A guild classification system proposed for anuran advertisement calls

Abstract

Zoologists have widely acknowledged the utility of classification systems for characterising variation in anuran egg and clutch types, tadpole morphotypes, embryonic and tadpole development, amplexus types and reproductive modes. These classification systems have facilitated unambiguous communication between researchers, often working in completely different fields (e.g. taxonomy, ecology, behaviour), as well as comparisons among studies. A syntactic system, classifying anuran call guilds, is so far lacking. Based on examination of the calls of 1253 anuran species we present a simple, easy to use dichotomous key and guild system for classifying anuran advertisement calls – the call type most frequently emitted by anurans and studied by researchers. The use of only three call elements, namely clearly-defined calls, notes, and pulses, plus presence or absence of frequency modulation, allows assigning all currently known anuran advertisement calls to one of eight distinct call guilds defined here. This novel toolkit will facilitate comparative studies across the many thousand anuran species, and may help to unravel drivers of anuran call evolution, and to identify ecological patterns at the level of acoustic communities.