White-throated Thrush (1 Viewer)

... Our study shows that Mesoamerican T. assimilis and T. a. daguae are highly distinct genetically and reciprocally monophyletic, with an ancient disjunction and therefore a distinct evolutionary history, and have clear phenotypic differences which suggest that T. daguae is a separate species from T. assimilis, although our geographic sampling was not sufficient to establish if the two taxa are disjunct or parapatric. Therefore, our data suggest that both taxa could be considered full species under various species concepts applied to bird taxonomy: they satisfy the evolutionary independence required by the evolutionary species concept (Wiley 1981) and the diagnosability criteria required by the phylogenetic species concept (see Sangster 2014), as well as the more integrative multiple criteria (especially the interplay of distributional relationships such as parapatry, allopatry, and diagnosability) that have been suggested for assigning species rank to bird taxa (e.g., Helbig et al. 2002). Further analyses of variation in other characters such as song and ecology (e.g., Ortiz-Ramírez et al. 2016) will be needed to clarify the taxonomic statuses of these forms.

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Turdus daguae (Dagua Thrush) of w. Columbia and w. Ecuador is considered a separate species from T. assimilis (White-throated Thrush) of Mexico to w. Panama, based mainly on its very different vocalizations (totally lacking the White-throated's mimidlike phraseology) but also on certain morphological considerations. The song of T. daguae actually resembles that of cis-Andean T. albicollis (White-necked Thrush) more than it does T. assimilis.

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