Inhaltszusammenfassung

The release vocalizations of four nominal neotropical toad taxa (Bufo achalensis, Bufo limensis, Bufo spinulosus, Bufo arenarum) which compose three sympatric species pairs, were quantitatively analysed and homologous call types statistically compared. The first three laxa are closely related members of the mainly Andean Bufo spinulosus species group in which advertisement calls are absent. The specific vocal repertoire consisted of a uniform, unpulsed release call and...The release vocalizations of four nominal neotropical toad taxa (Bufo achalensis, Bufo limensis, Bufo spinulosus, Bufo arenarum) which compose three sympatric species pairs, were quantitatively analysed and homologous call types statistically compared. The first three laxa are closely related members of the mainly Andean Bufo spinulosus species group in which advertisement calls are absent. The specific vocal repertoire consisted of a uniform, unpulsed release call and one (in B. arenarum, two) pulsed release trill(s) which were given either singly or in series of up to three single calls. The uniform call was similar in structure and dominant (= basic) frequency in all taxa and probably represents an unspecific acoustic signal which is used to avoid heterospecific amplexus between sympatric toads. The release trills significantly differed in most call features among the taxa and, using discriminant analyses, even single calls were correctly assigned to sympatric pairs of species. In contrast, calls of allopatric pairs of species were confounded at rates of up to 36% indicating that selection towards species-specific signals increases when different species live in sympatry. The release trills of two allopatric populations (Peru, Argentina) assigned to B. spinulosus were similar in structure, but nevertheless features of pulse train permitted an unequivocal distinction, suggesting a long-lasting independent evolution. The taxonomic significance of this finding remains to be evaluated in further investigations. The complex vocal repertoire also offered the opportunity to assess phylogenetic relationships among the taxa. The extra-Andean B. achalensis seems to be closer related to the Andean B. spinulosus than this species is to the widely sympatric B, limensis - a species with several primitive character states indicating an early separation from the ancestral stock. » weiterlesen» einklappen

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DFG Fachgebiet:
Zoologie

DDC Sachgruppe:
Tiere (Zoologie)