Herpetology Notes, volume 8: 429-431 (published online on 12 August 2015)

Necrophagy on ornata (Anura: Bufonidae) by the crab Trichodactylus fluviatilis (Crustacea: Trichodactylidae) in Atlantic Rainforest mountains of state of Rio de Janeiro, southeastern Brazil

Juliana Segadilha1 and Thiago Silva-Soares2,3,*

The bufonid Rhinella ornata (Spix, 1824) is a Gómez et al., 2015). Necrophagy on R. ornata has not medium-sized nocturnal species, endemic of Brazil, been reported until now. distributed along the coast of Atlantic Rainforest from the The freshwater crab Trichodactylus fluviatilis Latreille, states of Espírito Santo to northern Paraná (Baldissera, 1828 is a nocturnal inhabitant of altitude streams, 2010; Frost, 2015). It is an abundant species that inhabits endemic of Atlantic Rainforest (Magalhães, 2003). The open and forested areas of mountains and coastal plains species has a wide distribution along the continental and (Haddad et al., 2008). Anurans are part of the diet of a island areas from the coastal basins of eastern Brazil large number of predators, as mammals, birds, reptiles and in the basin of the upper Paraná River (Magalhães, and many invertebrates (Duellman and Trueb, 1994) 2003). It has been recorded in almost the whole range of such as decapods crustaceans (McCormick and Polis, the Atlantic Rainforest, from the states of Pernambuco 1982). This latter taxon is, for instance, one of the main to Rio Grande do Sul (Magalhães, 2003). The T. predators among the invertebrates (Wells, 2007). fluviatilis crabs are considered omnivorous, feeding on According to Begon et al. (2007) “necrophagy” is the plant material, eggs, other crustaceans, mollusks and consumption of flesh from carcasses. Many carnivorous tadpoles (Magalhães, 2003; Mageski et al., 2013). They are opportunistic carcass consumers (facultative are important components of inland aquatic ecosystems, scavengers), taking advantage of carrion when it is where they act as organic matter processors, playing a available (DeVault and Rhodes, 2002). Despite of significant role in nutrient cycling (Cumberlidge et al., the large number of reports regarding as 2009; Lima et al., 2013). prey and predators, consumption of dead has We observed one female of T. fluviatilis feeding on a been frequently underestimated or minimized (Cortéz- dead adult female of R. ornata on 15th September 2014 at the district of Lídice, municipality of Rio Claro, state of Rio de Janeiro, southeastern Brazil (22.781618°S, 44.232212°W; Altitude ca. 660 a.s.l.). At the previous night, this female was observed in amplexus with a male, during egg-cord oviposition, having several (five ¹ Universidade do Federal do Rio de Janeiro, Museu Nacional, Departamento de Invertebrados, Laboratório de Carcinologia, to seven) other males emitting advertisement calls on Quinta da Boa Vista S/N, 20940-040, Rio de Janeiro, Rio de the surroundings, characterizing a reproduction event. Janeiro, Brasil. On the following night, a couple of R. ornata was found ² Instituto Nacional da Mata Atlântica, Museu de Biologia Prof. lifeless at the same spot, 30–40 cm apart from each Mello Leitão, Av. José Ruschi 4, Centro, 29650-000, Santa other and mingled to their egg-clutch. The female had Teresa, Espírito Santo, Brasil. its hind limbs eaten by an unidentified predator, and the 3 Universidade do Federal do Rio de Janeiro, Museu Nacional, crab was eating its externalized viscera (Fig. 1). Departamento de Vertebrados, Laboratório de Herpetologia, Quinta da Boa Vista S/N, 20940-040, Rio de Janeiro, Rio de The specimen of T. fluviatilis was collected and Janeiro, Brasil. deposited in the collection of the Laboratório de * Corresponding author e-mail: [email protected] Carcinologia of Museu Nacional/UFRJ (lot MNRJ 430 Juliana Segadilha & Thiago Silva-Soares

Figure 1. Dead adult female of Rhinella ornata being eaten by the scavenger crab Trichodactylus fluviatilis, recorded at the district of Lídice, municipality of Rio Claro, state of Rio de Janeiro, southeastern Brazil.

25195) with seven others specimens occasionally on another anuran species, the treefrog Scinax cf. collected at the study site. The specimen of R. ornata arduous at the Área de Proteção Ambiental do Mestre was collected, identified, and posteriorly discarded due Álvaro, municipality of Serra, state of Espírito Santo, to its stage of deterioration. southeastern Brazil. It was not possible to point out granular or poison glands secrete whether the amphibian was already dead (M. Mageski, compounds that usually present effective repellent pers. comm.), even though the record was assumed to function, affording protection from predators (Cardoso be a predation event. However, our record indicates and Sazima, 1977; Clarke, 1997). Species of family that T. fluviatilis probably acts as an opportunistic Bufonidae, including those of the genus Rhinella, and scavenger species, feeding on amphibians already produce toxic skin secretions through dermal granular dead. glands, which are located especially within parotoid Since T. fluviatilis and R. ornata have similar glands (Almeida et al., 2007; Felsemburgh et al., distributions, it is possible that T. fluviatilis often 2009). These toxins usually present effective repellent feeds on dead individuals of R. ornata. Therefore, function, affording protection from predators (Cardoso this study report an ecological interaction on organic- and Sazima, 1977; Clarke, 1997). Thus, the unidentified matter processing among a toad and a scavenger crab, predator that supposedly killed the toad probably enclosing an important event of the natural life cycle of avoided eating the non-palatable parts of R. ornata, i.e., both organisms. most of dorsal skin and the paratoid glands, to prevent intoxication (see Schaaf and Garton, 1970), leaving the remains to the crab. Mageski et al. (2013) reported T. fluviatilis feeding Necrophagy on Rhinella ornata by the crab Trichodactylus fluviatilis in Brazil 431

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Accepted by Fabio Hepp