Kingfisher - Taxonomy and Evolution

Taxonomy and Evolution

The taxonomy of the three families is complex and rather controversial. Although commonly assigned to the order Coraciiformes, from this level down confusion sets in.

The kingfishers were traditionally treated as one family, Alcedinidae with three subfamilies, but following the 1990s revolution in bird taxonomy, the three former subfamilies are now often elevated to familial level. That move was supported by chromosome and DNA-DNA hybridisation studies, but challenged on the grounds that all three groups are monophyletic with respect to the other Coraciiformes. This leads to them being grouped as the suborder Alcedines.

The tree kingfishers have been previously given the familial name Dacelonidae but Halcyonidae has priority.

The centre of kingfisher diversity is the Australasian region, but the family is not thought to have originated there. Instead, they evolved in the Northern Hemisphere and invaded the Australasian region a number of times. Fossil kingfishers have been described from Lower Eocene rocks in Wyoming and Middle Eocene rocks in Germany, around 30-40 million years ago. More recent fossil kingfishers have been described in the Miocene rocks of Australia (5-25 million years old). Several fossil birds have been erroneously ascribed to the kingfishers, including Halcyornis, from the Lower Eocene rocks in Kent, which has also been considered a gull, but is now thought to have been a member of an extinct family.

Amongst the four families the Alcedinidae are basal to the other two families. The few species found in the Americas, all from the family Cerylidae, suggest that the sparse representation in the western hemisphere resulted from just two original colonising species. The family is a comparatively recent split from the Halcyonidae, diversifying in the Old World as recently as the Miocene or Pliocene.