SPHENOPHRYNE - American Museum of Natural History
SPHENOPHRYNE - American Museum of Natural History
SPHENOPHRYNE - American Museum of Natural History
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2000 ZWEIFEL: PARTITION OF <strong>SPHENOPHRYNE</strong><br />
115<br />
Fig. 73. Outline drawings <strong>of</strong> sacral regions <strong>of</strong> Austrochaperina and Sphenophryne in dorsal view;<br />
scale bars marked in millimeters. A. A. rivularis, AMNH A88445. B. A. basipalmata, AMNH A129495.<br />
C. A. palmipes, AMNH A92805. D. A. derongo, AMNH A92794. E. A. blumi, UPNG 9959. F. S.<br />
cornuta, AMNH A92803.<br />
modulation within a note. A call is a unit <strong>of</strong><br />
vocalization that may consist <strong>of</strong> a single note<br />
(when the period between notes is long with<br />
respect to the note duration and <strong>of</strong>ten is irregular)<br />
or may comprise notes rapidly repeated.<br />
Multinote calls may occur as short<br />
bursts <strong>of</strong> sound or may continue for long periods,<br />
sometimes seemingly indefinitely.<br />
Subjectivity in classifying notes and pulses<br />
Fig. 74. Right lateral view <strong>of</strong> jaw musculature<br />
<strong>of</strong> Oxydactyla stenodactyla. Scale bar marked in<br />
millimeters.<br />
occurs when the amplitude variation <strong>of</strong> pulses<br />
(as seen in an expanded waveform) approaches<br />
or attains 100% but with little quiet<br />
space intervening. For descriptive purposes,<br />
it generally is best to let the ear dictate the<br />
classification in such cases.<br />
A conspicuous dichotomy in the calls lies<br />
between those in which the notes are pure,<br />
unpulsed tones, and those whose notes are<br />
pulsed, giving a harsher sound sometimes<br />
characterized as a chirp. Calls with notes (or<br />
pulses) too rapidly repeated to be resolved<br />
by the human ear are heard as a buzz; none<br />
<strong>of</strong> the species discussed here has this type <strong>of</strong><br />
call. The other major variable involves the<br />
organization <strong>of</strong> notes into calls. I identify<br />
three levels <strong>of</strong> increasing complexity: (1)<br />
calls consisting <strong>of</strong> a single note, which is repeated<br />
at intervals wide with respect to the<br />
duration <strong>of</strong> the note and is generally irregular;<br />
(2) calls including a train <strong>of</strong> similar notes<br />
repeated relatively rapidly and extending<br />
over long periods; (3) calls in which rather<br />
standardized groups <strong>of</strong> notes are uttered as<br />
units separated by silent periods <strong>of</strong> variable