A Comparison of Mating Calls Recorded around the Type Localities of Rana tagoi and R. neba (Amphibia: Anura: Ranidae)

Abstract

Two species of frogs endemic to Japan, Rana neba and R. tagoi, have previously been separated based on differences in the number of chromosomes and the dominant frequencies of their advertisement calls. However, through a comparison of advertisement calls around the type localities of both species, we found that interspecific differences are instead apparent in the fundamental frequencies, not in the dominant frequencies. Additionally, the calls of R. neba are more easily distinguished by their unique first notes, which can be differentiated by the strong frequency modulation, longer and fewer pulses, and lower pulse rate. Compared with R. neba, the calls of R. tagoi are composed of notes with similar acoustic structure, although the last note is longer in duration, contains more pulses, and has longer inter-pulse intervals than in the other notes in the call. Based on these results, we present a new acoustic diagnosis for R. neba and R. tagoi.