The Herpetological Journal

Authors: Igor Gerolineto-Alves, Fernanda Sousa Santos, Ramon Cavalcanti & Wilian Vaz-Silva

Abstract: Communication in anurans occurs mainly through acoustic and visual signals, both of which are essential for reproductive success and territorial defence. Despite their importance, many visual behaviours remain poorly understood, particularly those associated with signalling. In this study, we present the first record of toe-trembling behaviour in Boana caiapo, an endemic species of the Brazilian Cerrado, and provide a comprehensive review of the different types of visual communication reported in anurans. Field observations were conducted in October 2024 in a gallery forest area in the municipality of Itapirapuã, Goiás State, Brazil, using nocturnal active searches and acoustic playback stimulation. Four adult males in reproductive activity were documented, all of which displayed toe trembling, characterised by rapid, arrhythmic tremors of the digits on both fore and hind limbs, without lifting the feet from the substrate. This behaviour occurred at intervals of one to three seconds and was observed in approximately 70% of the advertisement calls, suggesting a role in multimodal communication during courtship, particularly in environments with high levels of acoustic interference. Our literature review identified 29 types of visual signalling behaviours reported worldwide in anurans, distributed across 98 species and two genera from 17 families. Hylidae exhibited the highest number of species with visual displays, most frequently involving limb lifting and toe trembling, often associated with agonistic interactions and courtship. The behaviour observed in B. caiapo differs from that reported in some congeners, in which toe trembling is primarily linked to male-male agonistic encounters. Instead, in B. caiapo, this behaviour appears to be more closely associated with advertisement calling and mate attraction. These findings highlight the importance of documenting novel signalling strategies, as they expand our understanding of the behavioural plasticity and multimodal communication strategies of anurans under diverse ecological pressures.

Keywords: multimodal communication, agonistic interactions, courtship behaviour, Cerrado biome, Hylidae

Author: Eric E. Flores

Abstract: Coiba Island National Park (CNP) comprises an offshore archipelago of around 35 islands and islets off the coast of Pacific Panama, which separated from the mainland around 12,000–14,000 ya. Visual Encounter Surveys and pitfall traps were used in combination with occurrence data from Global Biodiversity Information Facility and published sources to assess the herpetological richness, and community assemblages between CNP and the mainland. Amphibian richness was lower in CNP (maximum 5 spp.) compared to the mainland (maximum 13 spp.), while reptile richness was similar between CNP (maximum 21 spp.) and the mainland (maximum 25 spp.). Based on the rarefaction curves the observed reptile species richness was underestimated. Therefore, it is plausible that more general biological surveys would yield more species in the future. The genus Oscaecilia and the Turniptail gecko Techadactylus rapicauda are new records for the herpetofauna of CNP. The amphibian and reptile communities were different between CNP and the mainland, but the pattern of data favours a positive relationship with heterogeneous vegetation, and a possible small-island effect on the herpetological assemblages. The actual herpetofauna of CNP may result not only from dispersion and vicariance but also from other elements and past anthropogenic factors that need to be investigated in more detail.

Keywords: Coiba Island National Park, biodiversity, herpetology, Panama

Author: Eric E. Flores