NOTA

Predation of Trachycephalus typhonius (Linnaeus, 1758) (Anura: Hylidae) by a juvenile Chacophrys pierottii (Vellard, 1948) (Anura: Ceratophryidae) in the Paraguayan Chaco

 

Diego Bueno Villafañe^1,2,3, Hugo Cabral Beconi^1,2,3, Arne Lesterhuis²

¹ Programa Nacional de Incentivo a Investigadores (PRONII). Consejo Nacional de Ciencia y Tecnología (CONACYT), (21)506223, Tte. 1ª Teófilo del Puerto, Asunción, Paraguay.

² Asociación Guyra Paraguay, +595 21 223 567, Av. Cnel. Carlos Bóveda, Parque Asunción Verde, Viñas Cué, Paraguay.

³ Instituto Investigación Biológica del Paraguay, Del Escudo 1607, Asunción, Paraguay.

Recibida: 05/04/16
Revisada: 29/04/16
Aceptada: 30/11/16

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ABSTRACT

Chacophrys pierottii is a medium-sized frog with generalist and opportunistic predation habits, and its diet includes mainly small vertebrates and arthropods. During a fieldtrip in Defensores del Chaco National Park (Alto Paraguay department, Paraguay), at the base of Cerro León we observed a juvenile male Chacophrys pierottii feeding on a juvenile Trachycephalus typhonius near to a temporary pond, formed by recent heavy rains. Our finding represents the first record of the arboreal frog, Trachycephalus typhonius as a prey item of C. pierottii. However, more data is necessary to determine if this event is an isolated case product of voracity, or T. typhonius juveniles on the ground are common prey during explosive reproduction.

Key Words: Trachycephalus; Ceratophrys; Predation; Chaco; Paraguay.

Chacophrys pierottii is a medium-sized frog with fossorial and nocturnal habits (Norman, 1994), and is endemic to Chacoan ecoregions of Argentina, Bolivia and Paraguay (Cei, 1980; Brusquetti and Lavilla, 2005). The species is a generalist and opportunistic predator and its diet includes small vertebrates and arthropods (Schalk et al., 2014). Here we report on the first record of predation on Trachycephalus typhonius by C. pierottii.

Our discovery took place in Defensores del Chaco National Park (Alto Paraguay department, Paraguay), at the base of Cerro León (20°25'57.97"S 60°19'3.31"W) on February 26, 2016 around 07:45- 08:00 h. A juvenile male Chacophrys pierottii (Snout-vent length (SVL)= 27.4 mm.) was found feeding on a juvenile Trachycephalus typhonius (SVL=19.2 mm) near to a temporary pond, formed as a consequence of recent heavy rains occurring in the area two days before. We also observed large activity of many other potential preys, including juveniles of Leptodactylus fuscus, Dermatonotus muelleri, Physalaemus spp., and Rhinella spp.

Upon capturing the individual of C. pierottii, we noted the presence of a hind limb emerging from its mouth (Fig. 1A). We carefully pull it to determine the identity of the prey, which turned out to be a juvenile of Trachycephalus typhonius in an early process of digestion (Fig. 1B). After prey extraction, we collected and fixed the predator.

Figura 1. A. Individual of Chacophrys pierottii found with a frog hind limb emerging from its mouth. B. Juvenile of Trachycephalus typhonius partially digested (white arrow) after being partially extracted from the mouth of C. pierottii.

Quantitative analysis of the diet of juveniles and adults of C. pierottii was summarized by Pueta and Perotti (2013) and Schalk et al. (2014) respectively. Both reported a variety of juvenile and adult prey items including arthropods and frogs, being Coleoptera and Hymenoptera the most abundant preys and with the highest index of relative importance, but finding frogs along with Hymenopterans, volume­trically dominant. Until now, the only frogs reported as prey of C. pierottii were species with terrestrial and/or aquatic habits such as Leptodactylus spp., Physalaemus spp. and also cospecifics (Pueta and Perotti, 2013). Our finding represents the first record of the arboreal frog Trachycephalus typhonius as a prey item of juvenile C. pierottii.

Amphibians represent common part of the diet of most the Ceratophryidae species (Schalk et al., 2014), but there are few records of these anurans feeding on the ones with arboreals habits. Among the terrestrial species, a juvenile Ceratophrys cornuta found palatable to Scinax rubra in isolated conditions (Duellmann and Lizana, 1994) and Schalk et al. (2014) reported a case of a metamorphosed Ceratophrys cranwelli (SVL = 30 mm) feeding on a recently metamorphosed tailed Phyllomedusa sauvagii at the edge of a pond, from where it was suggested he came out the previous night. The latter case resembles ours, suggesting an early voracity and opportunistic behavior, in which the availability of item preys determines in a degree the diet of these predators. However, more data is necessary to determine if this event is an isolated case product of voracity, or T. typhonius juveniles on the ground are common prey during explosive reproduction events.

Acknowledgments

The authors wish to thank Consejo Nacional de Ciencias y Tecnología (CONACYT) for founding support through the Programa Paraguayo para el Desarrollo de la Ciencia y Tecnologia (PROCIENCIA) for project 14-INV-209 and Guyra Paraguay for logistic support. DB and HCB also want to thanks CONACYT for funding support through the PRONII program. To the Secretaría del Ambiente for collection permit 126-2015.

 

Literature cited

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