Adult male Duellmanohyla ignicolor have a snout-vent length of 26.3 - 30.0 mm. The snout, when viewed from the side, is square, and when viewed from above, is rounded. The top of its head is flat. The corners of its eyes are distinct, and the region between its eye and nostril is somewhat concave. It has protruding nostrils, and the region between its nostrils is flat. Its tympana are ovoid, and a skin fold extending from the rear corner of its eye to the forelimb insertion covers the upper edges of the tympana. The anterior region of the chin is thick and glandular. The skin on its throat and underside are granular, whereas the skin on its limbs is fairly smooth. The forelimbs are fairly robust and have a skin fold around the wrist. The first finger is somewhat enlarged and lacks horny nuptial pads, and its second and fourth fingers are of equal length. There is no webbing between the first and second fingers, whereas the rest of the fingers only show rudimentary webbing. It has round subarticular tubercles, of which none are split in two. Its inner metatarsal tubercle is big, flattened, and ovoid, and its outer metatarsal tubercle is triangular. The lengths of its toes are as follows from shortest to longest: 1 - 2 - 5 - 3 - 4. It has smaller discs on its toes than on its fingers. The cloaca lacks flaps, and lies adjacent to two large tubercles underneath, which are flanked by two smaller tubercles on the sides. Thick glands run down from its arms to the groin, which are partially separated medially at the underside of its chest (Duellman 1961, Duellman 1963).
Duellmanohyla ignicolor is similar to D. schmidtorum in appearance, but it can be differentiated as it has smaller tympana, a squarer snout, less toe webbing, the region between its nostrils is flattened instead of indented, and it lacks white stripes on its sides. Both of these species can be differentiated from other Duellmanohyla species as they lack both a tarsal fold and horny nuptial pads in males that breed. Duellmanohyla ignicolor also resembles other sympatric frog species in other genera, but these other frog species can differentiated as follows: Bromeliohyla dendroscarta has a rounder snout and a yellow back; Ptychohyla erythromma has a rounder snout, green back, white thighs, and red eyes; Plectrohyla hazelae has a tarsal fold, a green back, and a black line on the corners of if its eyes; and Ptychohyla leonhardschultzei has a tarsal fold, a brown back, black and white thighs, and horny nuptial pads in males that breed (Duellman 1961, Duellman 1963).
In life, the back is green, whereas the underside is a faint yellowish cream color. The front and back surfaces of its thighs, the undersides of its shins, the front sides of its tarsi, and the upper surfaces of its first three toes towards the center are all red. The iris is pale and gold (Duellman 1961).
In alcohol, the back is light brown and interspersed with non-uniform dark brown markings. The chest and chin are spotted black. The backsides of its limbs are brown with darker brown bars that run across it. The surface of the thighs towards the rear is creamy and speckled brown, and its glandular regions are orange and brown. The undersides of its hindlimbs and first toes are cream-colored, whereas the undersides of both its toes and feet are brown (Duellman 1961).
There is a lot of variation within the species. Some individuals have heart-shaped tongues, while others have notched tongues. Split tubercles may be present on one hand only or on both hands. The chin gland is either faint or very pronounced, as are glands on the sides of its ventral surface. All individuals have a white anal stripe, though this may either be composed of a narrow line or many white specks. The density of black speckling on the chin is highly variable. The colors of the thighs and groin may be red, orange-red, or even brownish red (Duellman, 1963).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Mexico
Duellmanohyla ignicolor lives in mountain streams of cloud forests. The species is endemic to Mexico. It is found in Oaxaca, Mexico, in the lower northern slopes of Sierra de Juarez mountain range, at 600 - 1850 meters (Delia et al. 2013).
Life History, Abundance, Activity, and Special Behaviors
Males of this species call from trees and bushes near the ponds in which they breed. Breeding takes place in the summer and most likely during the rest of the year as well. The call is composed of 3 - 13 low-pitched notes, each lasting about 0.08 seconds and sounding like “raa-raa-raa.” The dominant frequency is 2100 Hz for the short section of calls 3150 Hz for the long sections (Delia et al. 2013, Duellman 1963).
Since the species inhabits cloud forests, it requires humidity and a lot of moisture. It also requires fresh water streams for breeding. Tadpoles of this species live in shallow pools of the streams and use their mouthparts to hold onto rocks and pebbles on the floor of the streams for protection (Duellman 1963).
Trends and Threats
In the last decade, there has been a significant downward trend in population numbers for Duellmanohyla ignicolor. In the summer of 1970, the average number of individuals found by researchers was 13.5 compared to zero individuals found in June 2007. This trend can be attributed to a number of factors, especially general habitat loss and the introduction of disease (Santos-Barrera et al. 2004). In 2000, 13 tadpoles were found and subsequent formation of keratinized mouthparts in some tadpoles strongly indicates that chytridiomycosis is also responsible for endangering this species (Delia et al. 2013, Lips et al. 2004, Santos-Barrera et al. 2004).
No conservation actions have been elicited towards this species besides obtaining protection under Mexican Law. Due to the fact that no designated area in their limited region is under protection, a sense of urgency has been established on the importance of creating ex-situ populations (Santos-Barrera et al. 2004).
Possible reasons for amphibian decline
General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Drainage of habitat
Subtle changes to necessary specialized habitat
The species authority is: Duellman, W. E. 1961. "Descriptions of Two New Species of Frogs, Genus Ptychohyla. Studies of American Hylid Frogs, V." University of Kansas Publications. Museum of Natural History 13: 349-357.
The species epithet “ignicolor” is the Latin word for “flame-colored” and is descriptive of the red flash coloring found on multiple parts of the frog (Duellman, 1963).
This species was originally classified in 1961 as Ptchyohyla ignicolor, but it has since been placed in the genus Duellmanohyla by Campbell and Smith in 1992. This genus contains eight species: D. chamulae, D. ignicolor, D. lythrodes, D. rufioculis, D. salvavida, D. schmidtorum, D. soralia, and D. uranochroa (Duellman 1963, Faivovich et al. 2005).
Ventrolateral mucous glands are found in breeding males (Faivovich, 2005).
No females have ever been found (Duellman 1963).
Delia, J. R. J., Whitney, J. L., Burkhardt, T. 2013. ''Rediscovery of 'Lost' Treefrogs from the Oaxacan Highlands of Mexico.'' Biodiversity and Conservation 22.6-7: 1405-1414.
Duellman, W. E. 1961. ''Descriptions of Two New Species of Frogs, Genus Ptychohyla. Studies of American Hylid Frogs, V.'' University of Kansas Publications. Museum of Natural History 13: 349-357.
Duellman, W. E. 1963. ''A Review of the Middle American Tree Frogs of the Genus Ptychohyla.'' University of Kansas Publications. Museum of Natural History 15.7: 297-349.
Faivovich, J., Haddad, C. F. B., Garcia, P. C. A., Frost, D. R., Campbell, J. A., Wheeler, W. C. (2005). ''Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision.'' Bulletin of the American Museum of Natural History, (294), 1-240.
Lips, K. R., Mendelson, J. R. III, Munoz-Alonso, A., Canseco-Marquez, L. and Mulcahy, D.G. (2004). ''Amphibian population declines in montane southern Mexico: resurveys of historical localities.'' Biological Conservation, 119, 555-564.
Santos-Barrera, G., Alonso, A. M., Canseco-Marquez, L. 2004. ''Duellmanohyla ignicolor.'' The IUCN Red List of Threatened Species. Version 2014.3. http://www.iucnredlist.org/details/full/55308/0.
Written by Haley Martin, Isabella Fenstermaker, Sara Remmes (hmmartin AT ucdavis.edu, irfenstermaker AT ucdavis.edu, seremmes AT ucdavis.edu), University of California, Davis
First submitted 2015-06-11
Edited by Gordon Lau and Ann T. Chang (2017-08-13)
Species Account Citation: AmphibiaWeb 2017 Duellmanohyla ignicolor: Sierra Juarez Brook Frog <http://amphibiaweb.org/species/688> University of California, Berkeley, CA, USA. Accessed Oct 16, 2017.
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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 Oct 2017.
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