Chiriqui Harlequin Frog
© 2010 Division of Herpetology, University of Kansas (1 of 2)
Atelopus chiriquiensis, the Chiriqui Harlequin Frog, is a moderately-sized frog with males reaching 28-34 mm and females 36-49 mm (Savage 2002). The head is angular and longer than it is wide, and lacks a visible tympanum (Savage 2002). The canthus rostralis is well-defined in this species (Savage 2002). The undersides of the hands and feet are wrinkled and fleshy (Savage 2002). Paired metarsal and subarticular tubercles are present. Toes have extensive webbing. Adult males have paired vocal slits and a single subgular vocal sac, located internally, as well as brown nuptial pads on the thumbs (Savage 2002). Occasionally adults of either sex will have prominent small spicules along the anterior flank (Savage 2002).
This species is highly variable in color. Males have a uniformly yellow, chartreuse, lime green or brownish red coloration (Leenders 2001; Savage 2002). On occasion males will also have a pattern consisting of thin black reticulations, or fine dark vermiculations (Savage 2002). Females are more variable in color, and are rarely similar to the males in coloration (Savage 2002). Many females have an orange or orange-red stripe, outlined in black, which begins at the snout and then splits into two stripes running down the sides of the back to the groin (Savage 2002; Leenders 2001). The stripes may also break up into long splotches (Savage 2002). In both sexes the ventrum is usually yellow, and generally without pattern; females sometimes have a broad black and red reticulum ventrally (Savage 2002). Both females and males have orangish or greenish eye color, and sometimes they may even have an eye of each color (Leenders 2001). The iris is gold (Savage 2002).This species has weakly developed and relatively inconspicuous poison glands, which are scattered over the head and dorsum (Leenders 2001), distinguishing it from related species. In contrast, Atelopus varius has no differentiated glandular areas, and Atelopus senex has very prominent glands (Savage 2002).
A. chiriquiensis tadpoles are gastromyzophorous, with 2/3 denticle rows, and resemble those of Atelopus varius (Savage 2002).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Costa Rica, Panama
Life History, Abundance, Activity, and Special Behaviors
Breeding takes during the dry season in Panama (February) (Lindquist and Swihart 1997), or in the early wet season in Costa Rica (May to July) (Savage 2002). Advertisement calls have been described as a buzz or a pulsed call (Savage 2002). Chiriqui Harlequin Frogs in Parque Internacional La Amistad, Provincia de Chiriqui, Panama, were observed mating (Lindquist and Swihart 1997). The habitat consisted of swift montane streams with water temperatures of 10.8 degrees C and air temperatures of 17.6 degress C, in cloud forests of 2005-2100 meters. Mating behavior occurred during both daytime and nighttime. The observed mating sex ratio was 1 female to 7 males. Females are on average 1.5x the size of males. Amplexus is axillary (Lindquist and Swihart 1997), and is initiated well before egg laying (Savage 2002). Frogs of the genus Atelopus are known for remaining in amplexus for extended periods of time, even up to several weeks (Leenders 2001). Males not in amplexus with a female were observed trying to dislodge other males from females, but these attempts were not successful. Amplectant mating pairs submerge themselves completely in the stream for 15-30 minutes, either to avoid attempts by other males to disrupt the mating, or possibly for females to look for egg laying sites (Lindquist and Swihart 1997).
Female egg laying behavior was observed in the laboratory. Female A. chiriquiensis chose to deposit eggs in small containers containing partial amounts of unchlorinated water. Eggs were laid in a continuous process over an 8-10 hour period, producing in total two strings of ~364 unpigmented eggs. The eggs were all laid in a massive clutch, making it difficult to separate eggs without breaking the strings. The strings measured 36-44 cm in length, with an egg density of 11-13 eggs per 25 mm segment. Egg diameter was measured at 2.05 mm, and in its protective gel case the diameter was 3.63 mm. During egg laying the male performed a leg-kicking action, in which he kicked his leg 2-3 times before the female would lay 3-5 eggs onto the string. A possible reason for the leg-kicking behavior was to provide a tactile cue to the female to help her synchronize her egg release with milting. The eggs in the laboratory did not develop (Lindquist and Swihart 1997).
When researchers returned to the original breeding site in August they found that most Chiriqui Harlequin Frogs had left the area. Only a very small number of amplectant pairs and single individuals were left, suggesting migration within the species. Migration appeared to be tied to the local rainfall patterns (Lindquist and Swihart 1997).
These toads produce tetrodotoxin, a potent neurotoxin (Leenders 2001).
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
A Spanish-language species account can be found at the website of Instituto Nacional de Biodiversidad (INBio).
Leenders, T. (2001). A Guide to Amphibians And Reptiles of Costa Rica. Zona Tropical, Miami.
Lindquist, E. D., and Swihart, D. W. (1997). ''Atelopus chiriquiensis (Chiriqui Harlequin Frog). Mating behaviour and egg-laying.'' Herpetological Review, 3(28), 145-146.
Lips, K. R. (1998). ''Decline of a tropical montane amphibian fauna.'' Conservation Biology, 12(1), 106-117.
Savage, J. M. (2002). The Amphibians and Reptiles of Costa Rica. University of Chicago Press, Chicago and London.
Written by Natalie Levy (njl AT berkeley.edu), UC Berkeley
First submitted 2007-02-20
Edited by Kellie Whittaker (2010-09-08)
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