Description

DESCRIPTION:

Bromeliohyla melacaena is a small and flat frog with a snout-vent length range of 21.8 - 22.6 mm in males and 24.2 - 25.9 mm in females, based on three males and two females. The skin on the dorsal side is smooth while skin on the throat, chin, and ventral surfaces of limbs are granular. The head is wider than the body with a rounded snout, slightly protruding nostrils, large protruding eyes, and a visible tympanum. There is a slight dermal fold present from the back corner of each eye to the base of each front leg, and both sexes lack ventrolateral glands. The limbs are of moderate length and robustness. Males have 7 - 10 spines on thumbs under a swollen pad. The fingers of both sexes have relatively small discs and the webbing is basal between fingers I - II and III - IV. Both males and females have smooth heels that overlap when the legs are folded at right angles to the body. The toe disks are slightly smaller than the finger discs. The cloaca is located near the mid-thigh with a narrow and short cover (McCranie and Castañeda 2006).

DIAGNOSIS:

Bromeliohyla malacaena differs from the genus Ptychohyla by the former having smaller thumb spines, lacking the ventrolateral glands, and being significantly smaller. Bromeliohyla malacaena differs from Isthmohyla zeteki and Isthmohyla picadoi due to the presence of thumb spines in B. malacaena. Bromeliohyla malacaena differs from Bromeliohyla bromeliacia by having less toe webbing, being smaller, and having sexually dimorphic coloration (McCranie and Castañeda 2006). Heavily pigmented gums distinguishes B. dendroscarta from other Bromeliohyla (Taylor 1940).

COLORATION:

In life, male B. malacaena are pale brown with large yellow spots on their snout and dorsal side. The posterior dorsum is translucent with pale green punctuations through which the white bones can be seen. The upper eyelids have small yellow spots. Their thumb spines are black. The dorsal surfaces of the limbs are pale brown except for the posterior surface of the thighs, which are yellowish brown. The ventral surfaces are dirty white except for the thighs, which are yellowish brown. Female B. malacaena are dark brown with a light brown interocular stripe, a yellow-green snout, and pale inner thighs. Both have black spotted orange eyes, pale brown finger and toe discs, and bones visible through the posterior dorsal translucent skin. In preservative, the dorsum continues to be brown with yellow spots in males. Females are plainer and darker brown. All toe pads, throat, and the chin become grey, with the chin having brown punctations on the anterior region. The stomach is distinctly paler in females than in males (McCranie and Castañeda 2006).

VARIATION:

Bromeliohyla melacaena is sexually dimorphic in color (McCranie and Castañeda 2006).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Honduras

View distribution map in BerkeleyMapper.

Bromeliohyla melacaena is found on the mainland of Honduras between the elevations of 1,370 and 1,990 meters. Bromeliohyla melacaena is estimated to exist in an area of 388 square kilometers. The general habitat of B. melacaena is montane pine forest or broadleaf forest with freshwater present, but they have also been observed in coffee plantations as long as there are sufficient bromeliads present (IUCN 2019).

Life History, Abundance, Activity, and Special Behaviors
Bromeliohyla melacaena is believed to be most active at night, and rest in bromeliads during the day. However this species is becoming increasingly rare to find as populations are declining (McCranie and Castañeda 2006, IUCN 2019).

The frogs collected for the species description were found in forested areas around 150 meters away from the nearest freshwater source, and were found in or near bromeliads 1 - 5 m in the canopy during the day. Bromeliohyla melacaena is thought to use bromeliads as shelter for reproduction as males have been seen calling from them and females are often found there (McCranie and Castañeda 2006).

While there are no specific records of calls, it is certain that males call to the females for mating from inside of a bromeliad (McCranie and Castañeda 2006).

There are no specific records of reproduction or tadpole development for this species. However, as a member of the family Hylidae, it can be assumed that this species is ovoviviparous and has tadpoles (Vitt and Caldwell 2014). Other members of the genus breed and deposit eggs in bromeliads (Duellman 1970, Canesco-Marquez et al. 2018)

Trends and Threats
Bromeliohyla melacaena is “Endangered” and experiencing population decline. Anthropogenic threats to the species include urbanization, logging, severe weather such as droughts or flooding, loss of habitat to agriculture (mostly coffee), loss of habitat to human-caused fires, and pollution from insecticides and herbicides. Another potential threat to the species is chytridiomycosis because members of a related species, B. bromeliacia, has previously been recorded as infected. The species can be found in Parque Nacional Cusuco and Reserva de Meredón in Sierra de Omoa, both of which are parks in the Department of Cortés. Besides occurring in a protected area, there are no specific conservation actions being taken to protect this endangered species (IUCN 2019).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Urbanization
Prolonged drought
Floods
Local pesticides, fertilizers, and pollutants
Disease
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

PHYLOGENETIC RELATIONSHIPS:

Phylogenetic analysis of nuclear and mitochondrial genes of the family Hylidae by Faivovich et al. (2005) resulted in the creation of the genus Bromeliohyla. In 2018, Faivovich et al. re-estimated the Hylidae phylogeny resulting in the addition of B. melacaena (formerly of the genus Isthmohyla) to the genus Bromeliohyla with 87% jackknife support. However, the 2018 analysis did not include all three members of Bromeliohyla.

ETYMOLOGY:

The genus name Bromeliohyla is the combination of the words “Bromelia” and “Hyla”, to represent the characteristic behavior of breeding in bromeliads (Faviovich et al. 2005).

The specific epithet “melacaena” comes from the word “melas”, meaning “black” in Greek, and the word “akaina”, meaning “spine” or “thorn” in Greek. This name was created in reference to the large black spines found on the thumbs of adult male B. melacaena (McCranie and Castañeda 2006).

OTHER INTERESTING INFORMATION:

Bromeliohyla melacaena was originally named Hyla melacaena in a paper by McCranie and Castañeda (2006). It was then reassigned to Isthmohyla by McCranie in 2007, and, most recently, was reassigned to Bromeliohyla by Faivovich et al. in 2018.

References

Canesco-Márquez, L., López, J.L.A., Manzano, R.L., Mayén, G.G., Benitez, D.H. (2018). “Rediscovery of two threatened species of treefrogs (Anura: Hylidae) from Southern Mexico.” Herpetology Notes 11, 23-29. [link]

Duellman, W. E. (2001). The Hylid Frogs of Middle America. Society for the Study of Amphibians and Reptiles, Ithaca, New York.

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. [link]

Faivovich, J., Pereyra, M.O., Luna, M.C., Hertz, A., Blotto, B.L., Vásquez-Almazán, C.R., McCranie, J.R., Sánchez, D.A., Baêta, D., Araujo-Vieira, K., Köhler, G., Kubicki, B., Campbell, J.A., Frost, D.R., Wheeler, W.C., Haddad, C.F.B. (2018). ''On the monophyly and relationships of several genera of Hylini (Anura: Hylidae: Hylinae), with comments on recent taxonomic changes in Hylids.'' South American Journal of Herpetology, 13(1), 1-32. [link]

IUCN SSC Amphibian Specialist Group. (2019). "Isthmohyla melacaena". The IUCN Red List of Threatened Species 2019: e.T136148A54384826. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T136148A54384826.en.

McCranie, J.R., Castañeda, F.E. (2006). ''A new species of hylid frog from northwestern Honduras.'' Herpetologica , 62(3), 318-323. [link]

Taylor, E. H. (1940). “Two new anuran amphibians from Mexico.” Proceedings of the United States National Museum 89: 43–47.

Vitt, L.J., Caldwell, J. P. (2014). Herpetology: An Introductory Biology of Amphibians and Reptiles (4th ed.). Academic Press, Elsevier, San Diego, CA.

Species Account Citation: AmphibiaWeb 2022 Bromeliohyla melacaena: Ranita de Bromelia Pequeña <https://amphibiaweb.org/species/6882> University of California, Berkeley, CA, USA. Accessed Jun 25, 2022.

Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Jun 2022.

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