Bioacoustics of Rulyrana saxiscandens

Distribution and ecology. In addition to the four localities mentioned above, we have also obtained photographic records of this species from two sites in the Cainarachi valley north of Tarapoto ( Fig. 7 ): near the village of Santa Rosa ( 6°24'44.79"S , 76°19'2.09"W , 685 m ) and San Jose ( 6°25'14.67"S , 76°17'28.47"W , 517 m ). Considering these nominal taxa as a single species (see ‘Taxonomic remarks’), this species is distributed in the Cordillera Escalera, roughly between the cities of Tarapoto and Moyobamba, at elevations of 517–1047 m . This species occurs in habitats ranging from small creeks to torrential streams (e.g., Ahuashiyacu) to spray zones of waterfalls. This species has never been registered from heavily disturbed habitat, but does occur in secondary forest. At the type locality of Ahuashiyacu, we have noticed that individuals encountered in the streamside vegetation tend to be bright green whereas those collected from the rocks (particularly near the spray zone of the waterfall) tend to be dark green or black. Members of the genus Rulyrana are thought to be primarily rock-breeding species (Cisneros-Heredia et al. 2008), but we found that they often call from vegetation along rocky streams ( i.e. , our observations in both R. mcdiarmidi and R. saxiscandens ). Observed variation in coloration among individuals reflected microhabitat use when collected (vegetation vs. rocks), suggesting that the ability to change color may be a form of crypsis to aid in dynamic microhabitat use. Neither eggs nor tadpoles have been found from this species. Adults are active in a variety of microhabitats such as small trees (calling males have been heard as high as ~ 4 m ), streamside vegetation, and rocks along streams.