Description
In this moderately small species of Hyloxalus males have snout-vent lengths to 24.1 mm and females to 24.8 mm. The discs on the fingers and toes are not or only slightly expanded; Fingers I and II are equal in length, and Finger III is not swollen in males. Lateral fringes are present on the fingers and toes; the outer tarsal fold weak or absent, and the inner tarsal fold is curved on the distal third of the tarsus. The toes are about one-third webbed. The dorsum is pale olive to brown. Dorsolateral stripes and ventrolateral stripes are absent; a pale yellow to tan oblique lateral stripe usually is narrowly bordered by dark brown or black. The gular-chest region is creamy yellow with pair of gray marks; the abdomen varies from dull white to creamy yellow with gray mottling. The iris is grayish brown. A median lingual process is absent, and the testes are white (Edwards 1971).

A tadpole in Stage 34 has a body length of 10.8 mm and a total length of 32.5 mm; the body is ovoid and much wider than high. The snout is bluntly rounded in dorsal view and in profile; the large eyes are situated dorsally, directed dorsolaterally, and not visible from below. The spiracle is sinistral; the tube is short and attached to the body throughout its length. The spiracular opening is directed posterodorsally well below midline at about midlength of the body. The cloacal tube is dextral, short, and attached to ventral fin. The caudal musculature is robust, equal 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 three-fourths 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 two thirds the length of the tail. The oral disc is directed anteroventrally. The median half of the anterior labium is 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 moderately robust and coarsely serrate; the anterior sheath is in the form of a broad arch, and the posterior sheath is broadly V-shaped. The labial tooth row formula is 2(1)/3; A2 is slightly longer than the other rows. In life, the body is olive gray and the tail is yellow proximally, becoming more orange distally, flecked with gray. In preservative, the dorsum and sides of the body are brown, and the belly is translucent gray; caudal musculature is pale creamy tan with brown flecks, and the caudal musculature is translucent with brown flecks.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Ecuador, Peru

View distribution map in BerkeleyMapper.

The species occurs in the Cordillera Occidental and in inter-Andean basins in southern Ecuador and in the Cordillera Occidental and Cordillera de Huancabamba in northern Peru. Its elevational range is 710–2760 m, and it occurs along streams in thorn forest, dry forest, montane dry forest, and humid montane forest. The distribution of Hyloxalus elachyhistus is parapatric to the distribution of H. infraguttatus on the Pacific lowlands of Ecuador and to the distributions of H. anthracinus and H. vertebralis in the inter-Andean basins in southern Ecuador. At elevations of 1920–2590 m on the western slopes of the Cordillera de Huancabamba in Peru, H. elachyhistus occurs sympatrically with H. sylvaticus, and at Cutervo, Departamento de Cajamarca, Peru, it occurs sympatrically with H. pulcherrimus.

Life History, Abundance, Activity, and Special Behaviors
Males are known to attend egg clutches, and both sexes have been reported to transport 5–14 tadpoles having body lengths of 3.3–7.4 mm and total lengths of 9.8–17.4 mm. Free-swimming tadpoles have been found in pools in streams.

References

Coloma, L. A. (1995). Ecuadorian Frogs of the Genus Colostethus (Anura: Dendrobatidae). Museum of Natural History, University of Kansas, Lawrence, Kansas.

Duellman, W. E. (2004). ''Frogs of the genus Colostethus (Anura; Dendrobatidae) in the Andes of northern Peru.'' Scientific Papers of the Natural History Museum, University of Kansas, 35, 1-49.

Edwards, S. R. (1971). ''Taxonomic notes on South American Colostethus with descriptions of two new species.'' Proceedings of the Biological Society of Washington, 84, 147–162.

Species Account Citation: AmphibiaWeb 2007 Hyloxalus elachyhistus <https://amphibiaweb.org/species/1558> University of California, Berkeley, CA, USA. Accessed Nov 14, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 14 Nov 2024.

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