sentences:  Up to 20 species have been classified in the genus, but more recently the taxonomic placement of some of the traditional species has been questioned.Traditionally, the "Aquila" eagles have been grouped superficially as largish, mainly brownish or dark-colored booted eagles that vary little in transition from their juvenile to their adult plumages.Genetic research has recently indicated the golden eagle is included in a clade with Verreaux's eagle in Africa as well as the Gurney's eagle ("A. gurneyi") and the wedge-tailed eagle (clearly part of an Australasian radiation of the lineage).