Plectrohyla insolita

Advertisement call of Plectrohyla insolita (Fig. 4A–D). We examined a total of three calls from three individuals of P. insolita recorded in a time lapse of 125 minutes at air temperature between 15–19.3ºC and 88–100% of relative humidity. The vocalization of Plectrohyla insolita is a short “click” call, consisting of 5 to 6 pulses during the first half of its duration, followed by a pulsatile structure in the second half (see Fig. 4D). The call is amplitude modulated with the peak occurring at the beginning of the call duration, depicting a triangular wave form (pointed right; see Fig. 4D). Call duration is 60 ± 10 ms (50–70 ms). Although we obtained only three calls during over two hours of recordings, subsequent auditory surveys of unrecorded individuals indicated that males call every 10–35 minutes. Calls exhibit no frequency modulation (Fig. 4B). The minimum frequency of the call is 1,291 ± 37 Hz (1,258 –1,332 Hz), the maximum frequency is 2,265 ± 435 Hz (1,763 –2,541 Hz), and the dominant frequency is 1,894 ± 172 Hz (1,722 to 2,067 Hz). Natural History of Plectrohyla insolita (Fig. 3D–E). The species is uncommon and calls sporadically (e.g. 1–2 individuals registered per night). During October 2019, we detected four calling males of Plectrohyla insolita between 20:43 and 01:00 h. One adult male (UCR 23564; Fig. 3D) was recorded calling from a bryophyte-covered branch at 2.25 m above the stream, while three uncollected individuals (not recorded) were observed calling at heights of approximately 5 m above the stream. During June 2022, we registered two calling males approximately at 21:35 h. One of the individuals (CZB-H 022) was observed on top of two joint egg masses with a total of 80–100 embryos on different developmental stages (Gosner stages = 22–25; CZB-H 022) positioned at approximately 2.5 m above the stream (Fig. 5B). The egg masses were laid on a bryophyte-covered branch of a fallen tree that crossed the stream bed from side to side. Embryos on the earlier stage of development in the clutch (stage 22) were located in the upper part of the egg mass, with the male on top of them, whereas more developed embryos (stage 25) were at the bottom part of the egg mass. The guarding male was calling at the beginning of our observations but it stopped calling due to our presence. The frog remained on top of the egg mass, changing its orientation to 90° in the vertical plane and to 60° in the horizontal plane. During nighttime surveys in October, 2019, air temperature was 15ºC and the relative humidity was 100%. During nocturnal surveys in June, 2022, air temperature ranged between 15–19.3ºC and the relative humidity varied between 88–100%.