AMPHIBIAWEB
Eleutherodactylus johnstonei
Johnstone's Whistling Frog
Subgenus: Eleutherodactylus
family: Eleutherodactylidae
subfamily: Eleutherodactylinae

© 2015 Sandra Goutte (1 of 11)

View distribution map using BerkeleyMapper.


Conservation Status (definitions)
IUCN (Red List) Status Least Concern (LC)
See IUCN account.
CITES No CITES Listing
Other International Status None
National Status None
Regional Status None

   

Description
A small, dull-colored frog, adult males are 17-25 mm long and adult females, 17-35 mm. Brown to gray tan dorsal ground color with usually one or two darker chevrons. Often a narrow middorsal pinstripe or a broad pair of dorsal stripes. Marbled, stippled, or blotched on a dark brown to gray tan ground posterior thigh surface and creamy undersurface. Iris gold above and brownish below (Savage 2002).
Smooth to slightly tuberculate dorsum; head a little broader than long; snout truncate from above; large eyes with eyelids that have many low, rounded tubercles. Distinct tympanum; oblique vomerine odontophores. Distinct, small, rounded finger and toe disks; lacks digital webbing. Many small plantar tubercles; elongate inner metatarsal tubercle larger than conical outer metatarsal tubercle; lacks tarsal fold. Adult males have paired vocal slits and a distensible internal subgular vocal sac strongly granular when uninflated; lacks nuptial thumb pads (Savage 2002).

Similar Species: E. ridens has enlarged, pointed supraocular tubercles on upper eyelids, red thighs, calves, and feet. E. cruentus has large truncate and emarginate disks on fingers (Savage 2002).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Anguilla, Antigua and Barbuda, Barbados, Dominica, Grenada, Guadeloupe, Martinique, Montserrat, Netherlands Antilles, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines. Introduced: Aruba, Bermuda, Brazil, Colombia, Costa Rica, French Guiana, Guyana, Jamaica, Panama, Trinidad and Tobago, Venezuela.

View distribution map using BerkeleyMapper.
Often found in primary succession vegetation, disturbed areas caused by natural or human means such as the aftermath of lava flow, cut down forests, and residential areas. Usually not found in undisturbed areas of abundant local endemics (Kaiser 1997).

Anguilla, Antigua and Barbuda, Barbados, Bermuda, Costa Rica, Dominica, Grenada, Guyana, Guadeloupe, the Grenadines, Jamaica, Martinique, Montserrat, Netherlands Antilles, Panama, Saint Kitts and Nevis, Saint Lucia, Saint Vincent, Trinidad, Tobago, Venezuela

Life History, Abundance, Activity, and Special Behaviors
Diet: Eats mostly ants, but also spiders, leafhoppers, and springtails (Savage 2002).

Mating Behavior: During wet season, peaks around June to August (Ovaska 1991; Savage 2002). Females approach calling males to initiate courtship. Repeatedly, a male moves away, calling softly, and the female follows until both reach a possible oviposition site. Other males may follow and compete for the female with calls and, sometimes, physical means. Female accepts male by backing under him. Male clasps female in axillary amplexus or perches on her back; less often, a pair uses a reverse hind leg clasp, a position only known in E. coqui, which has internal fertilization. Both go through abdominal pulsations and body spasms before the female begins to lay eggs (Bourne 1997).

Eggs and Froglets: Clutches found throughout the year but most often during the wettest months and contain 10-30 unpigmented eggs covered in a thin layer of viscous mucus. Newly laid, egg diameters average around 3.0 mm. Froglets hatch from the eggs by using an egg tooth located on the tip of the snout. They have snout vent lengths of about 4.0 mm. Their short stumpy tails disappear within a day, and the froglets reach sexual maturity in about one year (Bourne 1997; Savage 2002).

Call: Two-note whistle that can be repeated at a maximum of 60 times per minute. First note, frequency about 2 kHz for 70-90 milliseconds. Longer second note, lasting 180-270 milliseconds, that rises sharply from about 3 to 4 kHz. Average interval between calls is 1.2 seconds (Savage 2002).
Oviposition calls are identical to diurnal retreat calls, but are different from lead away calls of initial courtship by duration and frequency (Bourne 1997).

Trends and Threats
E. johnstonei is often introduced as a stowaway via trade amongst the islands and outcompetes local frog species in tougher environments, therefore increasing its own population distribution. Intensive monitoring is needed of each island with E. johnstonei and native species to see if the former is responsible for the decline of the latter. If there is confirmation that E. johnstonei is responsible, suggested methods in controlling population levels are to initiate management programs to educate officials, tighten control over agricultural imports, monitor range at intervals and boundaries by geographic information system, and preserve native habitats (Kaiser 1997).

Comments
Thomas Barbour in 1914 named the species after Robert S. Johnstone, Chief Justice of Grenada. Often confused with E. martinicensis (Kaiser 1997).

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

References

Bourne, G. R. (1997). ''Reproductive behavior of terrestrial breeding frogs Eleutherodactylus johnstonei in Guyana.'' Journal of Herpetology, 31(2), 221-229.

Kaiser, H. (1997). ''Origins and introductions of the Caribbean frog, Eleutherodactylus johnstonei (Leptodactylidae): management and conservation concerns.'' Biodiversity and Conservation, 6, 1391-1407.

Ovaska, K. (1991). ''Reproductive phenology, population structure, and habitat use of the frog Eleutherodactylus johnstonei in Barbados, West Indies.'' Journal of Herpetology, 25(4), 424-430.

Savage, J. M. (2002). The Amphibians and Reptiles of Costa Rica. University of Chicago Press, Chicago and London.



Written by Chih Wang (chihwang AT uclink.berkeley.edu), AmphibiaWeb
First submitted 2003-03-19
Edited by Tate Tunstall (2009-11-02)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2016. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Sep 26, 2016).

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