Tic, Tii and Trii calls: advertisement call descriptions for eight glass frogs from Colombia and analysis of the structure of auditory signals in Centrolenidae

In anurans, vocalisations are the main behavioural modality of communication. Hence, the description of acoustic signals in anurans is important for understanding many aspects of their biology. We describe for the first time the advertisement calls for eight glass frog species (Centrolene antioquiensis, ”Centrolene” robledoi, Nymphargus caucanus, N. chami, N. ignotus, N. rosada, N. spilotus, Sachatamia orejuela) and provide additional data on the recently described advertisement calls of Espadarana audax. In addition, we review the current knowledge of advertisement calls for all glass frog species (Centrolenidae). Based on the predominant temporal and the spectral structure, we identified three major types of calls in the family: 1) calls consisting of unpulsed short notes with amplitude modulation, similar to a ‘Tic’, 2) calls consisting of one long note (whistled) without amplitude modulation, similar to a ‘Tii’ and 3) calls consisting of pulsed or pulsatile notes, similar to a ‘Trii’. We mapped these acoustic characters in the context of the evolutionary history of Centrolenidae. Descriptions presented here offer evidence to recognise most centrolenid calls using measurable characters in the field or laboratory. As such, we hope to stimulate future studies based on bioacoustical analysis in this widespread and highly diverse Neotropical clade.