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The Thai population of Kalophrynus pleurostigma interlineatus is distinct from the Bornean population of K. p. pleurostigma in advertisement call structure, i.e., notes pulsed in the former but unpulsed in the latter. This difference suggests that the Thai population is reproductively isolated from, or uses different recognition signals from, the nominal subspecies and should be regarded as a full species, K. interlineatus (Blyth, 1855). Taxonomic status of the population from Java requires further investigation.
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Matsui et al. (1996) studied this question.
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