AmphibiaWeb - Craugastor crassidigitus


(Translations may not be accurate.)

Craugastor crassidigitus (Taylor, 1952)
Isla Bonita Robber Frog
Subgenus: Craugastor
family: Craugastoridae
genus: Craugastor
Craugastor crassidigitus
© 2010 Sean Michael Rovito (1 of 17)
Conservation Status (definitions)
IUCN Red List Status Account Least Concern (LC)
National Status None
Regional Status None
conservation needs Access Conservation Needs Assessment Report .


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Diagnosis: The SVL of Craugastor crassidigitus varies between approximately 20.2 mm and 44.7 mm among its four populations in Panama. There is extensive webbing between toes II, III and IV, which is used to distinguish C. crassidigitus from similar frogs (Lynch and Myers 1983).

Description: The head is relatively narrow, measuring at 35.5-41.0% of the SVL. The snout is subacuminate and moderate in length. The tympanum is distinct and measures at one-half to two-thirds the length of the eye in males and two-fifths to three-fifths the eye length in females. The dorsal skin is shagreened with warts on the scapular region. Fingers I and II have round discs and fingers III and IV are truncated. Toes are moderately webbed with lateral fringes on the unwebbed portions. Males have a subgular vocal sac and vocal slits, but are usually not visible externally. Males also have nuptial pads on their thumbs, which are non-spinous (Lynch and Myers 1983)


Coloration and Coloration Variation: Dorsal coloring varies widely in C. crassidigitus. Costa Rican populations are lavender to reddish olive brown. Panamanian populations can be grey, grayish brown, light or dark brown, pinkish brown, orangish brown, and reddish brown. The venter is typically white or light yellow. The limbs are pale green or yellow underneath, and sometimes even orange. Individuals may have thighs, which are suffused, or flecked, with orange and red. Throat coloration is highly variable, ranging from white to black. The lower part of the iris is pale grey, while the upper iris can be grey, bronze, brown or red. C. crassidigitus has three main patterns: (1) uniform background color with dark markings on the back, typically an hourglass, scapular butterfly, or a W, and a bar or butterfly between the eyes (2) pale, unmarked coloration from snout to end of body, with dark lines along the edge of the dorsum, and (3) similar to type 2, but with a pale median stripe (Lynch and Myers 1983).

Distribution and Habitat

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

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C. crassidigitus is found in western and central Panama, as well as throughout Costa Rica, and along the Colombian border. It is a terrestrial species, which occurs in lowland rain forests including mature and second-growth forests, as well as in brushy pasture, coffee plantations, and on rocks along stream banks. It is most abundant at elevations below 1500 m (Lynch and Myers 1983).

Life History, Abundance, Activity, and Special Behaviors
C. crassidigitus is most often found on the forest floor at night, but has also been spotted in leaf litter during the day, suggesting some degree of being diurnal. C. crassidigitus is also found among rocks along stream beds, but has no aquatic behavior. It also avoids water-containing bromeliads, even during the dry season.

Males do call, usually from twigs or other perches near the ground. Calls are rare during the dry season, even though the frogs are active. There are two known calls: a birdlike chirp and a chuck chirp. The birdlike chirp is approximately 0.10-0.12 s long, measured at 1400-4500 Hz. These calls are evenly pulsed, but there is some variation among males. The chuck chirp is 0.02-0.13 s long, and the short notes sound like clicks. Chuck chirps are non-melodious, start out slow and speed up at the end. It is unknown if these calls change when encountering intruders or potential mates. Females are also thought to give calls when in distress (Lynch and Myers 1983).

C. crassidigitus has direct development (Solis et al. 2008).

Trends and Threats
The population is stable and is not currently facing any threats. However, it is still found in one protected area, National Natural Katios Park in Colombia (Solis et al. 2008).

Relation to Humans
This species is found in coffee plantations (Lynch and Myers 1983).

C. crassidigitus was previously named Eleutherodactylus crassidigitus, but is now part of the family Craugastoridae (Crawford and Smith 2005).


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.

Lynch, J. D., and Myers, C. W. (1983). ''Frogs of the fitzingeri group of Eleutherodactylus in eastern Panama and Chocoan South America (Leptodactylidae).'' Bulletin of the American Museum of Natural History, 175(5), 484-568.

Solís, F., Ibáñez, R., Chaves, G., Savage, J., Jaramillo, C., Fuenmayor, Q., Lynch, J., and Bolaños, F. (2008). Craugastor crassidigitus. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. Downloaded on 29 April 2011.

Originally submitted by: Angela Flemming (first posted 2009-11-02)
Edited by: Kandys Kim, Michelle S. Koo (2023-03-15)

Species Account Citation: AmphibiaWeb 2023 Craugastor crassidigitus: Isla Bonita Robber Frog <> University of California, Berkeley, CA, USA. Accessed Jul 16, 2024.

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Citation: AmphibiaWeb. 2024. <> University of California, Berkeley, CA, USA. Accessed 16 Jul 2024.

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