MORPHOLOGICAL VARIATION IN THE TIT-LIKE DACNIS (XENODACNIS PARINA): A CALL TO REVISE THE TAXONOMIC STATUS OF ECUADOR’S POPULATION

Xenodacnis is a specialized high Andean bird genus of which males are larger and show different feather coloration from females. However, sexual dimorphism has not been analyzed in detail yet. Distributed in Ecuador and Peru, Xenodacnis have long been considered as a single species genus, with three subspecies. Discovered in the 1980`s, the population in Ecuador has not been given a taxonomic identity so far. Thus, this study gathers morphological data from Xenodacnis throughout its distribution, and confirmed the morphological differences between sexes: males are significantly larger and heavier than females; but without consistent differences in bill size. Between populations, the research shows smaller individuals in the south, with size increasing towards the northernmost Ecuadorian populations. These results suggest that the taxonomy of the genus Xenodacnis should be revised and the population from Ecuador should have a proper taxonomic identity different from all previously described members of the genus