Description
Dorsal coloration consists of brown blotches or tan spots that are variable to uniform, and the ventral surface is yellow (Savage and Heyer 1968). Upper limb is barred, an ivory stripe extends from seat to heel, and yellow or brown melanophores are scattered on the plantar foot surface and anterior/posterior thigh. Some individuals have blue-purple coloration on the flank and yellow groin spots. Coloration may be confused with Sordida puma, but absence of dark groin and flank reticulum, and absence of distinct light and dark foot to tarsal stripe in H. pseudopuma is diagnostic. Individuals may also be confused with Smilisca sordida, but bright yellow groin spots and brown or yellow posterior thigh of H. pseudopuma are characteristic differences. The dorsum is relatively smooth and the ventral surface is granular, and a series of warts may be present along the lower arm. The iris is gold and the pupil is horizontal, the tympanum is distinct, and the snout is rounded and truncate with a median projection in dorsal outline. Vomerine teeth arise at the level of the posterior choanae and extend posteriorly. Prepollex is not protuberant, fingers are approximately one-third webbed (vestigal between I and II) and bear large discs. Toes are about two-thirds webbed, and bear discs smaller than those of the fingers. Males have internal vocal sacs that are paired and lateral, and brown nuptial asperities extending to the thumb's disc (all information from Savage and Heyer 1968). The subspecies H. pseudopuma infuncata tends to be slightly larger than H. pseudopuma pseudopuma, but more diagnostic is the bluntly round snout (due to structural differences in the underlying premaxillaries) and red flash of color found on the thighs and webbing of H. pseudopuma infuncata (Duellman 1970). Males range in size from 37.6 to 42.9 mm, and the slightly larger females measure between 41.1 and 45.6 mm (Duellman 1970).

The mating call may consist of a single note or a series of short notes, generally low and poorly modulated, with a repitition rate of 45 notes per minute (Duellman 1970).

Distribution and Habitat

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

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (7 records).

H. pseudopuma is common throughout Costa Rica and Panama, and found in both disturbed and undisturbed habitats (Crump 1991). The range stretches from Northwestern Panama through the cordilleras of Costa Rica, within moderate altitudes (Savage and Heyer 1968). Two subspecies are recognized, H. pseudopuma pseudopuma and H. pseudopuma infuncata, with the former occurring in the highlands of Costa Rica and the Pacific slopes of western Panama and the latter restricted to the Atlantic slopes of western Panama (Duellman 1970).

Life History, Abundance, Activity, and Special Behaviors
H. pseudopumais active throughout the year, foraging during the night. During the day they are found secreted in bromeliads or elephant-eared plants, and at night (when not breeding) they are found in small bushes and trees (Duellman 1970). The breeding season corresponds to the rainy season, running between May and October. H. pseudopuma breeds explosively following heavy rains, at which time they congregate at ephemeral ponds and pools, often completing breeding within 24 hours (Crump and Townsend 1990). Males call to females from the water, preferentially deep water, and females respond with apparent size-random mate choice (Crump 1991; Crump and Townsend 1990). There is a strong male-biased sex ratio (Crump 1991), and male-male competition (in the form of mating balls) has been observed during the breeding season (Crump and Townsend 1990). Females control the final sites of egg depostion, and Crump (1991) demonstrated that selection for oviposition sites occurred based on presence of tadpoles, water depth, and possibly density of eggs. Multiple small egg masses (each group usually less than 500 eggs) are deposited at several locations within a pond or puddle, attached to emergent and submerged vegetation, with a total of 1800-2500 eggs per female (Crump 1991).

Tadpoles primarily feed on plant matter and detritus found within the breeding pools (Crump 1990). In addition, H. pseudopuma tadpoles (generally 23-28 mm in total length with well-developed hind legs) opportunistically cannibalize both heterospecific and conspecific eggs and early hatchlings (Crump 1983). Controlled studies by Crump (1990) have demonstrated that H. pseudopuma tadpoles which fed on conspecifics weighed more than those fed on heterospecifics, an indication that some particular advantage is obtained from conspecific cannibalism. Tadpoles have shown some degree of phentoypic plasticity, metamorphosizing early in response to simulated pond drying (at the cost of smaller body size) as compared to more prolonged development in a constant environment (Crump 1989). Tadpole predation occurs naturally by several invertebrate species, including adult dytiscid beetles (Rhantus guticollis), odonate naiads (Aeshinasp. and Sympetrum nigrocreatum), and notonectids (Crump 1984).

Trends and Threats
Declines have been reported for populations within the Monteverde region of Costa Rica's Cordillera de Tilaran, where an unprecedented crash led to the decline of 25 of 53 amphibian species during 1990 (Pounds et al. 1997). Here, where H. pseudopuma was found in the hundreds throughout the 1980s, the maximum number found was 43, significantly below the precrash levels (Pounds et al. 1997). The causal explanations that have been proposed have focused climatic factors in a direct or synergistic manner. Pounds and Crump (1994) proposed several climate-based hypotheses for other frogs effected within the area (namely Bufo periglenes and Atelopus varius): the moisture stress, temperature stress, climate-linked epidemic, and the climate-linked contaminant pulse hypothesis. More recent studies have linked Monteverde's declines to more subtle, but cumulative weather changes caused by global warming. Particularly, Pounds et al. (1999) analyzed precipitation, air temperature, sea surface temperature, and stream flow patterns in relation to communities of tropical anurans, birds, and anoline lizards. Their conclusions resolved that it was not simply the effect of the El Niño/Southern Oscillation, as Pounds and Crump (1994) had earlier hypothesized, but rather a larger warming trend (this trend remained significant with the El Niño fluctuations included) which crossed a threshold in late 1980's and precipitated a broad tropical anuran decline. Declines were evident in the anoline lizard communities as well, and the tropical avian communities underwent significant restructuring.

Earlier studies noted the particular sensitivity of H. pseudopuma tadpoles to drying conditions. As Crump (1991) noted, the ephemeral nature of the breeding ponds is subject to evaporation, which often leads to complete egg dessication and total tadpole mortality. In addition, environmental conditions that confine tadpoles to shallow pools may cause significant stress. Laboratory experiments conducted by Crump (1989) demonstrated how tadpoles grown in shallow water took much longer to develop than individuals raised in deeper water, possibly resulting from overcrowding.

Possible reasons for amphibian decline

Subtle changes to necessary specialized habitat
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

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

References

Crump, M. L, and Townsend, D. S. (1990). ''Random mating by size in a neotropical treefrog, Hyla pseudopuma.'' Herpetologica, 46(4), 383-386.

Crump, M. L. (1984). ''Ontogenetic changes in vulnerability to predation in tadpoles of Hyla pseudopuma .'' Herpetologica, 40(3), 265-271.

Crump, M.L. (1983). ''Opportunistic cannibalism by amphibian larvae in temporary aquatic environments.'' The American Naturalist, 121, 281-289.

Crump, M.L. (1989). ''Effect of habitat drying on developmental time and size at metamorphosis in Hyla pseudopuma.'' Copeia, 1989(3), 794-797.

Crump, M.L. (1990). ''Possible enhancement of growth in tadpoles through cannibalism.'' Copeia, 1990(2), 560-564.

Crump, M.L. (1991). ''Choice of oviposition site and egg load assessment by a treefrog.'' Herpetologica, 47(3), 308-315.

Duellman, W.E. (1970). The Hylid Frogs of Middle America. Monograph of the Museum of Natural History, University of Kansas.

Pounds, J. A., Fogden, M. P. L., Savage, J. M., and Gorman, G. C. (1997). "Tests of null models for amphibian declines on a tropical mountain." Conservation Biology, 11(6), 1307-1322.

Pounds, J. A., Fogden, M. P. L., and Campbell, J. H. (1999). ''Biological response to climate change on a tropical mountain.'' Nature, 398(6728), 611-615.

Pounds, J. A., and Crump, M. L. (1994). ''Amphibian declines and climate disturbance: The case of the Golden Toad and the Harlequin Frog.'' Conservation Biology, 8(1), 72-85.

Savage, J. M., and Heyer, W. R. (1968). ''The tree-frogs (Family Hylidae) of Costa Rica: diagnosis and distribution.'' Revista de Biologia Tropical, 16(1), 1-127.

Species Account Citation: AmphibiaWeb 2009 Isthmohyla pseudopuma: Meadow Treefrog <https://amphibiaweb.org/species/921> University of California, Berkeley, CA, USA. Accessed Dec 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Dec 2024.

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