evolution of the acoustic communication system in members of the genus Adenomera (Anura: Leptodactylidae)
Subtitle: a comparative approach.
Published: 2004
Language: eng
Number of pages: 232
Description: Little is known about the relative contributions of phylogeny and the acoustic properties of habitats in shaping the evolution of acoustic features in anurans. Herein I explore this question with regards to three distinct Amazonian habitats where four sympatric congenerics occur. The Neotropical leptodactylid genus Adenomera is used as a model system in which to address this question.Acoustic features are used to identify species within this cryptic genus, phylogenetic analyses are conducted, and a phylogenetic hypothesis is used as a template upon which acoustic characters are mapped and macroevolutionary patterns of evolution can be inferred and interpreted. Acoustic data provide compelling evidence for much higher species richness in Adenomera  than currently acknowledged, with at least recognized 17 species as opposed to the eight nominal species presently accepted. Phylogenetic analyses include a combination of acoustic, morphological, and partial molecular data derived from the 12S and 16S ribosomal RNA genes. The monophyly of  Adenomera is generally supported, as are certain topological arrangements. Macroevolutionary patterns of call character evolution suggest general lability. Main carrier frequency, though, deserves special attention, in that the shift from a lower to higher frequency constitutes a puzzle for Adenomera  both in terms of habitat acoustics (lower frequencies carry farther than higher frequencies) and sexual selection (female anurans generally prefer males with lower frequencies). The derived nature of the main carrier frequency for most Adenomera is corroborated independently with acoustic information from aggressive signals.Measures of habitat acoustics in the three different Amazonian habitats where four sympatric Adenomera exist suggest that the physical properties of background noise, relative humidity and temperature are comparable across these three habitats.All signals attenuate and degrade with distance from broadcast source in all habitats, although attenuation may differ according to habitat.Combined evidence from phylogenetic analyses and experiments of environmental acoustics suggest that there are other evolutionary forces playing a larger role in shaping the evolution of acoustic characters.Finally, the discovery of increased species richness in this genus has important implications for assessments of amphibian populations, which have a bearing on conservation biology given the global phenomenon of declining amphibian populations.
Notes: Adviser: Glenn K. Morris.

Thesis (Ph.D.)--University of Toronto, 2004.

Electronic version licensed for access by U. of T. users.

Source: Dissertation Abstracts International, Volume: 65-05, Section: B, page: 2291.