Diagnosis: Small dark blue-green dorsum, generally with scattered black spots. Snout is obtuse in profile. Dark green bones. White stripe on upper lip. Parietal peritoneal sheath, pericardium, and digestive tract white (Savage 2002).
Description: Adult males 22.5-29 mm SVL, adult females 29-32 mm SVL. Head wider than long. Snout is rounded in dorsal view, obtuse in profile. Nares are not protuberant and are directed dorsolaterally. Eyes are large but not protuberant. Interorbital width considerably exceeds the eye diameter. Tympanum is round and indistinct. Vomerine odontophores are round with only a few teeth present, and are located between choanae. Finger I is slightly longer than Finger II. Both finger and toe discs are truncated. Fingers I and II have no webbing in between, but there is vestigial webbing between Fingers II and III, and more developed webbing between Fingers II and IV. Toes are moderately webbed. There is no tarsal fold or tubercle present. No fringing is present on arms or legs. Dorsal skin surfaces are very granular. Males have a large, well-developed white nuptial pad on the dorsal and outer lateral margin of the base of each thumb (Savage 2002).
Coloration is dark blue-green, with scattered black spots usually present. Parietal peritoneal sheath covering anterior internal organs, white pericardium, and white digestive tract are present. Liver is reddish. Bones are dark green. Upper lip has a white stripe. Iris is pale gray-gold (Savage 2002).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Costa Rica, Honduras, Nicaragua, Panama
Eastern Honduras to central Panama, and northern Costa Rica to southwestern Panama (Köhler 2001; Savage 2002; McCranie and Wilson 2002; McCranie 2007; Kubicki 2007), in the moist lowlands and premontane slopes at 40-1,500 m asl (Savage 2002).
Although Cochranella granulosa is found in Costa Rica, Honduras, Nicaragua, and Panama, there are few records from Honduras and Nicaragua (Solís et al. 2008).
Life History, Abundance, Activity, and Special Behaviors
Cochranella granulosa is a nocturnal species (Savage 2002). Males call from trees 5-10 m above fast-flowing streams (Savage 2002). The call is a series of rapid harsh notes "creep-creep-creep" at a dominant frequency of 4-4.5 kHz (Savage 2002). Eggs are generally laid arboreally above streams in a single-layered jelly mass approximately 20 X 35 mm, with each clutch containing 49-60 eggs (Savage 2002), although this species also occasionally breeds in ponds (Guayasamin et al. 2009). Eggs are black and white and measure 1.5 mm in diameter by themselves or 3 mm with the envelope (Savage 2002). The jelly mass hangs over the edge of the leaf, forming a drip tip so that water constantly flows over the eggs (Savage 2002). No long-term parental care is provided (Savage 2002). The tadpole is a detritivore that burrows in deposits of organic materials (Altig et al. 2007).
Larvae are 11 mm at stage 25 with an elongated and slightly depressed body. Nostrils and eyes are dorsal. Spiracle is located sinistrally and is much closer to the posterior margin of the body than the eye. Vent tube is located in the middle. Mouth is ventral. A complete oral disc, beaks, and 2/3 rows of denticles are present. Lower beak has large blunt serrations. A2 is restricted to two short segments on either side of the mouth. P3 is equal to or only slightly shorter than other posterior tooth rows. A single row of labial papillae is present around the sides and bottom of the oral disc but not above mouth. The tail is long with reduced caudal fins and a round tip (Savage 2002; Lips and Savage 1996).
Upon hatching, larval coloration is black. As the tadpole matures, it becomes pale brown with translucent fins; the fins have sparse dark spotting toward the posterior (Savage 2002).
Trends and Threats
This species is found in a number of protected areas, but in the rest of its range it is threatened by severe deforestation (Solís et al. 2008). It requires primary forest (Furlani et al. 2009). Water pollution also presents a threat (Solís et al. 2008).
Possible reasons for amphibian decline
General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Local pesticides, fertilizers, and pollutants
The specific epithet granulosa is derived from the Latin word granulum, meaning small-grained or granular, referring to the granular skin of this species (McCranie and Wilson 2002).
The karyotype is 2N = 20 (Duellman 1967).
Altig, R., Whiles, M. R., and Taylor, C. L. (2007). ''What do tadpoles really eat? Assessing the trophic status of an understudied and imperiled group of consumers in freshwater habitats.'' Freshwater Biology, 52, 386-395.
Duellman, W. E. (1967). ''Additional studies of chromosomes of anuran amphibians.'' Systematic Zoology, 16(1), 38-43.
Furlani, D., Ficetola, G. F., Colombo, G., Ugurlucan, M., and De Bernardi, F. (2009). ''Deforestation and the structure of frog communities in the Humedale Terraba-Sierpe, Costa Rica.'' Zoological Science, 26, 197-202.
Guayasamin, J. M., Castroviejo-Fisher, S., Trueb, L., Ayarzaguena, J., Rada, M., Vila, C. (2009). ''Phylogenetic systematics of glassfrogs (Amphibia: Centrolenidae) and their sister taxon Allophryne ruthveni.'' Zootaxa, 2100, 1-97.
Ibañez, R., Rand, A. S. and Jaramillo, C. A. (1999). Los Anfibios del Monumento Natural Barro Colorado, Parque Nacional Soberanía y Areas Adyacentes. Mizrachi, E. and Pujol, S. A., Santa Fe de Bogota.
Ibañez, R., Solís, F., Jaramillo, C. and Rand, S. (2000). ''An overview of the herpetology of Panama.'' Mesoamerican Herpetology: Systematics, Zoogeography and Conservation. Johnson, J. D., Webb, R. G. and Flores-Villela, O. A., eds., The University of Texas at El Paso, El Paso, Texas, 159-170.
Kubicki, B. (2007). Glass Frogs of Costa Rica/ Rana de Vidrio de Costa Rica. Editorial INBio, Costa Rica.
Köhler, G. (2001). Anfibios y Reptiles de Nicaragua. Herpeton, Offenbach, Federal Republic of Germany.
Lips, K. L., and Savage, J. M. (1996). ''Key to the known tadpoles (Amphibia: Anura) of Costa Rica.'' Studies on Neotropical Fauna and Environment, 31, 17-26.
McCranie, J. R. (2007). ''Distribution of the amphibians of Honduras by departments.'' Herpetological Review, 38(1), 35-39.
McCranie, J. R., and Wilson, L. D. (2002). ''The Amphibians of Honduras.'' Contributions to Herpetology, Vol 19. K. Adler and T. D. Perry, eds., Society for the Study of Amphibians and Reptiles, Ithaca, New York.
Savage, J. M. (2002). The Amphibians and Reptiles of Costa Rica:a herpetofauna between two continents, between two seas. University of Chicago Press, Chicago, Illinois, USA and London.
Solís, F., Ibáñez, R., Jaramillo, C., Chaves, G., Savage, J., Cruz, G., Wilson, L.D., Köhler, G. and Kubicki, B. (2004). Cochranella granulosa. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. www.iucnredlist.org. Downloaded on 05 October 2009.
Originally submitted by: Sandya Iyer (first posted 2009-09-14)
Edited by: Kellie Whittaker, Michelle S. Koo (2022-08-15)
Species Account Citation: AmphibiaWeb 2022 Cochranella granulosa: Granular Glassfrog <https://amphibiaweb.org/species/1770> University of California, Berkeley, CA, USA. Accessed Dec 2, 2022.
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Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 2 Dec 2022.
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