hear Fonozoo call

Description

DESCRIPTION:

DIAGNOSIS:

Compared to sister species P. nebulosum, P. guayapae lives at lower altitudes and has a smaller distribution range, being limited to the Chaco Seco ecoregion in Argentina. Pleurodema nebulosum, meanwhile, occurs in the Chaco Seco, Espinal, Estepa, Monte de Llanuras y Mesetas, Monte de Sierras y Bolsones, Pampa, and Puna ecoregions in Argentina. In saline environments and semidesert areas of central Argentina, the species ranges overlap (Ferraro and Casagranda 2009). Morphologically the species are nearly indistinguishable, except P. guayapae has a shorter and truncated snout, shorter legs, and a concealed tympanum (Cei 1980).

COLORATION: (In life and/or in preservative)

The dorsum is grayish in color and somewhat spotted, while the belly is white. The nuptial pads are brown. It is unclear whether this is in life or preservative (Cei 1980)

VARIATION: (if known)

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Argentina, Bolivia

View distribution map in BerkeleyMapper.

Pleurodema guayapae occurs in the Chaco region of Argentina, which is saline and dry. This region includes Parque Nacional Sierra de las Quijadas in the San Luis province and Reserva Provincial Chancaní in the Córdoba province, which are protected areas (Valetti et al. 2014, IUCN 2020). The elevational range is 80 - 520 m (IUCN 2020).

Pleurodema guayapae has also found ~1000 km to the north in the Izozog region of the department of Santa Cruz, Cordillera Province, Bolivia. More specifically, they were found in the towns of Aguaraigua, La Brecha, Ibasiriri, and Yapiroa along the Parapeti River. These areas are composed of low deciduous forest, low deciduous riverine forest, and secondary riparian habitats and lead to the swampy region of the Bañados del Izozog. Despite frequent surveys in the area between these two populations, P. guayapae has not been found between these two areas (De la Riva and Gonzales 1998).

Life History, Abundance, Activity, and Special Behaviors
Pleurodema guayapae is considered an explosive breeder (Valetti et al. 2014). The reproductive biology of P. guayapae is similar to that of P. nebulosum and hybrids between the species have been observed. However, the hybrids have a mating call that isolates them from both parental species (Cei 1980).

Pleurodema guayapae become active immediately after summer rains, which leave behind ephemeral freshwater ponds where breeding occurs. Males may call from either outside or inside of a pond, and calling activity has been observed to last for about 3 hours (Valetti et al. 2014). The mating call has been described as “the groaning sound of a car cornet” (Cei 1980). Based on call and the presence of juveniles, the Bolivian population is expected to breed from October to January or Feburary(De la Riva and Gonzales 1998).

Amplexus is axillary with amplected pairs floating in the water, along the pool’s edges, or out of the water (Valetti et al. 2014).

Members of the Leiuperidae subfamily like P. guayapae construct foam nests for their eggs to protect them from aquatic predators and desiccation (Schalk 2012). Foam nest construction begins once the amplected pair is in the water, alternating between phases of rest and activity. At rest, the pair is immobile and floating atop the water’s surface. The male’s feet are retracted, with his cloaca above that of the female. The activity phase begins when the male places his feet between the female’s thighs, into the water, with the cloacae of the male and female juxtaposed. The female will then spawn the eggs with the male lifting them above his cloaca using his tarsal tubercles. Then the male beats the foam with his legs in a rotational motion about 12 times. The male next opens his legs and cloaca, likely releasing sperm, and pushes the eggs toward the middle of the foam with his legs. The pair then enters the rest phase once more, alternating between rest and activity until the nest construction and egg-laying are complete. The nests are dome-shaped, being 6 - 9 cm in diameter and 1 - 3 cm tall, and float alone in the water, though they may be attached to vegetation. Nests may be communal, and communal nests consist of 2 - 5 interconnected nests (Valetti et al. 2014). The foam nest prevents the eggs from being exposed to the surface of the water and therefore predators like Ceratophrys cranwelli tadpoles, which are carnivorous. The foam nests may be insufficient in protecting the eggs from terrestrial predators, however, as the nests are open on top, leaving the eggs visible and exposed. The egg life stage is shortened in P. guayapae, though, reducing this risk. Eggs in laboratory conditions were observed to take 26 - 30 hours to hatch (Schalk 2012, Valetti et al. 2014).

Eggs are darker at the animal pole than the vegetal one and they are covered with a gelatinous capsule. Without this gelatinous layer, the average egg diameter is 1.44 mm. The average number of eggs per nest is 1137 (Valetti et al. 2014).

Leiuperines are known to show defensive behavior, which involves facing away from the predator, lowering the head, stretching the legs vertically, and displaying the macroglands to emulate a larger animal with big eyes. In other species, flash coloration may be shown when this position is assumed, however, P. guayapae lacks both the flash coloration and lumbar glands (Faivovich et al. 2012).

In Argentina, the species range overlaps with P. nebulosum and P. tucumana (Cei 1980).

In Bolivia, P. guayapae can be found in sympatry with Leptodactylus bufonius, Rhinella granulosus, Rhinella schneideri, and Physalaemus biligonigerus (De la Riva and Gonzales 1998).

Larva
Pleurodema guayapae larvae have large, sloping snouts. The spiracle is sinstral and nearly ventral (Cei 1980).

The dorsum and tail musculature are pale (Cei 1980).

Tadpoles are generally similar across the P. nebulosum group, though there are distinguishing characteristics. The snout shape is large and sloping in P. guayapae like in P. nebulosum but is short with nearly protruding nostrils in P. tucumana. Pleurodema guayapae also has a shorter tail length than that of P. tucumana, which has a tail almost twice the body length. The sinistral spiracle in P. guayapae is almost ventrally-located, whereas it is latero-ventral in P. tucumana (Cei 1980).

Trends and Threats
The explosive-breeding species is common throughout its range and is considered of "Least Concern" on the IUCN Red List. Aquatic egg predators and desiccation pose a threat to P. guayapae eggs, but no major threat to the species is known. The species occurs in Parque Nacional Sierra de las Quijadas in the San Luis province and Reserva Provincial Chancaní in the Córdoba province, which are protected areas (Schalk 2012, IUCN 2020).

The species may be tolerant of some human disturbance. In Bolivia, specimens were collected in seasonal ponds in or near towns (De la Riva and Gonzales 1998).

Comments

PHYLOGENETIC RELATIONSHIPS:

ETYMOLOGY (Origin or explanation of scientific name):

OTHER INTERESTING INFORMATION:

The identification of P. guayapae in Bolivia is perplexing as it is a disjunct 1000 km away from the most northerly Argentinian site and the area between the two sites has been extensively surveyed (De la Riva and Gonzales 1998).

References
Cei, J. M. 1980. Amphibians of Argentina. Monitore Zoologico Italiano. Nuova Serie, Monographia. Firenze 2: ixii + 609. 380-382.

De la Riva, I., and Gonzales, L. (1998). Sobre la presencia de Pleurodema guayapae Barrio, 1964 (Anura, Leptodactylidae) en Bolivia. Alytes 16(1–2), 68–76. [link]

Faivovich, J., Ferraro, D.P., Basso, N.G., Haddad, C.F.B., Rodrigues, M.T., Wheeler, W.C. and Lavilla, E.O. (2012). A phylogenetic analysis of Pleurodema (Anura: Leptodactylidae: Leiuperinae) based on mitochondrial and nuclear gene sequences, with comments on the evolution of anuran foam nests.” Cladistics, 28: 460-482. [link]

Ferraro, D. and Casagranda, M. (2009). Geographic distribution of the genus Pleurodema in Argentina (Anura: Leiuperidae). Zootaxa 2024(1), 33-55. [link]

IUCN SSC Amphibian Specialist Group. 2020. Pleurodema guayapae. The IUCN Red List of Threatened Species 2020: e.T57287A61414407. https://dx.doi.org/10.2305/IUCN.UK.2020-1.RLTS.T57287A61414407.en. Accessed on 03 October 2023.

Schalk, Christopher M. “Pleurodema guayapae. Egg predation.” Herpetological Review 43(4), 635. [link]

Valetti, A.V., Grenat, P.R., Baraquet, M., and Ludovico Martino, A. (2014). “Reproductive biology of Pleurodema guayapae (Anura: Leptodactylidae: Leiuperinae).” Revista de Biología Tropical, 62(1), 184-193. [link]

Species Account Citation: AmphibiaWeb 2024 Pleurodema guayapae: Guayapa’s Four-eyed Frog <https://amphibiaweb.org/species/3428> University of California, Berkeley, CA, USA. Accessed Dec 18, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 18 Dec 2024.

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