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SPHENOPHRYNE - American Museum of Natural History

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2000 ZWEIFEL: PARTITION OF <strong>SPHENOPHRYNE</strong><br />

121<br />

Fig. 80. Waveforms <strong>of</strong> call notes <strong>of</strong> four species <strong>of</strong> Austrochaperina. A. A. derongo. B. A. guttata.<br />

C. A. rivularis. D. A. macrorhyncha. Scale markings are in 0.01-sec intervals.<br />

L. schlaginhaufeni (category 3) are comparable<br />

except that in the former, note utterance<br />

continues for minutes and varies in rate,<br />

whereas the latter species calls in discrete,<br />

individual units. The other category 2 species,<br />

A. derongo, A. macrorhyncha, A. rivularis,<br />

and A. guttata, certainly have no close<br />

relationship to L. dentata, nor do the other<br />

pulsed-note species in category 3, A. brevipes<br />

and S. cornuta, to each other or to L.<br />

schlaginhaufeni.<br />

Advertisement calls <strong>of</strong> these microhylids<br />

are invaluable for distinguishing among species<br />

and may yet yield useful information on<br />

interspecific relationships, but I remain dubious<br />

about utility at higher taxonomic levels.<br />

STRUCTURE OF PULSED NOTES:<br />

FOUR SIMILAR CALLS COMPARED<br />

Four species <strong>of</strong> Austrochaperina—derongo,<br />

guttata, macrorhyncha, and rivularis—<br />

have calls <strong>of</strong> common structure: prolonged<br />

series <strong>of</strong> short, harsh, pulsed notes that are<br />

superficially similar, at least to the human<br />

ear. Table 5 summarizes pertinent characteristics<br />

<strong>of</strong> their calls (but bear in mind that this<br />

is based on only one call from each <strong>of</strong> three<br />

individuals and two <strong>of</strong> another). A. derongo<br />

is distinguished by the relative brevity <strong>of</strong> its<br />

call and by the high number <strong>of</strong> pulses per<br />

call. A. guttata has the shortest note duration<br />

and the highest note repetition rate. A. macrorhyncha<br />

has a slow repetition rate <strong>of</strong> the<br />

longest notes, whereas rivularis, with a similar<br />

repetition rate, has notes little more than<br />

half as long. Thus, the calls differ in at least<br />

two quantities each. Whether the range <strong>of</strong><br />

dominant frequencies (ca. 2100–2800 Hz) is<br />

significant is uncertain.<br />

Examination <strong>of</strong> the internal structure <strong>of</strong><br />

the notes reveals other differences in addition<br />

to number <strong>of</strong> pulses (fig. 80). Two calls <strong>of</strong><br />

what evidently was the same individual <strong>of</strong> A.

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