Cauca Poison Frog
© 2018 Dr. Peter Janzen (1 of 2)
Diagnosis: Andinobates bombetes can be distinguished from all other dendrobatids by the combination of its distinctive color pattern (black or brown body with red or orange dorsolateral stripes that converge somewhat towards the posterior, often end by the midbody and are nonmetallic, plus a pale green, blue-green, or yellow venter mottled with black, and a lack of flash marks); small body size (16-20 mm adult SVL); and having Finger I shorter than Finger II (Myers and Daly 1980).
Description: The average adult snout-to-vent length is 17.76 mm in males and 18.63 mm in females. The head is narrower than the body, with the widest part of the head between the jaw articulations. The snout is sloping, rounded, or obtuse when viewed laterally, and is bluntly rounded to truncated when viewed from above. Snout length is slightly less than eye length. The canthus rostralis is rounded while the loreal region is vertical and nearly flat. Nares are positioned near the tip of the snout and are directed posterolaterally. The tympanum is concealed posterodorsally. Vomerine teeth are absent. No webbing or lateral fringe is present on fingers or toes. All fingers except the first bear expanded discs. The relative lengths of appressed fingers are 3 > 4 > 2 > 1, with the first finger about ¾ the length of the second finger. The third finger disc of adults is 1.4-2.2 times as wide as the finger, and larger in males. There are divided scutes on the fingertips, as in all dendrobatids. Hind limbs are moderately long, with relative lengths of appressed toes being 4 > 3 > 5 > 2 > 1. Inner and outer metatarsal tubercles are present, with the outer one smaller but more protuberant. The skin is granular dorsally and ventrally, with granulation being the coarsest on the lower back and hind limbs. The inner side of the tarsus bears an obliquely aligned, usually weakly developed, tubercle. Also, a weak tarsal ridge may be present; when present, the tarsal ridge extends from the tarsal tubercle towards the inner metatarsal tubercle. Adult males have well-developed vocal slits and a shallow subgular vocal sac that is not particularly evident externally, and a larger third finger disc than that of females. Males are also about 1 mm shorter than females in both average and maximum SVL (Myers and Daly 1980).
Coloration: Dorsal surfaces are black or dark brown with bright red or orange stripes running dorsolaterally from the snout usually to about midbody (occasionally only to level of arm insertion, or extending the entire body length). The posterior of the head often has a blotch of the same color as the stripes, and the middorsum often has a slight suffusion of the same color or rarely a faint, thin, broken vertebral line. The sides of the body are black (even when the top of the body is brown), with a few spots of yellow or greenish yellow. The upper arm is the same color as the body stripes. The upper lip is the same color as the body stripes or sometimes pale green with some suffusion of red. Small reddish or pale green spots are sometimes present on the underside of the thigh. Dorsal surfaces of the hands and feet commonly have a small blotch of bluish green, pale green, or yellow. Digits are light brown or gray, with dark gray palms and soles. Ventral surfaces of the arms are black with small pale spots. Ventral surfaces of the head, body, and hind limbs are mottled black on pale green, pale yellow, or pale bluish green. Tongue and mouth lining are blackish gray. The iris is very dark brown, giving almost no contrast with the pupil (Myers and Daly 1980).
Tadpoles: At stage 25 (external gills absorbed and no indication of hind limb buds), the body width is about ¾ the head-body length. The body is somewhat globular in dorsal view. Both body and head are depressed. Eyes and nostrils are located dorsally and directed dorsolaterally. The spiracle is sinistral and low and the vent is dextral. The tail averages 64% of total length and has a low tail fin that stops short of reaching the body. The tail tip is rounded. The oral disc lacks a definite edge at the anterior and is indented laterally, with a single row of papillae having a median gap. The beak is massive and serrated. Tooth-row formula is 2/3, with A2 having a broad median gap and P1 or P3 sometimes having a narrow median gap. Tadpoles are grayish-brown with the tail having a translucent tip (Myers and Daly 1980).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Population demographics varied depending on habitat type. Populations in marginal habitat in relatively dry forest were found to be small and composed of relatively higher numbers of juveniles and smaller adults, implying a higher turnover. In contrast, populations found in cooler and moister montane forest had higher numbers of individuals with a greater proportion of large (older?) adults (Myers and Daly 1980).
Trends and Threats
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
Etymology: The specific epithet bombetes derives from the Greek word “bombus,” meaning to buzz (like bees), in reference to the insect-like call of the species (Myers and Daly 1980).
Daly, J. W. (1998). ''Thirty years of discovering arthropod alkaloids in amphibian skin.'' Journal of Natural Products , 61, 162-172.
Myers, C.W. and Daly, J.W. (1980). ''Taxonomy and ecology of Dendrobates bombetes, a new Andean poison frog with new skin toxins.'' American Museum Novitates, 2692, 1-23.
Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.
Weldon, P. J., Kramer M., Gordon, S., Spande, T. F., and Daly, J. W. (2006). ''A common pumiliotoxin from poison frogs exhibits enantioselective toxicity against mosquitoes.'' Proceedings of the National Academy of Sciences USA, 103, 17818-17821.
Written by: Richard Gilbert (rgilbert AT csustan.edu), California State University Stanislaus
First submitted 2010-09-23
Edited by Kellie Whittaker (2012-02-15)
Species Account Citation: AmphibiaWeb 2012 Andinobates bombetes: Cauca Poison Frog <http://amphibiaweb.org/species/1689> University of California, Berkeley, CA, USA. Accessed Mar 8, 2021.
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Citation: AmphibiaWeb. 2021. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 8 Mar 2021.
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