Petropedetes parkeri Amiet, 1983

Barej, Michael F., Rödel, Mark-Oliver, Gonwouo, Legrand Nono, Pauwels, Olivier S. G., Böhme, Wolfgang & Schmitz, Andreas, 2010, Review of the genus Petropedetes Reichenow, 1874 in Central Africa with the description of three new species (Amphibia: Anura: Petropedetidae), Zootaxa 2340, pp. 1-49 : 17-22

Petropedetes parkeri Amiet, 1983

Figs. 1 c, 2c, 4, 7a, 7b, 7f

Material examined. BM 1936.3.4.124 (holotype) adult male, Cameroon, Mamfe region, Atolo, Assumbo, 12.IV.1933, coll. I. Sanderson; BM 1936.3.4.123 (male), Cameroon, Mamfe; BM 1936.3.4.127 (female), 1936.3.4.136 (male), Cameroon, Bachor II; 1936.3.4.128 (female), 1936.3.4.131 (male), Cameroon, Bashau, 1932-1933, coll. I. Sanderson; MHNG 961.66 (male, formerly BM 1936.3.4.133), Cameroon, Mamfe Division, Bashau, 10.III.1933, coll. I. Sanderson; PEM A 9123-9124 (2 males), A 9126 (male), A 9127 (female), Cameroon, Nguti, 15.VII.1996, coll. L. Minter; PEM A 9125 (male), A 9128 (male), 5. & 9.VII.1996, other data as A 9123; ZFMK 61337-338 (2 females), 61342 (male), Cameroon, Ekundu-Kundu, 3-27.II.1989, coll. M.T. O’Shea; ZFMK 87702 (female), Cameroon, Mamfe region, near Amebishu, app. 720 m a.s.l., 14.IX.2007, coll. J.A.M. Wurstner & M.F. Barej; ZMB 73739 (female), Nigeria, Okwangwo, app. 900 m a.s.l., 15.IV.2004, coll. M. Gartshore.

Problematic material (see systematic remarks). IRSNB-KBIN 13.842 (female), Gabon, Estuaire Province, Kango Department, 15 north of Alen-Nkoma, right of route L107, 2004, coll. O.S.G. Pauwels; IRSNB-KBIN 14.941 (female), Gabon, Province du Woleu-Ntem, Tchimbélé, app. 469 m a.s.l., 20.VI.2001, coll. O.S.G. Pauwels; MHNG 1521.60 (male), 1521.61 (female), 1521.64-65 (2 females), Cameroon, Bafoussam, Bangwa, 7.IV.1973, coll. J.-L. Perret; MHNG 1521.70-71 (2 males), Cameroon, Yaoundé, Mt. Kala, X.1972, coll. J.-L. Perret; MHNG 1521.78 (male), Cameroon, Dschang, Falaise de Mbos, 25.XI.1972, coll. J.-L. Perret; ZFMK 73209 (female), 73210 (male), Gabon, Barrage de Tchimbélé, coll. V. Gossmann & S. Lötters; ZMB 73892 (female), same data as IRSNB-KBIN 14.941.

Diagnosis. Large sized Petropedetes ; robust body shape; tympanum round, larger than eye diameter in males, smaller in females; characters of breeding males: tympanic papilla present (broad and fleshy); papilla close to the upper border of the tympanum; forearm hypertrophy strongly developed in males; carpal spike present; tegumental spinosities well developed on throat, forearms, scattered on flanks and dorsum; femoral glands small, coloured similar to limb, shifted slightly to the posterior side of the leg; webbing rudimentary.

Description. Large sized Petropedetes with robust body; males distinctly larger than females (SUL in males: 38.0– 74.3 mm, in females: 34.1–61.3 mm); mean head width in males about 44% of SUL, in females about 42%; snout in lateral view short, rounded; canthus rostralis slightly rounded but distinct; loreal region concave; eye diameter about 1.3 times eye-narial distance; nose closer to snout-tip than to eye; distinct tympanum, usually larger than eye in males, always smaller in females (tympanum / eye in males: 0.73-1.39, in females: 0.60–0.89; the lowest value of 0.73 in males measured in the smallest specimen, second smallest value: 0.92; tympanic papilla closer to upper border than centre of tympanum; papilla broad and fleshy with oval basis; supratympanic fold distinct; fingers slender, with typically T-shaped fingertips; relative length of fingers: III> IV> II> I; manual subarticular tubercles single; palmar tubercle and thenar tubercle present, palmar tubercle sometimes indistinct; forearm hypertrophy strongly developed in males; carpal spike present in males; tegumental spinosities well developed on throat, forearms, scattered on flanks and dorsum in males; dorsal tegument with smaller warts than flanks; few larger, elongated warts on dorsum; ventral skin smooth; femora long, mean femur length in males 50% of SUL, in females 51%; mean foot length in both sexes 74% of SUL; upper hind limbs of moderate width, lower hind limbs slender; femoral glands small in both sexes, slightly bigger in males (femoral gland / femur in males: 0.18–0.27, in females: 0.16–0.22); relative length of toes: IV> III> V> II> I; webbing rudimentary: 1 (1) 2 (1-1) or 2 (1.25-1) 3 (2-2) 4 (3-3) 5 (2).

Coloration. Dorsum and flanks olive or brownish and dark marbled with diffuse brown-olive spots ( Fig. 1 c); throat dirty whitish; belly whitish, slightly translucent; throat can be darker than belly; femora and lower legs with large darker spots, darker spots divided by thin bright coloured transversal bars; ventral surfaces of limbs of the same coloration as belly, pale greenish; iris golden with white-green shades; femoral glands coloured as hind limbs, pale orange or greenish. Coloration in preservation: similar as in life; dorsum uniform brown; belly whitish, with minuscule speckles (less dense than in former species, only recognizable under microscope); throat dirty whitish or pale brown.

Natural history. After the first work on the ecology of the species by Sanderson (1936, referred to as P. johnstoni ), additional data have been gathered by Amiet. However, some observations by Amiet (e.g. 1975, 1983, 1986) are based on populations of “ P. parkeri ” from Mt. Kala, the Bamiléké Plateau and the region of Nkongsamba. The taxonomic status of these populations at present is not clear (see below). Sanderson (1936) calls this species arboreal, because he found them on lower, broadened leafs, in shade. The breeding season is said to take place in the rainy season ( Parker 1936; referred to as P. johnstoni ). The species has been found on wet, mossy rocks in the forest; the large rocks were crossed by runlets ( Fig. 7 a). According to Sanderson (1936) the adults aggregate in the breeding season on humid rocky surfaces in rough areas with torrent water, while they live in the forest on leaves outside the breeding season.

The advertisement call of P. p a r k e r i has been published by Narins et al. (2001). Narins et al. (2001) describe a part of the courtship behaviour, including the female striking the male’s head with her foreleg during amplexus. These authors speculate that this behaviour is connected with secretion of glands in the male tympanal papilla. The small eggs are deposited at the beginning of the rainy season on surfaces of stones within the splash zone. Metamorphosis in P. parkeri is finished before the end of the rains or at the beginning of the dry season ( Parker 1936).

Petropedetes parkeri shows, in contrast to other members of the genus, a reversed sexual size dimorphism ( Amiet 1983). The state that males grow larger than females is rare and occurs only in about 10% of amphibians ( Shine 1979). Most often this is connected to some kind of territoriality or male parental care. However, Sanderson (1936) notes the laceration of non-breeding males in the gular region and assumed relics of the previous breeding seasons. This could be regarded as an outcome of territorial behaviour. Further respective data are however lacking. This species appears to live in forests. Some specimens of P. aff. parkeri from Gabon (see below, Fig. 7 f) have been collected during the day in a gallery forest. P. aff. parkeri is called “barking frog” by locals in western Gabon (V. Gossmann pers. comm.).

Distribution. We can only assign populations from western Cameroon and eastern Nigeria to P. parkeri with certainty ( Fig. 4 ). At these locations species inhabit altitudes below 1000 m.

Genetics. The genetic comparison for the uncorrected p-distances of the mitochondrial 16S rRNAfragment (Table 4) gave the following results for Petropedetes parkeri : interspecific comparison between P. parkeri and all other Central African Petropedetes taxa ranged between 5.94%-12.39%, while the intraspecific variation within P. p a r k e r i was much lower at 0.00%-0.22% (N= 4).

Systematic remarks. Petropedetes parkeri has long been confused with “ P. newtonii ” (described herein as P. v u l p i a e sp. nov.) and P. johnstoni (Gartshore 1994) . Amiet (1983) first recognizes that the description of the species’ habitat by Parker (1936) and Sanderson (1936) do not fit the circumstances of the description by Boulenger (1900). He subsequently described this species using distinct morphological characters. P. parkeri and P. euskircheni sp. nov. are the two largest members of the genus. The fleshy papilla in both species has an oval basis, while it is rounder in the remaining species. P. parkeri is only rudimentary-webbed and therefore easily distinguishable from more fully webbed species ( P. palmipes and P. p e r re t i, both fully webbed; P. cameronensis and P. juliawurstnerae sp. nov., both half-webbed). Moreover, the presence of a distinct tympanum and a tympanal papilla seperates P. parkeri from P. cameronensis and P. palmipes , which lack these characters. The size of the femoral gland distinguishes P. parkeri from P. vulpiae sp. nov. and P. johnstoni , which possess much larger ones. Due to a similar appearance, P. p a r k e r i has been confused with a cryptic species in the past. Distinguishing characters between P. p a r k e r i and P. euskircheni sp. nov. are presented in the description of the new species (see below).

As holotype, Amiet (1983) has chosen a P. parkeri from Atolo, Mamfe region. The paratypes were from localities in the Mamfe region, but also from the “Falaise de Mbos” and Bangwa. He further investigated material from Kala, Léna (Yaoundé region). He regards the species as vocally and morphologically homogenous throughout its discontinuous range, although he mentioned small deviations in the lengths of the femora between western and eastern populations (Mt. Kala, Yaoundé region; Amiet 1983). The type locality at Atolo is located at app. 425 m a.s.l. The overall altitudinal distribution ranges between 400 and 2300 feet (approximately 120-700 m; Parker 1936; Sanderson 1936). Own and unpublished findings confirm sites below 1000 m. The sites are a hill close to Mukwecha (720 m), Okwangwo (900 m) and material collected by Les Minter from Nkwende Hills near Nguti (400 m). Amiet (1978, 1983) instead lists altitudes between 750– 1400 m from Mbakang and Foto-Ndonchwet and doubts localities in very low altitudes from Sanderson (1936) and Parker (1936). The altitudinal range of P. parkeri may overlap with the altitudinal range of P. euskircheni sp. nov. (type locality at about 900 m; see below). Without genetic comparisons, so far the P. parkeri -like populations in Central Cameroon region around Yaoundé and the northern populations of the Manengouba Mountains cannot be assigned with certainty, neither to P. parkeri nor to P. euskircheni sp. nov.

Due to the finding of P. euskircheni sp. nov. not all populations can be irrespectively assigned to a particular taxon. We therefore assign unsure localities within Cameroon (e.g. Mt. Kala), but also specimens from Gabon (e.g. Frétey & Blanc 2001; Lötters et al. 2001) and Equatorial Guinea (de la Riva 1994; Lasso et al. 2002) to P. aff. parkeri ( Fig. 4 ).

Etymology. The species has been named by Amiet (1983) in honour of Mr. Hampton Wildman Parker, former curator of the Natural History Museum, who conducted a meticulous morphological study on specimens from the Sanderson collection.

Figures

FIGURE 1. Life coloration of rudimentary-webbed Central African Petropedetes. a) Petropedetes johnstoni (male and female: Nkoelon, Cameroon), b) P. vulpiae sp. nov. (male and female: Nyasoso, Mt. Kupe, Cameroon), c) P. parkeri (male Nguti, Cameroon; female: Amebishu, Cameroon) d) P. euskircheni sp. nov. (male: Nyasoso, Mt. Kupe, Cameroon; female: Nguengue, Mt. Nlonako, Cameroon).

FIGURE 4. Distribution of known Petropedetes species; compare with text. Specimens from localities marked with an asterisk (*) were not available and are added from literature.

FIGURE 7. Habitat pictures and specimens of uncertain determination: a) Petropedetes parkeri, Mamfe region, Cameroon; b) P. vulpiae sp. nov. biotope, waterfall at Itsila, Gabon – Republic of Congo border; c) P. vulpiae sp. nov., cascade 15 km north of Alen-Nkoma, right of Route L. 107, Kango Department, Estuaire Province, Gabon (photo: J. P. Vande weghe); d) type locality of P. juliawurstnerae sp. nov. and P. euskircheni sp. nov., habitat of P. vulpiae sp. nov., Nyasoso, Mt. Kupe, Cameroon; e) P. vulpiae sp. nov., cascade at Big Massaka, Cameroon; f) P. aff. parkeri, Barrage de Tchimbélé, Gabon (ZFMK 73132; photo: V. Gossmann); g) P. cf. johnstoni near Langoué Bai, Gabon (no voucher; photo: J. P. Vande weghe):