Petropedetes perreti Amiet, 1973

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 : 28-30

Petropedetes perreti Amiet, 1973

Figs. 3 c, 4, 8a, 9a, 10a, 11a, b

Petropedetes perreti Amiet, 1973 , Bull. I.F.A.N. sér. A., 2: 463

Material examined. MHNG 1253.90 (holotype, formerly JLA 71.196) adult male, Cameroon, Mt. Manengouba, Nsoung, 1400-1500 m, 29.III.1971, coll. J.-L. Amiet; MHNG 961.64 (male), Cameroon, Mt. Manengouba, Nsoung, river Medjié, 1957, coll. J.-L. Perret; MHNG 1522.43 (male), Cameroon, Mt. Manengouba, Nsoung, 29.III.1973, coll. J.-L. Perret; SMF 52364 (female), Cameroon, Nkongsamba, 7.II.1955, coll. J.-L. Perret; ZFMK 69212, 69215, 69219, 69221, 69226 (5 males), 69211, 69213-214, 69216- 217, 69223 (6 females), 69232 (tadpole), Cameroon, Mt. Nlonako, above Nguengue, app. 1100–1200 m a.s.l., 23.XI – 6.XII.1998, coll. ALSCO-Expedition; ZFMK 75524, 75526-28 (4 females),75530, 75532 (2 males), Cameroon, Mt. Nlonako, Nguengue, app. 1100 m a.s.l., 18.-21.I.2000, coll. H.-W. Herrmann & A. Schmitz; ZMB 73731 (female), Cameroon, Mt. Manengouba, Manengouba II, app. 1156 m a.s.l., 16.XI.2006, coll. N.L: Gonwouo; ZMB 73732 (male), Cameroon, Mt. Manengouba, Manengouba II, app. 1260 m a.s.l., 17.XI.2006, coll. N.L. Gonwouo; ZMB 73733 (female), Cameroon, Mt. Manengouba, Manengouba II, app. 1260 m a.s.l., 17.XI.2006, coll. N.L. Gonwouo; ZMB 73734 (female), Cameroon, near Nkongsamba, Plot East 0 0 2, app. 1525 m a.s.l., 08.VIII.2008, coll. M.-O. Rödel & N.L. Gonwouo; ZMB 73735 (male), Cameroon, near Nkongsamba, Plot East 0 0 2, app. 1225 m a.s.l., 10.VIII.2008, coll. M.-O. Rödel & N.L. Gonwouo; ZMB 73736 (female), Cameroon, near Nkongsamba, Plot East 0 0 2, app. 1225 m a.s.l., 17.VI.2008, coll. M.-O. Rödel & N.L. Gonwouo; ZMB 73737 (male), Cameroon, Esipa Village, 12.III.2006, coll. N.L. Gonwouo; ZMB 73738 (tadpoles), Cameroon, Mount Manengouba, 10.VIII.2008, mountain stream at 1225 m a.s.l., coll. N.L. Gonwouo & M.-O. Rödel.

Diagnosis. Medium sized Petropedetes with slender body; tympanum distinct, round, smaller or almost equal to eye diameter in males, distinctly smaller in females; white conical tubercles close to vent; characters of breeding males: tympanic papilla present (long and slim), situated in the centre of the tympanum ( Fig. 8 a); forearm hypertrophy very weakly developed; carpal spike present; spinosities on inner side of arms and forearms (none on throat); femoral glands distinct in both sexes; glands of moderate size, elliptic shape; fully webbed ( Fig. 10 a).

Description. Medium sized Petropedetes with slender body; females slightly larger than males (SUL in males: 29.4–42.6 mm, in females 32.2–48.5 mm); mean head width in males about 40% of SUL, in females about 38%; snout rounded in lateral view; canthus rostralis distinct but slightly rounded; loreal region concave; eye diameter about 1.7 times distance eye-nose; nose closer to snout tip than to eye; distinct round tympanum; smaller or almost equal to eye in males, smaller in females (tympanum / eye in males: 0.77–1.06, in females: 0.47–0.71); tympanum encircled with minuscule white warts; tympanic papilla positioned in centre of tympanum; supratympanic fold distinct; fingers slender, with typically T-shaped fingertips; relative length of fingers: III> IV> II> I; manual subarticular tubercles single; manual webbing absent; palmar tubercle and thenar tubercle present, palmar tubercle sometimes indistinct; forearm hypertrophy moderate in males; carpal spikes present in males; spinosities in males on inner side of arms and forearms (not on throat); skin texture heterogeneous on dorsum and flanks; ventral skin smooth; mean femur length in males about 53% of SUL, in females about 51%, mean tibia length in males 58% of SUL, in females 56%; mean foot length in males 75% of SUL in females 73%; upper and lower hind limbs moderate; femoral glands distinct, but flat in both sexes; glands larger and slightly more prominent in males (femoral gland / femur length in males: 0.24–0.41, in females: 0.18–0.28; Fig. 9 a); relative length of toes: IV> III> V> II> I; fully webbed ( Fig. 10 a; in few specimens webbing absent on posteriormost three fourth on the fourth toe [4 (0.75-0.75)], but then skin folds runs parallel to the last phalange to the tip of the toe).

Coloration. Dorsum marbled of brownish or greenish with black parts or more or less uniformly dark; dorsum speckled with white minuscule spots ( Fig. 8 a); iris speckled with gold and green; larger warts on flanks can be coloured brighter than surrounding parts; legs darker than dorsum; belly whitish; throat whitish or marbled with dark; femoral glands with dark marbling; femora above with large dark spots (almost bars), continuing on lower legs; coloration in preservation: dorsum mainly uniform brownish or black with very small white spots; belly yellowish.

Tadpole. The elongated tadpoles have an ovoid, flat, almost pointed body and a very long and muscular tail that exceed the body length by at least three times ( Fig. 3 c); only last third of tail with very narrow hyaline tail fins, the dorsal ones being a bit longer than the ventral ones; eyes very large and positioned almost dorsally ( Fig. 11 b); nostrils positioned slightly closer to the eyes than to the snout-tip; mouth positioned anteroventrally; keratodont formulae in stage 28 tadpoles (N= 5; total length appr. 20 mm) is 3+3//2+2:1; the keratodont formula of one tadpole (ZFMK 69232, Gosner stage 41) slightly differed: 3+3 //1+1:2; upper and lower jaw shaped like a narrow V; spiracle small, not visible in dorsal view; overall dorsal coloration consisted of a greenish brown, beset with minute bluish dots; along the vertebral line short reddish stripes discernible; venter almost uniform whitish. Stage 41 larvae (N= 3) had a body length of 12.7 mm (total length 36 mm) and very long hind legs (20.5 mm).

Natural history. Petropedetes perreti is a forest species ( Herrmann et al. 2005), occurring along mountain streams above 1200 m and reaching altitudes over 1700 m. It is hence an element of Amiet’s orophil fauna ( Amiet 1973). Lamotte et al. (1959) report adults adhering with their bellies and limbs to stones in strong currents. This observation has also been made by Amiet (1975), who additionally found specimens on leaves of plants on the river sides. The clutch is deposited on rock surfaces within the splash zone of rapids and waterfalls, where the tadpoles develop ( Amiet 1973, 1983, 1989). Males are found at night close to the clutch and appear to defend it ( Amiet 1973).

We observed P. p e r re t i at various sites on the eastern flanc of Mount Manengouba between 1200 and 1500 m a.s.l. along fast flowing mountain rivers. Some of these sites were already heavily degraded but still possessed at least some forest on the banks. Adults and juveniles could be observed at night sitting on stones amidst the torrent or some meters away from water (1-2 m above water on tree and palm trunks). One male was observed sitting on a clutch of approximately 84 eggs with white embryos. The clutch was deposited between mosses on a rock in the splash zone of a rapid, approximately 50 cm above the water surface. After being disturbed, the male only moved a few cm from the clutch ( Fig. 11 a). At another locality we observed tadpoles moving and feeding on wet rocks in the splash zone of a waterfall during daytime ( Fig. 11 b). When approaching them, they only jumped away a few centimeters until they were again out of reach. Only when intensively disturbed did they jump into water.

Distribution. Petropedetes perreti is endemic to Cameroon. The species is found on the southern slopes of the Bamiléké Plateau, Mt. Manengouba and Mt. Nlonako ( Fig. 4 ), areas which are characterized by a very high precipitation through the rainy season ( Amiet 1973; Herrmann et al. 2005).

Genetics. The genetic comparison for the uncorrected p-distances of the mitochondrial 16S rRNAfragment (Table 4) gave the following results for Petropedetes perreti : interspecific comparison between P. perreti and all other Central African Petropedetes taxa ranged between 2.84%-10.16%, while there was no intraspecific variation between the included sequences of the P. p e r re t i vouchers (0.00%; N= 6). The lowest interspecific difference has been detected between P. perreti and P. juliawurstnerae sp. nov. ranging between 2.84%-3.59%, but species can be clearly differentiated on the morphological basis alone (see species description of P. juliawurstnerae sp. nov.).

Systematic remarks. Petropedetes perreti is one of to the two species of the genus with fully developed webbing. In contrast, P. euskircheni sp. nov., P. johnstoni , P. parkeri and P. vulpiae sp. nov. show a mere rudiment of web. It can be easily distinguished from P. p a l m i p e s (fully webbed) and P. c a m e ro n e n s i s (halfwebbed) by its bigger and distinct tympanum and the tympanic papilla in males (see Fig. 8 a, 8b, 8d). The most similar species is P. juliawurstnerae sp. nov. (see respective paragraph for distinguishing characters). Lawson (1993) notes the occurrence of P. p e r re t i from the Rumpi Hills in western Cameroon. However, the taxonomic status of these frogs needs confirmation.

Etymology. The species has been named by Amiet (1973) to honour the herpetologist and former curator of herpetology at the Natural History Museum in Geneva Dr. Jean-Luc Perret.

Figures

FIGURE 3. Tadpole morphology (scale bar mouth 1 mm; scale bar habitus 10 mm): a) P. johnstoni (MSNG 50032; Gosner stage: 41; total length: 26.3 mm); b) P. c a m e ro n e n s i s (modified after Boulenger 1906; tadpole with fully developed hind limbs; no scale bar); c) P. p e r re t i (ZMB 73738; Gosner stage: 28; total length: 24.4 mm); d) P. palmipes (modified after Lamotte et al. 1959); change of denticulation: left: early tadpole stage; centre: tadpole with posterior extremities of 10 mm; tadpole habitus (total length: 22 mm).

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 8. Life coloration of Central African Petropedetes with developed webbing: a) Petropedetes perreti (male: Mt. Manengouba, Cameroon; female: Nguengue, Mt. Nlonako, Cameroon), b) P. cameronensis (left: Limbe, Cameroon; right: Rhoko-forest, Nigeria), c) P. juliawurstnerae sp. nov. (male and female: Nyasoso, Mt. Kupe, Cameroon, d) P. palmipes (left male: Monte Alen, Equatorial Guinea; photo: I. de la Riva; right male: Bipindi, Cameroon; photo: H. - W. Herrmann).

FIGURE 9. Relation of femoral gland to femur and shape of femoral gland in Central African Petropedetes with developed webbing: a) Petropedetes perreti (male: ZFMK 69215; female: ZFMK 69211), b) P. cameronensis (male: ZFMK 81616; female: ZFMK 81555), c) P. juliawurstnerae sp. nov. (male: ZFMK 67360; female: ZFMK 68134), d) P. palmipes (male: MHNG 1033.28; female: MHNG 1033.5).

FIGURE 10. Development of webbing of a) Petropedetes perreti (ZFMK 69217), b) P. juliawurstnerae sp. nov. (ZFMK 68170), c) P. cameronensis (ZFMK 81555).

FIGURE 11. Petropedetes perreti: a) male guarding clutch and b) a tadpole (ZMB 73738); both from mountain streams at 1200 - 1500 m a. s. l., Mt. Manengouba, Cameroon.