above and accounts for P. aequiplicata and P. perreti). In Kokolopori, we found P. christyi in puddles or pools on muddy roads formed after heavy rains, where they lay eggs. If the pools were near a bush, the frogs jumped out of the pools to hide in the bushes when disturbed. Some individuals were found in the primary forest at Bechuchuu, in a pirogue (dugout canoe) filled with water.