Atelopus halihelos Peters 1973

Atelopus halihelos

Atelopus [species].—Rivero, 1968:21.

HOLOTYPE.—AMNH 16716, male, from Ecuador, Morona-Santiago Province, Cordillera Cutucú, collected by E. Feyer, March 1921.

DIAGNOSIS.—A member of the ignescens group, although limbs are more slender than other species; most similar to nepiozomus, from which it differs in having an almost indistinct first digit on the forefoot and in coloration, particularly in the presence of a light whitish patch below the anus, in contrast to the dark “diaper” of nepiozomus.

DESCRIPTION.—Snout from above with rounded point, distinct angle in canthus rostralis at nostril; snout, canthus, and eyelid fleshy and raised, with either fleshy ridge or row of raised pustules from corner of eye along dorsolateral margin of head. Dorsum of head flat, with scattered, low, glandular pustules. Snout from side protrusive, pointed, extending well beyond upper lip and lower jaw; nostril lateral, below fleshy area of canthus, at top of rounded prominence. Loreal region flat or slightly concave; eye overhung by flap formed of fleshy area, flap has free edge and can be lifted away from the eyelid; upper lip swollen. Temporal region with low, glandular pustules, which may bear pointed spicules in either sex. Dorsum and sides of body smooth, with many low, rounded, scattered warts. Ventral surfaces may be either comparatively smooth or with flattened, indistinct glandular patches separated by wrinkles and folds.

Forelimb slender in females, shorter and more muscular in males, particularly in the forearm. When limb is carried along body, digit tips reach beyond posterior margin of thigh. Dorsal and lateral surfaces of limb covered with warts, more prominent in males than in females. Hand with fleshy webbing, first digit almost entirely enclosed, other digits free. Males with keratinized pad on dorsum of first digit, no horny excrescences on second digit. Sole of forefoot smooth or with few low pustules; plantar tubercle weak, defined by absence of pigment in area.

Hind limb long, slender, covered dorsally and laterally with low warts; tibiotarsal articulation reaches to area between eye and end of head when leg is carried forward along body; heels touch or are barely separated when tibiofibulae are parallel to femora at right angles to body. Webbing thick but not heavily fleshy, extending to tips of all but fourth digit, incised between all digits except first and second; only tip of first digit free of web. Sole almost entirely smooth, subarticular tubercles usually present, but low and often indistinct; outer metatarsal tubercle fairly prominent, distinct; inner metatarsal tubercle larger than outer, but low and indistinct.

COLOR IN ALCOHOL.—Entire body and limbs light brown, with small, scattered, irregular dark brown or blackish spots on all surfaces. Ventral area of thighs and belly immediately below anus very light colored, often whitish, without spots.

HOLOTYPE.—This specimen conforms with the description given above for the species in those characteristics for which no variation is mentioned. In the case of variable characters, it has them as follows: a row of raised pustules along dorsolateral margin of head behind eye; loreal region slightly concave. Warts in temporal region do not bear spicules. Chest and throat with low, indistinct pustules. Heel carried forward along body reaches temporal region; heels do not touch when tibiofibulae are parallel to femora. Soles of both fore and hind foot with few indistinct tubercles, subarticular tubercles on hind foot slightly more prominent. Measurements of type (in millimeters): snout to vent: 25.3; snout to end of coccyx: 23.4; knee to knee: 20.3; tibiofibula: 9.8; head length: 7.8; head width: 7.2; eye diameter: 2.6; snout to eye: 4.0; interorbital distance: 2.6; width of eyelid: 2.2.

Atelopus halihelos, the Morona-Santiago stubfoot toad, is a species of toad in the family Bufonidae endemic to Ecuador. Its natural habitats are subtropical or tropical moist montane forests and rivers. It is threatened by habitat loss.