Using bioacoustics tools to clarify species relationships: vocalization of Cycloramphus lithomimeticus (Anura Cycloramphidae), with a phylogenetic comparative analysis of genus based on call

Abstract

In anurans communities, vocalizations play a fundamental role in social interactions, being the most important behavioral modality of communication. Therefore, the description of acoustic signals is indispensable for understanding aspects of their evolutionary history. The Cycloramphus genus consists of 30 species allocated into five groups, of which only 19 have the vocalization described. Cycloramphus lithomimeticus is a small-sized frog belonging to the C. granulosus group. This poorly known species is associated with rock surfaces near waterfalls in Atlantic montane forests, restricted to the state of Rio de Janeiro, southeastern Brazil. Currently, it’s classified as Near Threatened species category of IUCN and many aspects of its natural history remain unknown. Herein, we describe the advertisement call of C. lithomimeticus extending its known geographical distribution and providing additional data on the natural history of the species. We recorded and analyzed 44 calls from 10 males of C. lithomimeticus. The advertisement call of C. lithomimeticus consists of a single pulsed note with 0.3–0.8 sec of duration, emitted sporadically, with an interval between calls of 27.5–226.3 sec, composed by 7–17 pulses emitted at a rate of 18–26/sec, with a peak frequency of 2062.5–3000 Hz. After defining the correspondence between structures for systematic purposes, we made a comparative analysis determined by establishing homology connections with other species of the genus. According to our dominant frequency evolutionary reconstruction, an evolutionary increase in frequency mainly occurred in the C. lithomimeticus species lineage from an ancestral dominant frequency of 1500 Hz of the clade with C. eleutherodactylus species group, C. granulosus species group, and C. fuliginosus species group. This study contributes to our knowledge about the biology of C. lithomimeticus, and our results provide basic data for further acoustic, taxonomic and ecological studies in the genus Cycloramphus.