Phrynobatrachus intermedius, Rodel, Boateng, Penner & Hillers, 2009

Rödel, Mark-Oliver, Boateng, Caleb Ofori, Penner, Johannes & Hillers, Annika, 2009, A new cryptic Phrynobatrachus species (Amphibia: Anura: Phrynobatrachidae) from Ghana, West Africa, Zootaxa 1970, pp. 52-62 : 52-62

Phrynobatrachus intermedius sp. nov.

Figs 1–4

Holotype. ZMB 71538 (GB: FJ415751 , field and tissue #: MOR ANK28 ), adult female, primary forest near stream, partly swampy, Ankasa Conservation Area , N 5°16.642', W 02°38.253', Ghana, 2 April 2007, coll. C.O. Boateng & A. Hillers.

Paratype. ZMB 71539 (GB: FJ415752 , field and tissue #: MOR ANK30 ) , subadult female, other data as holotype .

Additional material. ZMB 71540, juvenile, swampy area with slow moving streams, Nini-Suhien National Park , N 05°17.845', W 02°36, spring 2008, coll. C.O. Boateng.

Diagnosis. The genetic results show that the new species belongs to the genus Phrynobatrachus . Morphologically this is visible by the body shape; presence of tarsal tubercle; presence of inner and outer metatarsal tubercle; presence of feebly developed, slightly converging dorsal ridges; lack of parallel dorsal ridges; lack of black spot in the tympanal region; lack of fine medial dorsal skin raphe; neither finger nor toe tips heart shaped nor expanded to discs.

Medium-sized, compact Phrynobatrachus , characterized by combination of comparatively smooth back with feebly developed dorsal ridges; triangular face mask, consisting of dark loreal and tympanal region; absence of eyelid cornicle; short and pointed snout; blackish throat with a small number of white spots; breast with blackish vermiculation; and well developed webbing.

Description of the holotype (measures in mm). Adult female with numerous, unripe, small white eggs in the oviducts; typical Phrynobatrachus with oval, compact body shape; snout-urostyle-length: 27.76; short snout, rounded in dorsal and pointed in lateral view; canthus rostralis distinct and sharp; loreal region plain; head-width directly behind the eyes: 9.80; eye-diameter: 3.28; distance eye-nostril: 2.44; distance eye-snout tip: 4.55; nostril closer to snout than to eye; tympanum present but indistinct, tympanum diameter: 2.08, smaller than diameter of eye; femur: 13.77, slightly shorter than tibio-fibulare: 15.99; foot including longest toe: 23.02; hand with large, oval palmar and thenar tubercles; fingers with small roundish subarticular tubercles, no additional tubercles on hands; relative finger length: 1=2>4>3; palmar webbing absent; tarsal tubercle present; large and oval internal and smaller, round external metatarsal tubercle; inner metatarsal tubercle approximately one third of shortest toe length; relative toe length: 1<2<5<3<4; webbing formula: 1 (1), 2 (1- 0.5), 3 (2-1), 4 (2.5), 5 (1); toe and finger tips slightly expanded without forming discs.

Dorsal skin grainy; eyelids smooth; back with inconspicuous dorsal ridges that start behind the eyes on the level of the tympani, converge slightly and end shortly posterior to the bases of the forelegs; no other warts discernible; ventral skin smooth.

Overall coloration of the dorsum reddish-brown, slightly fading towards the belly to a grayish-brown; small bluish spots in the middle of the back, positioned on both sides in line with the dorsal ridges; dorsal parts of forelegs without blackish bars; femur and tibia dorsally with three indistinct dark bars; outer, posterior parts of thighs uniform reddish-brown; anterior part of thighs lighter and slightly mottled with brown; vent in the middle of black triangle that is dorsally bordered by fine white line; very conspicuous dark chocolatebrown to blackish triangular face mask, starting at snout tip and covering loreal and tympanal region; dorsally this mask bordered by fine, irregularly bordered white line; posterior to tympanum the face mask curves down to bases of forelegs, following fine supratympanal ridge; upper and lower mandible slightly darker than face mask and throat, with very few minute white points; throat dark brown with irregular white spots; breast and upper part of belly white with dark brown vermiculation pattern; remainder of belly and ventral part of thighs white to beige; dark color of throat extending to anterior parts of upper arm; lower arm and lower leg with fine darker mottling; color in preservation slightly faint, otherwise not very different to life; dorsal bluish spots in life green.

Variation. Further measures and body relations of type material are summarized in Tables 1 and 2. The non-type specimen differs slightly in the extension of the dark portion of the ventral pattern. The paratype is a subadult female with a uniform brown back, while the juvenile has a clear pair of dorsal spots. Both posses the dark face masks. The paratype has some white spots on the lower arm. Males of this species are so far unknown.

TABLE 2. Morphometric relations of Phrynobatrachus intermedius sp. nov., P. liberiensis and P. plicatus . Given are mean and standard deviation (x ± sd) values; only adult specimens included. For abbreviations see Material and methods. For vouchers’ data see Appendix 1.

Genetics. Both Phrynobatrachus intermedius types were identical in the 560 investigated base pairs of the 16S rRNA gene. Compared to 16 West African and Central African species of the genus Phrynobatrachus , the new species differed by 3.4–16.6% ( Table 3). From the morphologically most similar species, P. liberiensis and P. plicatus , the new species differed by 4.7 ± 0.7 % (mean ± standard deviation; N= 15) and 10.9 ± 0.0 % (N= 7), respectively. P. liberiensis from the P. intermedius type locality, the Ankasa Resource Reserve, were genetically more distant to the new species (5.8 ± 0.0 %, N= 3) than specimens from other parts of West Africa (4.4 ± 0.5 %, N= 12; Table 3 and Appendix 1).

Natural History. All specimens of the new species were collected in swampy parts of primary rainforest in the Ankasa Reserve. This reserve is divided into two: the Ankasa Resource Reserve and the Nini-Suhien National Park, collectively called the Ankasa Conservation Area. The two types have been collected in the swamps of the Resource Reserve, where the new species occurs, amongst other frog species, in sympatry with P. liberiensis and P. plicatus . The juvenile originates from the National Park where it was collected in a swampy primary forest with slow moving streams. At this site P. ghanensis was very abundant. Unfortunately no other data on the natural history of this species are available. For more details concerning Ankasa Reserve see Rödel et al. (2005b).

Distribution. Phrynobatrachus intermedius is only known from two sites in the Ankasa Reserve in southwestern Ghana ( Fig. 5).

Etymology. The species’ name is an adjective chosen because of the unique mixture of morphological similarities of the new species to P. liberiensis and P. plicatus , making it morphologically intermediate to these two species.