Docidocercus gausodontus Montealegre-Z. & Morris, 1999

(2 males recorded) Two specimens were recorded, both at 23°C, both showing remarkable constancy in note interval. For one male (96-1), based on a sample of 24 successive calls from a longer sequence, the average call interval was 2.95 s with a coefficient of variation (ev) of only 2.4%. Each call of this male averaged 22 ms in duration. For the second male (96-2) mean call interval (n=19 successive calls) was 3.0 s (cv 2.7%). Each call (n=10) of 96-2 averaged 18.8 ms in duration.

Each call is one note: a single sustained pulse of about 20 ms duration (Fig. 35A), its waveform indicating one puretone frequency (Fig. 35B), its musicality readily apparent to the human ear if slowed on a tape recorder. In real time one hears an instantaneous 'pop'. But with tape speed reduced by a factor of 8, this signal ressembles the call of a common north american frog, the spring peeper.

The number of teeth on the file (96-1), 253 in a length of 2 mm, falls well short of the number of waves, about 400, observed in the uniform amplitude portion of the pulse. So it is impossible for the pulse to be generated on a single tooth per wave basis. Successive tooth-scraper mechanical interactions must maintain an exact phase to the ongoing resonant system to give rise to such a flat amplitude envelope.

The principal peak was the same for both recorded males: high-Qat 22.5 kHz (Fig. 35C). Second and third harmonics of this occur but both are >20 dB below the fundamental. There is a slight 600 Hz frequency modulation (FM) during the pulse. The principal peak begins at 23.1, drops to 22.5 by mid-pulse and then returns to above 23 again. [1]

References