Hylarana fonensis

Hylarana fonensis (Rödel and Bangoura, 2004)

Common Names

White-lipped Frog (English)

Languages: English

Overview

Distribution

This species is known so far from two localities  in the Simandou Range of south-eastern Guinea: the northeastern flank of the Pic de Fon Forest and the Parc National de Haute Niger (Rödel and Bangoura, 2004).

Author(s): Zimkus, Breda
Rights holder(s): Zimkus, Breda

Etymology

This species is named for the Pic de Fon forest reserve.

Author(s): Zimkus, Breda
Rights holder(s): Zimkus, Breda

Description

Diagnostic Description

H. fonensis is a large, slender frog with pointed a snout,  and it has a very distinct, concave loreal region. H. fonensis’ skin is very rough due to numerous tubercles on almost all dorsal surfaces with a uniform beige-brown back. This species most distinct feature is it’s comparatively broad dorsolateral ridges that stretch from posterior corner of the eye to the groin. Males have huge protruding glands on the upper arms, extensive webbing on the feet andtoe tips that are long, slender, and pointed (Rodel and Bangoura, 2004).

Author(s): Bergmann, Travis
Rights holder(s): Bergmann, Travis

Size

The holotype measures 59.3 mm in snout-vent length, while the paratypes range from 59.8-63.8 mm.

Author(s): Zimkus, Breda
Rights holder(s): Zimkus, Breda

Morphology

The holotype, an adult male in breeding condition, has a head width of 18.4 mm, approximately one third of SVL, and head length of 21.7 mm. The eye diameter is 6.8 mm, slightly smaller than the diameter of the tympanum (7.3 mm). The interorbital distance (6.5 mm) nearly equals the eye diameter; the eye-snout distance is 10.1 mm. The nostril is closer to the snout (3.9 mm) than to eye (5.6 mm). The canthus rostralis distinct and sharply protruding, and the loreal region is concave. A distinct yellowish lip extends posterior to the angle of mouth. The back and head are a uniform beige-brown, densely covered with round tubercles. The surface of the skin is shagreened with larger tubercles present on the back and upper part of flanks and smaller tubercles on the head, eyelids and dorsal part of the yellowish lip, border of the tympanum and loreal region, the dorsolateral ridges, the upper parts of hind legs and upper arm. Lower parts of flanks and extremities are regularly and densely covered with much smaller spinules. The dorsolateral ridges are distinct and protruding, stretching to the groin. The flanks are dark brown to black on the dorsal half,  and the ventral half are marbled in dark grey and yellowish-olive. The arms are nearly a uniform dark olive. There are black glands on anterior part of upper arms (6.5 mm long). The long and thin fingers have very small discs and are without webbing. The finger formula is as follows: 1>2<3>4. Large nuptial pads are present on the external sides of thumbs, almost same colour as rest of the finger. The hind legs are slightly darker than back with indistinct black bars on thighs (5-6) and tibia (2). The femur (29.7 mm) is half of the SVL; the tibia (32.1 mm) is slightly longer than half SVL. The foot, including the longest toe measures 49.1 mm. There is a distinct inner and outer metatarsal tubercle; the outer is much larger and elongated, and the inner one is round. The toes are long and slender with slightly pointed tips that are not enlarged to discs. The webbing formula is as follows: 1 (0), 2 i/e (1-0), 3 i/e (1-0), 4 i/e (1.75), 5 (0). The outer part of toe 5 has a skin fringe covered with spinules. Webbing is dark grey. The ventral surface appears smooth but bears minute spinules; the belly and lower parts of thighs are granular. The throat is dirty dark brown, and there are no traces of vocal sacs. The breast is yellowish brown and belly is beige. Lower parts of the hind legs are yellowish-brown, and the sides have small brown spots.

Author(s): Zimkus, Breda
Rights holder(s): Zimkus, Breda

Comparisons

H. fonensis has a similar appearance to A. albolabris and A. asperrima; however, A. albolabris and A. asperrima males have much darker backs than H. fonensis. In A. albolabris the backs are nearly always coloured with irregular black spots, while in A. asperrima these spots are often present but occasionally might be absent (Rodel and Bangoura, 2004).

Author(s): Bergmann, Travis
Rights holder(s): Bergmann, Travis

Ecology

Habitat and Ecology

H. fonensis occurs in symparty with A. albolabris. H. fonensis has been found in northeastern flank of the Pic de Fon and the Parc National de Haute Niger forest habitat. These parks consist mainly of Guinea savannah, but also include some forest remnants that harbour tropical forest species. It has been suggested that this species might be widespread in the Guinean transition zone between rainforest and humid Guinea savannah (Rodel and Bangoura, 2004).

Author(s): Bergmann, Travis
Rights holder(s): Bergmann, Travis

Taxonomy

  • Amnirana fonensis Rödel and Bangoura, 2004 (synonym)
  • Hydrophylax fonensis — Frost, 2006 (synonym)
  • Hylarana fonensis — Che, Pang, Zhao, Wu, Zhao, and Zhang, 2007 (synonym)

References

Rödel, M-O., & Bangoura M. A. (2004).  A conservation assessment of amphibians in the Forêt Classée du Pic de Fon, Simandou Range, southeastern Republic of Guinea, with the description of a new Amnirana species (Amphibia Anura Ranidae). Tropical Zoology. 17, 201–232.