Comprehensive DescriptionRead full entry
In this small species of Hyloxalus males attain a snout-vent length of 19.1 mm and females reach 20.5 mm. The discs on the fingers and toes are expanded, with those on the fingers about half again the width of the penultimate phalanx and those on the toes about twice the width of the penultimate phalanx. Finger I is longer than Finger II, and Finger III is not swollen in males. Lateral fringes are absent on the fingers and toes; outer and inner tarsal folds are absent, but a low, indistinct outer tarsal tubercle is present. Webbing is absent between the toes. Yellowish tan dorsolateral stripes are distinct on the head and diffuse on the body; pale oblique lateral stripes are diffuse and present only in the groin; ventrolateral stripes are absent. The dorsum is brown. The flanks are creamy tan with irregular brown spots, and the sides of the head are dark brown above and dull yellow below. The dorsal surfaces of the upper arms are dull yellow, and the dorsal surfaces of the digital scutes are gray, The belly is creamy yellow with a greenish tint, and the ventral surfaces of the limbs are dull yellow. In males, the throat and chest are brown. The iris is coppery bronze with a median horizontal dark brown streak. A median lingual process is absent. The testes are white.
A tadpole in Stage 34 has a body length of 10.0 mm and a total length of 25.3 mm; the body is ovoid, wider than high. The snout is rounded in dorsal view and in profile. and the moderately large eyes are situated dorsally, directed dorsolaterally, and not visible from below. The spiracle is sinistral, with the tube being short and attached to the body throughout its length. The spiracular opening is directed posteriorly just below the midline at about the midlength of the body. The cloacal tube is dextral, short, cone-shaped, and attached to the ventral fin. Caudal musculature is robust, equal in height throughout the proximal one-third of the tail, and gradually diminishes to a pointed tip. The dorsal fin originates on the caudal musculature, is highest at about two-thirds the length of the tail, and gradually diminishes to an acutely rounded tip. The ventral fin originates on the body and is highest at about three-fifths the length of the tail. The oral disc is directed anteroventrally, with the median half of anterior labium being bare; elsewhere the labia bear a single row of moderately long, pointed marginal papillae. The labia have shallow lateral folds. Submarginal papillae are absent. The jaw sheaths are slender and finely serrate. The anterior sheath is in the form of a broad arch, while the posterior sheath is broadly V-shaped. The labial tooth row formula is 2(1)/3, with row A2 slightly longer than the other rows. In life, the body and tail are gray. In preservative, the dorsum and sides of the body are brown, the belly is cream, the caudal musculature is pale creamy tan with small, irregular brown spots, and the caudal fins are translucent with brown spots; guanophores are scattered on the body and tail.
This species was transferred to the genus Hyloxalus from the genus Allobates by Santos et al. (2009).