© 2004 Luis J. Villanueva-Rivera (1 of 1)
Eleutherodactylus portoricensis can be differentiated from E. auriculatus by call and behavior. The former’s call sounds like a repeated “coqui” and the latter’s more closely resembles “chi-leén”. The former also breeds in bromeliads while the latter does not (Schmidt 1927).
In life the concealed parts of the thighs are reddish and immaculate. In preservative, the color of the frog is dark grey-brown. There is a light band starting from the canthus, over the eye to the tympanum, where it broadens and merges into the light colored belly (Schmidt 1927).
The gular region area of the females have no folded skin but the gular region of the male have folded skin, indicating a vocal sac (Ríos-López et al. 2015). There is also a high variability in coloration (Schmidt 1927).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Puerto Rico
Life History, Abundance, Activity, and Special Behaviors
The male E. portoricensis produce advertisement calls in their home range at night (Drewry and Rand 1983) from bushes and tree trunks (Angulo 2008). They have one to two types of notes per call with both lengths 50 - 80 msec. The note interval is 92 - 200 msec, and the dominant frequency of the two types of note is 1.5 - 1.8 and 2.2 - 3.0 kHz. The calls have a ramping pattern that the rate of calling increases to a peak and then calling stops suddenly (Drewry and Rand 1983).
Axillary amplexus was observed in a captive pair and in March 2016 a wild mating pair were found in a research tube set for the purpose of surveying frogs. During ovipositioning, the female of the species was observed using a reverse hind-leg grasp, positioning her legs above the males and holding on to his waist. This behavior was similar to the positioning observed in captivity and may help with internal fertilization, which is presumed in E. portoricensis. Hind-leg grasping and internal fertilization have also been documented in E. coqui, which is closely related and whose behavior E. portoricensis is presumed to be similar to (Ríos-López et al. 2016).
When disturbed during ovipositioning, both in the field and in captivity, males are known to consume newly laid eggs (Ríos-López et al. 2015 and 2016). Additionally, because females barely feed when gravid, if females are not removed from terrariums in captivity after laying eggs, they will consume the eggs or disturb males enough that the males will consume the eggs (Ríos-López et al. 2015).
Eleutherodactylus portoricensis lay clusters of eggs in bromeliads (Angulo 2008) a few inches above rainwater on the upper side of the lowest leaf petiole (Gitlin 1944). Multiple clusters have been found together in both the wild and in captivity (Gitlin 1944, Rio-Lopez et al. 2015). The species has direct development, with froglets emerging from eggs, and has male parental care (guarding) (Río-López et al. 2015). There are approximately 13 to 24 eggs per clutch; the diameter of the eggs is 5.1 mm on average (Joglar 1998). The development period for E. portoricensis varies from 22.3 days to 33.5 days (Río-López et al. 2015). Eggs can be found year round indicating an indefinite breeding season (Gitlin 1944).
Eleutherodactylus portoricensis has direct development and the limbs are formed within the egg. At temperatures ranging from 21 – 25.5oC, the hind-limbs emerged 6 hours before the forelimbs (Gitlin 1944).
In captivity, juveniles will reach adult size at 20 – 22 months but may not be sexually mature at that point. Wild individuals may take longer to reach adult size and maturity because of lack of resources(Ríos-López et al. 2015).
Eleutherodactylus portoricensis preys on invertebrates (mainly arthropods) such as ants, cockroaches, and cricket etc. with “sit-and-wait” strategy (Stewart and Woodbright 1996). The predators of juvenile E. portoricensis are invertebrates such as Sparassidae spiders, while reptiles and other anurans prey on adult E. portoricensis (Stewart and Woodbright 1996).
Trends and Threats
Eleutherodactylus portoricensis is rare and listed as “Endangered” by the IUCN Red List since 2004 (Angulo 2008). The population of E. portoricensis in El Yunque (Caribbean National Forest) has increased, but the population in Colorado Forest, which is about 200 m below the Elfin Forest of the El Yunque , has decreased (Burrowes et al. 2004). The main factors that associated with the decline of E. portoricensis are linked to chytrid fungal infections caused by Batrachochytrium dendrobatidis and the reduction of precipitation. This is a problem because the anurans lose water easily through their skin (Burrowes et al. 2004). The secondary causes for the declination of E. portoricensis includes pathogens and parasites such as acanthocephalan worms in stomachs and intestines, protozoan, and helminthic parasites (Burrowes et al. 2004). There is some habitat loss but not enough to explain the greater than 50% decline observed in this species (Angulo 2008).
Due to their dire situation, E. portoricensis are involved in an ex situ captive breeding project (Río-López et al. 2015).
Possible reasons for amphibian decline
Eleutherodactylus portoricensis is closely related to E. antillensis and E. coqui (Ríos-López et al. 2015).
In 1871 Bello Espinosa described a Puerto Rican tree toad that natives called, "Coqui", and in 1876 Peters reported that Gundlach had found some eggs of E. coqui because Gundlach observations pointed it to being a coqui. However Sampson’s research on the embryology of the Jamaican E. luteolus and E. nubicola showed that the species they found were not E. coqui, but rather E. portoricensis. The name was proposed by Schmidt (1927) after investigating into the confusion between Puerto Rican species with E. martinicensis (Gitlin 1944).
The name "Eleutherodactylus" is derived from the Greek words for ‘free-toed’, by combining eleutheros (‘free, unbound’) and dactylos (‘finger, toe’) (Kenneth 2013).
Even though the species E. portoricensis is Endangered, its sister species, E. coqui are an invasive species in Hawaii, and are seen as pests (Kalnicky et al. 2014).
Angulo, A., 2008. Eleutherodactylus portoricensis. The IUCN Red List of Threatened Species 2008: e.T56875A11547757. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T56875A11547757.en. Downloaded on 19 February 2017.
Burrowes, P. A., Joglar, R. L., and Green, D. E. (2004). ''Potential causes for amphibian declines in Puerto Rico.'' Herpetologica, 60, 141-154.
Drewry, G. E., Rand, A. S. (1983). ''Characteristics of an Acoustic Community: Puerto Rican Frogs of the Genus Eleutherodactylus.'' Copeia, 1983(4), 941-953.
Gitlin, D. (1944). ''The Development of Eleutherodactylus portoricensis.'' American Society of Ichthyologists and Herpetologists, 1944(2), 91-98.
Joglar, R. L. (1998). Los Coquíes de Puerto Rico: Su Historia Natural y Conservación. University of Puerto Rico Press, Puerto Rico.
Kalnicky, E. A., Brunson, M. W., Beard, K. H. (2014). ''A social–ecological systems approach to non-native species: Habituation and its effect on management of coqui frogs in Hawaii.'' Biological Conservation, 180, 187-195.
Ríos-López N., Agosto-Torres, E., Hernández-Muñíz, R. M., Cao, G. M. (2016). ''Natural History Notes on the Reproductive Biology of the Melodious Coqui, Eleutherodactylus wightmanae (Schmidt, 1920), the Whistling Coqui, E. cochranae (Grant, 1932), and the Mountain Coqui, E. portoricensis (Schmidt, 1927) (Anura: Eleutherodactylidae), from Puerto Rico.'' Life: The Excitement of Biology, 4(1), 3-10.
Ríos-López, N., Agosto-Torres, E., Hernández-Muñíz, R. M., Vicéns-López, C., Bernardi-Salinas, A., Tirado-Casillas, W. N., Flores-Rodríguez, Y. (2015). ''Conservation Efforts for the Puerto Rican Mountain Coqui (Anura: Eleutherodactylidae: Eleutherodactylidae portoricensis Schmidt, 1927): Reproductive Biology in Captivity.'' Life: The Excitement of Biology , 3(2), 61-82.
Schmidt, K.P. (1927). ''A New Tree-Frog from Porto Rico.'' American Museum Novitates, 279, 1-3.
Stewart, M. and Woolbright, L. (1996). ''The Food Web of a Tropical Rain Forest.'' Amphibians. D.P. Reagan and R.B. Waide, eds., University of Chicago Press, United States, 273-320.
Townsend, D., Stewart, M. (1994). ''Reproductive Ecology of the Puerto Rican Frog Eleutherodactylus coqui.'' Journal of Herpetology, 28(1), 34-40.
Written by Allen Huynh, Keth Pichta Pal, Ruoshi Huang (allhuynh AT ucdavis.edu, Kppal AT ucdavis.edu, ruohuang AT ucdavis.edu), University of California Davis
First submitted 2017-08-27
Edited by Ann T. Chang (2017-09-01)
Species Account Citation: AmphibiaWeb 2017 Eleutherodactylus portoricensis: Forest Coqui <http://amphibiaweb.org/species/3144> University of California, Berkeley, CA, USA. Accessed Nov 19, 2018.
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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Nov 2018.
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