Description

Diagnosis: Rana taylori can be distinguished from other Costa Rican frogs by the following combination of characters: large body size (61-88 mm SVL), relatively short legs, distinct but discontinuous dorsolateral folds with the posterior part of the folds offset medially; large dorsal spots that are outlined in a lighter color and are often elongated in shape; webbed feet (Savage 2002).

Description: Rana taylori adult males range from 61-78 mm in standard length and females range from 71 to 88 mm in standard length. R. taylori is a large, fairly short-legged brownish to gray-green frog. It has distinct but discontinuous dorsolateral folds with the posterior portion offset medially. The skin of the dorsal surfaces is generally smooth, except for the smooth dorsolateral folds and sometimes smooth tubercles and short ridges between the dorsolateral folds. The venter is smooth. The head is longer than wide, with a pointed snout in dorsal view. The tympanum is large, with its diameter roughly equal to the diameter of the eye. Finger I is longer than Finger II. Fingers are obtusely pointed, with round subarticular tubercles. Hands have no supernumerary, accessory palmar, or plantar tubercles. No lateral ridge on fingers. Thenar tubercle elongate, palmar tubercle irregular, tending to bifid or trifid. Tips of toes obtusely pointed, not expanded. Toes extensively webbed. Webs are deeply incised between toes II-III-IV. Inner metatarsal tubercle is elongated and there is no outer metatarsal tubercle. Males have a brownish nuptial pad on outer surface of thumb base, and the forearm is hypertrophied in larger adult males. Males also have paired light-colored lateral vocal pouches, and paired round vocal slits. The vocal sacs are concealed when deflated, in a slit under the tympanum at the edge of the lower jaw (Savage 2002).

Coloration in life: Dorsum and upper surface of limbs are gray-tan or brownish to gray-green with large, frequently elongated dark spots outlined in a lighter shade. No dark eye mask is present. Supralabial light stripe is incomplete. Posterior thigh surface is mottled with dark and light. Undersurface is white. The iris is gold above and brown below (Savage 2002).

Similar species: Rana taylori can be distinguished from R. forreri by having broken dorsolateral folds (vs. continuous in R. forreri), and from species of Leptodactylus by having webbed toes (vs. webbing not present in Leptodactylus) (Savage 2002).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Costa Rica, Nicaragua

View distribution map in BerkeleyMapper.

Rana taylori is found primarily in the humid premontane and lower montane areas of upland Costa Rica (Meseta Oriental, the Meseta Occidental, and probably the Cordillera Central) at 1,000 - 1,862 m asl. Rarely is it found in the humid Atlantic lowlands (60 - 1,000 m asl), but it has been reported from scattered lowland localities of eastern Nicaragua to south-eastern Costa Rica (Savage 2002).

Life History, Abundance, Activity, and Special Behaviors
Rana taylori is a semi-aquatic species of ponds, swamps, and marshes, found mainly in upland rain forest (Savage 2002). This species is active both during the day and at night (Savage 2002). It breeds at night during the May-November wet season (Savage 2002). Males call while floating on the water (Savage 2002). Eggs are black and white, laid in a plinth, with one clutch containing about 1,000 eggs that are attached to aquatic vegetation (Savage 2002). The larvae develop in the wetlands (Bolaños et al. 2008).

Like other amphibians, R. taylori can harbor parasites: one study found digeneans (Gorgoderina megacetabularis, G. parvicava, and Haematoloechus meridionalis) and nematodes (Oswaldocruzia costaricensis, Subulascaris falcaustriformis, and Porrocaecum sp.) (Goldberg and Bursey 2007).

Larva
This species has giant larvae, reaching 82 mm in total length. The larval body is ovoid with a moderate, bluntly pointed tail and deep tail fins. The mouth is ventral with a small emarginate oral disc, finely serrated beaks, and 2/3 rows of denticles. A2 has a large gap above the mouth. A row of papillae is present around the lower half of the oral disc, with another on the upper lateral portion of the disc but none above the mouth. The eyes and nares are dorsal. The spiracle is midlateral and the vent tube is dextral. The larval body is dark brown, with a light brown tail having numerous tiny lighter spots (Savage 2002).

Trends and Threats
R. taylori may be threatened by loss of habitat due to deforestation. It may also be at risk from water pollution caused by runoff from agricultural pesticides. In addition, highland ranid populations in Costa Rica are vulnerable to chytridiomycosis, though it is unclear whether this is one of the species at risk (Bolaños et al. 2008).

Rana taylori is part of a species complex (the Rana pipiens complex) which makes it difficult to obtain accurate population data (Bolaños et al. 2008).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Local pesticides, fertilizers, and pollutants

References

Bolaños, F., Chaves, G., Savage, J., and Köhler, G. 2008. Lithobates taylori. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. . Downloaded on 04 March 2011.

Goldberg, S. R., and Bursey, C. R. (2007). ''Helminths of two species of frogs, Lithobates taylori and Lithobates vaillanti (Ranidae), from Costa Rica.'' Caribbean Journal of Science, 43, 65-72.

Savage, J. M. (2002). The Amphibians and Reptiles of Costa Rica:a herpetofauna between two continents, between two seas. University of Chicago Press, Chicago, Illinois, USA and London.

Smith, H. M. (1959). ''Herpetozoa from Guatemala. 1.'' Herpetologica, 15, 210-216.

Species Account Citation: AmphibiaWeb 2023 Rana taylori: Peralta frog <https://amphibiaweb.org/species/5166> University of California, Berkeley, CA, USA. Accessed Feb 4, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 4 Feb 2025.

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