Description
Craugastor underwoodi is a small frog, with males ranging in size from 16 - 26 mm snout-vent length, and females ranging from 18.4 – 30 mm snout-vent length. The head is narrow with no cranial crests. When viewed from above, the snout is rounded. Eyes are relatively large and the distinct, transparent tympanum is about the same size as the eye in male and about ¾ the size of the eye in females. Neither sex has vocal sacs or slits. Fingers 1 and 2 are approximately the same length and fingers 3 and 4 have groves and narrow discs at the ends. In males there are nuptial pads at the base of the thumbs. There are low, globular, oval tubercles on the palms. Expanded discs are present on the toes and are often pointed and asymmetrical. Hands and feet have projecting oval subarticular tubercles that are low and globular. No toe webbing. Warts can be found on the heels, and a few round tubercles can be found on the bottom of the foot, widely spaced. The dorsal surface is often warty with some X-or W-shaped ridging. The venter is coarsely marked (Pounds and Fogden 2000; Savage 2002).

This species can be distinguished from other morphologically similar leaf litter frogs by the complete absence of webbing between fingers and toes. It is most often confused with other frogs in the Craugastor rhodopis group, especially C. podiciferus, whose range and activity overlaps with that of C. underwoodi. However, the dark eye mask that characterizes C. podiciferus is typically absent in C. underwoodi. Additionally, the tubercles on the hands and feet of C. underwoodi are comparatively smoother, less prominent and more globular. Craugastor underwoodi is also similar to C. bransfordii, which is smaller and has more pointed tubercles on the palms and planters, and C. polyptchus, which also has pointed tubercles and whose males lack nuptial pads (Pounds and Fogden 2000; Savage 2002).

Individuals of this species generally have a light brown dorsal surface with barring on the legs and a variety of other markings that may include a dark bar between the eyes, a dark or light patch between the shoulders, and dorsolateral or mid-dorsal stripes. The ventral surface is usually yellow with some mottling, and the inner thighs and groin often display a reddish coloration. The pupils tend to be coppery-brown (Pounds and Fogden 2000; Savage 2002).

The polymorphism and polychromatism in many frogs of the genus Craugastor often make it exceedingly difficult to differentiate between species. Individuals of C. underwoodi vary widely in skin texture and markings, with some frogs bearing extensive stripes or markings and others displaying more uniform coloration. The skin may be extremely warty or smoother with a varying degree of ridging (Pounds and Fogden 2000; Savage 2002).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Costa Rica, Panama

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (1 records).

Craugastor underwoodi inhabits the tropical premontane and lower montane wet forests and rain forests of Costa Rica along both the Atlantic and Pacific versants of the Cordillera Central, Cordillera Costeña, Cordillera de Tilarán, and Cordillera de Talamanca up to western Panama. This species has been also documented in plantations, pastures and secondary forests. It can be found at elevations from 920-1800 meters above sea level (Pounds and Fogden 2000; Savage 2002).

Life History, Abundance, Activity, and Special Behaviors
Craugastor underwoodi is a fairly abundant diurnal leaf litter frog that exhibits axillary amplexus and undergoes direct development. Its diet consists of arthropods, and its call is a “squeak-squeak” (Savage 2002).

Trends and Threats
Craugastor underwoodi is thought to be stable with no known threats, although extreme polymorphism and polychromatism make this species challenging to identify. Consequently, there is a deficit of data on C. underwoodi populations (Pounds et al. 2004).

Comments
The karyotype of this frog is 2N = 18 (Savage 2002).

The species authority is Boulenger (1896)

Craugastor underwoodi was previously placed in the family Eleutherodactylidae, genus Eleutherodactylus. Other names for this species include Eleutherodactylus underwoodi, Hylodes underwoodi, and Microbatracheus underwoodi (Crawford and Smith 2005). Craugastor underwoodi was also briefly lumped with Craugastor bransfordii (Savage 2002).

Craugastor underwoodi was named for the herpetologist Garth Underwood (Pounds and Fogden 2000).

A Spanish-language species account can be found at the website of Instituto Nacional de Biodiversidad (INBio).

References

Crawford, A. J., and Smith, E. N. (2005). ''Cenozoic biogeography and evolution in direct-developing frogs of Central America (Leptodactylidae: Eleutherodactylus) as inferred from a phylogenetic analysis of nuclear and mitochondrial genes.'' Molecular Phylogenetics and Evolution, 35, 536-555.

Pounds, A., Bolaños, F., Solís, F., Ibáñez, R., Chaves, G., Savage, J., Jaramillo, C., and Fuenmayor, Q. (2004). Craugastor underwoodi. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org. Downloaded on 02 May 2013.

Pounds, J. A., Fogden, M.P. (2002). ''Appendix 8: Amphibians and Reptiles of Monteverde.'' Monteverde: Ecology and Conservation of a Tropical Cloud Forest. Nadkarni, N.M. and Wheelwright, N.T, eds., Oxford University Press, Oxford, UK.

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.

Species Account Citation: AmphibiaWeb 2013 Craugastor underwoodi: Underwood’s Litter Frog <https://amphibiaweb.org/species/6607> University of California, Berkeley, CA, USA. Accessed Nov 27, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 27 Nov 2024.

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