Herpetology Notes, volume 14: 1151-1153 (2021) (published online on 01 September 2021)

New record of Thamnodynastes strigatus (: Dipsadidae) preying on Leptodactylus macrosternum (Anura: Leptodactylidae), with comments on antipredator mechanisms

Diego Henrique Santiago1,*, Thiago Silva-Soares2,3, and Ricardo Lourenço-de-Moraes4

The Thamnodynastes Wagler, 1845 comprises of frogs and is distributed throughout southern 21 species distributed throughout South America (Uetz North America, Central America, and South America et al., 2021), with 12 species currently known to occur (Frost, 2021). The White-lipped Frog, Leptodactylus in Brazil (Nogueira et al., 2019). Thamnodynastes is a macrosternum Miranda-Ribeiro, 1926, is a frog that genus of small, nocturnal, viviparous, mildly venomous inhabits swamps and ponds of open areas (Santos and opistoglyphous snakes that occupy a wide variety of Cechin, 2008), reaching 82 mm SVL in adult males and environments and habitats and, despite some recent 80 mm in females (Prado et al., 2000). Leptodactylus research, a significant amount of taxonomic uncertainty macrosternum has a brownish dorsal colour, paired vocal with these snakes remains (Franco and Ferreira, 2002; sacs, truncated snout, and posterior thigh region with a Rufatto et al., 2003; Bellini et al., 2013). uniform dark green colour (Santos and Cechin, 2008). The Coastal House , Thamnodynastes strigatus On 28 December 2019 at 09:32 h we observed an (Günther, 1858) is a semi-arboreal snake that frequently adult T. strigatus on the edge of a small stream inside hunts in aquatic environments and, as one of the largest a forest preying on a L. macrosternum, at Parque species in the genus, reaches up to 700 mm in snout–vent Primavera (protected area), Iporã Municipality, Paraná length (SVL; Franco and Ferreira, 2002; Bortolanza-Filho State, southern Brazil (24.0011°S, 53.6950°W; Datum et al., 2019). Its geographic distribution ranges throughout WGS84, elevation 317 m). The snake had already the southern and southeastern regions of Brazil, reaching captured the frog by biting it laterally on the body Argentina, Paraguay, and Uruguay (Franco and Ferreira, (Fig. 1A), making movements with the upper jaws to 2002; Nogueira et al., 2019). Reports on its natural inoculate the frog with its venom. In the attempt to break history indicate that T. strigatus is an active-search hunter free, the frog displayed limb interweave in synergy with that forages in search of prey, mainly amphibians, but death feigning as an antipredator mechanism (Ferreira et also includes in its diet fish, small mammals, snakes, al., 2019). This defensive mechanism had already been and lizards (Rufatto et al., 2003; Proença et al., 2015; reported in L. macrosternum (Lourenço-de-Moraes et al., Bortolanza-Filho et al., 2019). 2014). Limb interweave is an antipredator mechanism The genus Leptodactylus Fitzinger, 1826 comprises 83 that aims to display aposematic colouration, facilitating the spread of skin secretions, or even pretending to be injured, which can cause anxiety or injury in the predator and facilitate prey escape. In addition, a frogs may twist 1 Instituto Federal do Paraná, PPG Sustentabilidade, Campus onto its back, throwing its limbs across its body (see Umuarama, Rodovia PR 323, Km 310, Umuarama, 87507-014, Ferreira et al., 2019). Paraná, Brazil. 2 Museu de História Natural do Sul do Estado do Espírito Santo, After about 15 min, the snake repositioned itself to Universidade Federal do Espírito Santo, 29550-000, Jerônimo hold the front of the frog’s head and began to ingest Monteiro, Espírito Santo, Brazil. it (Fig. 1B). However, just after the ingestion process 3 Herpeto Capixaba, Vitória, 29090-090, Espírito Santo, Brazil. started, the frog used its hind legs to push the snake’s 4 Universidade Federal da Paraíba, PPG Ecologia e Monitoramento head away, which immediately made the snake stop Ambiental, Departamento de Engenharia e Meio Ambiente, the ingestion movement. Instead, the snake started Campus IV, Litoral Norte, Avenida Santa Elizabete s/n, Centro, moving its upper jaws again to inoculate more venom, Rio Tinto, 58297-000, Paraíba, Brazil. * Corresponding author. E-mail: diegosantiagoherpeto@hotmail. then continuing the ingestion process shortly thereafter. com Once again, the frog reacted by using its feet to move © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. the snake’s head away, and the snake repeated the 1152 Diego Henrique Santiago et al.

Figure 1. Interaction between the Coastal House Snake Thamnodynastes strigatus and the White-lipped Frog Leptodactylus macrosternum in Paraná State, southern Brazil. (A) The snake has bitten the frog on its side and inoculates it with venom. (B) The snake has repositioned itself in order to begin head-first ingestion of the frog. Photos by Diego Henrique Santiago. process of ceasing ingestion and moving the upper jaws Acknowledgements. We acknowledge the financial support from to inoculate yet more venom. Ingestion was complete by FAPES/VALE/FAPERJ (Grant No. 01/2015 – Pelotização, after approximately 40 min, when the snake left the Meio Ambiente e Logística, Process number 527/2016). This study was also financed in part by the Coordenação de Aperfeiçoamento stream edge and entered the forest. The specimens were de Pessoal de Nível Superior - Brasil (Finance Code 001). not collected. Anurans represent an essential dietary component of References various , snakes among the main predators, and some species of snakes are exclusively batrachophagous Bellini, G.P., Arzamendia, V., Giraudo, A.R. (2013): Ecology of (Vitt, 1983; Wells, 2007). To our knowledge, this is in subtropical-temperate South America. Herpetologica 69: 67–79. the first record of L. macrosternum as a prey item of Bortolanza-Filho, D., Lourenço-de-Moraes, R., Otani, M., Lemos, T. strigatus. In addition, we describe an antipredator G.F., Zawadzki, C.H. (2019): New records of the dipsadid snake mechanism used by L. macrosternum against predators, Thamnodynastes strigatus (Günther, 1858) preying on the characid an important defensive behaviour for this species. fish Astyanax bockmanni Vari & Castro, 2007 in the Atlantic Forest of southern Brazil. Herpetology Notes 12: 613–615. Thamnodynastes strigatus Preying on Leptodactylus macrosternum 1153

Ferreira, R.B., Lourenço-de-Moraes, R., Zocca, C., Duca, C., Beard, K.H., Brodie, E.D., Jr. (2019): Antipredator mechanisms of post-metamorphic anurans: a global database and classification system. Behavioral Ecology and Sociobiology 73: 1–21. Franco, F.L., Ferreira, T.G. (2002): Descrição de uma nova espécie de Thamnodynastes Wagler, 1830 (Serpentes, ) do nordeste brasileiro, com comentários sobre o gênero. Phyllomedusa 1: 57–74. Frost, D.R. 2021. Amphibian Species of the World: an Online Reference. Version 6.1 Available at: https://amphibiansoftheworld. amnh.org/index.php. Accessed on 18 August 2021. Lourenço-de-Moraes, R., Batista V.G., Ferreira R.B. (2014): Defensive behaviors of Leptodactylus chaquensis (Anura: Leptodactylidae). Herpetology Notes 7: 391–392. Nogueira, C.C., Argôlo, J.S., Arzamendia, V., Azevedo, J.A., Barbo, F.E., Bérnils, R.S., et al. (2019): Atlas of Brazilian snakes: verified point-locality maps to mitigate the Wallacean shortfall in a megadiverse snake fauna. South American Journal of Herpetology 14: 1–274. Prado, C.P.A., Uetanabaro, M., Lopes, F.S. (2000): Reproductive strategies of Leptodactylus chaquensis and L. podicipinus in the Pantanal, Brazil. Journal of Herpetology 34: 135–139. Proença, H.C., Lourenço-de-Moraes, R., Zawadzki, C.H. (2015): Natural history notes. Thamnodynastes strigatus (Corredeira). Diet. Herpetological Review 46: 651–652. Ruffato, R., Di-Bernardo, M., Maschio, G.F. (2003): Diet of Thamnodynastes strigatus (Serpentes, Colubridae) in southern Brazil. Phyllomedusa 2: 27–34. Santos, T.G., Cechin, S.T.Z. (2008): Amphibia, Anura, Leptodactylidae, Leptodactylus chaquensis: distribution extension in the state of Rio Grande do Sul, Brazil. Check List 4: 142–144. Uetz, P., Freed, P., Hošek, J. (2021): The Database. Available at: http://www.reptile-database.org. Accessed on 25 August 2021. Vitt, L.J. (1983): Ecology of an anuran-eating guild of terrestrial tropical snakes. Herpetologica 39: 52–66. Wells, K.D. (2007): The Ecology and Behavior of Amphibians. Chicago, Illinois, USA, The University of Chicago Press.

Accepted by Michael Jowers