Hyperolius phantasticus ( Boulenger, 1899 )

Badjedjea, Gabriel, Masudi, Franck M., Akaibe, Benjamin Dudu & Gvoždík, Václav, 2022, Amphibians of Kokolopori: an introduction to the amphibian fauna of the Central Congolian Lowland Forests, Democratic Republic of the Congo, Amphibian & Reptile Conservation (e 301) 16 (1), pp. 35-70 : 56

Hyperolius phantasticus ( Boulenger, 1899)

Hyperolius phantasticus boulengeri Laurent, 1943 (new status)

Figs. 8G–H , 9A–B .

Area: Yalokole, Yetee, Yotemankele.

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

Material: CSB:Herp: RNBK 001, 003, 010, 013, 021, 033, 164, 168, 176, 187, 189, 199, 202, 205, 213, 217, 223, 238, 301, 303–305, 307, 308, 330, 337, 356, 357, 359, 363, 368–370, 374, 382, 383, 393, 394, 399, 403, 406, 409, 410, 431, 440, 449, 459, 468–472, 474, 475, 479, 480, 571, 579, 580, 605, 616, 701; IVB-H-CD 18087–18091, 18096–18099, 18110–18116, 18162– 18164, 18191, 18192, 18202, 18203, 18294, 18342– 18346, 18492, 18493, 18508, 18518, 18519, 18523, 18526, 18528.

Comments: Hyperolius phantasticus is distributed from southern Cameroon to western Congo / DRC and to central DRC ( Channing and Rödel 2019), and was described from the present-day continental Equatorial Guinea ( Sánchez-Vialas et al. 2020). It is one of the most abundant anuran species in Kokolopori, usually present along streams and rivers in open or semi-open areas, perching on high herbaceous vegetation and shrubs. Many pairs were found in amplexus during the wet seasons, while no amplectant pairs were found during the dry season. In this region, this species occurs in two color phases as already described by Schiøtz (2006): Phase J ( Fig. 8G ; juveniles/males; Schiøtz 1967) with the predominately light, translucent green dorsal color, unspotted or sprinkled with tiny dark spots, canthal stripes (light or dark) in most specimens, in some individuals continuing behind the eye halfway down the body, venter mostly yellow-green with some blue patches; and Phase F ( Figs. 8H , 9A ; females/female-like males) with the maroon to beige dorsal color, sometimes with small yellow dots, ventral side mostly ink-black suffused with bluish and pinkish tones in dispersed light patches (sometimes concentrated in the center while circum-marginal areas are black). The inflated throat of males is mostly of the blue-green color in both color phases, with the gular disc yellow in Phase J and showing the dorsal maroon color in Phase F. The coloration differs significantly from the holotype of H. phantasticus (female; Boulenger 1899) and the populations of Cameroon and northern Gabon (cf. Amiet 2012; Amiet and Goutte 2017; Dewynter and Frétey 2019), which are characterized by yellow dorsal coloration without spots, only with dark canthal stripes, and the ventral side is ink-black only in the posterior parts ( Amiet 2012; Boulenger 1899). These geographic differences in coloration have already been discussed ( Amiet 2012; Köhler et al. 2005). We therefore propose to resurrect Hyperolius boulengeri Laurent, 1943 [type locality “Flandria (Tshuapa),” DRC; Laurent 1943] at the subspecies level as H. phantasticus boulengeri (new status) to account for geographic variation with the consistent color differentiation and genetic divergence (unpub. data; genetic data to be published elsewhere) of the central Congolian populations. It is possible that this taxon occurs as far west as southern Gabon and southwestern Republic of the Congo as the coloration of H. phantasticus in these regions (cf. Jongsma et al. 2017; Largen and Dowsett-Lemaire 1991) roughly corresponds to individuals from central DRC. However, a phylogeographic study is needed to clarify the distribution range of this taxon and whether it deserves full species status. We have observed that this species is preyed upon by fishing spiders ( Nilus , Pisauridae ), with a male of Phase F found as a prey item in May 2018 ( Badjedjea et al. 2019), and a male of Phase J as a second case in the dry season of August 2019. Interestingly, we observed a certain level of the fluorescent emissions in adult males of Phase J ( Fig. 9B ) upon illumination with a UV light (λ max 395–400 nm), which agrees with the hypothesis of the existence of fluorescence in anurans with greenish-translucent skin ( Taboada et al. 2017a,b). Fluorescence was not observed in males of Phase F.

Figures

Fig. 8. Hyperoliids, Hyperolius. (A) H. cf. cinnamomeoventris, striped morph (male). (B) H. cf. cinnamomeoventris, striped morph (female). (C) H. cf. cinnamomeoventris, hourglass morph (male). (D) H. cf. cinnamomeoventris, hourglass morph (female); note the species-specific red coloration of the inner thighs in both sexes in (C) and (D). (E) H. cf. cinnamomeoventris, hourglass morph (male). (F) H. cf. langi, striped morph, “forma albomarginata” (male). (G) H. phantasticus boulengeri (male, Phase J). (H) H. phantasticus boulengeri (female).

Fig. 9. Hyperoliids, Hyperolius and Hylambates. (A) Hyperolius phantasticus boulengeri (amplectant pair, both sexes in Phase F). (B) H. phantasticus boulengeri under UV light (male, Phase J). (C) H. cf. platyceps, hourglass morph (male). (D) H. cf. platyceps, striped morph, “forma pleurotaenia” (male). (E) H. cf. platyceps, hourglass morph, ventral view (female). (F) H. ocellatus purpurescens (female). (G) Hylambates verrucosus (male). (H) H. verrucosus, ventral view (same specimen as in G).