Cranial osteology and systematic considerations in Coccyzinae (Cuculidae)

Abstract

There is no consent whether the Coccyzinae is a monophyletic group and also about its position within Cuculidae. Furthermore, the osteology is poorly studied in this group. Thus, we described the cranial osteology of the 86 specimens belonging to 11 species in all four genera of Coccyzinae. The skulls are comparatively homogeneous in relation to the frontal, parietal, occipital, paraesphenoid regions and lacrimal and quadrate bones; however the upper jaw, squamosal region, palate and ectethmoid bones and mandible present morphologic variations mainly in generic level. These variations supply, a priori, some similarity relationships among the Coccyzinae taxa, mainly between Coccyzus and Hyetornis. The species within each genera are very similiar to each other, the exception is Piaya minuta that shows 11 diferent characteristics from other Piaya species. This result demands further investigations whether P. minuta should be considered within Piaya. The cranial osteological characters described here will be useful for a future cladistic analysis in order to test the hypotheses raised and also to solve the problematic classification of this controversial group.