River Kingfishers - Taxonomy

Taxonomy

The river kingfishers family Alcedinidae is one of nine in the order Coraciiformes, which also includes the motmots, bee-eaters, todies, rollers, ground-rollers, Cuckoo Roller and two other families of kingfishers. The rollers do not appear to be particularly closely related to the others groups, and the Coraciiformes are therefore probably polyphyletic. In the past, all kingfishers were placed in the Alcedinidae, but it became clear that the three subfamilies diverged early, and the Halcyonidae (tree kingfisher|tree kingfishers) and Cerylidae (water kingfishers) are usually now treated as full families, with the Alcedinidae as the basal lineage in the kingfisher clade.

The taxonomy of the family is uncertain at present: it includes 22 to 24 species in two to four genera. The uncertainty arises from two small African species. The African Dwarf Kingfisher is sometimes placed in the monospecific genus Myioceyx, and sometimes with the Pygmy Kingfishers in Ispidina. However, molecular analysis suggests that the Madagascar Pygmy Kingfisher is most closely related to the Malachite Kingfisher, and that the present arrangement into Alcedo and Ceyx may need to be reviewed as it seems not to reflect the actual relationships (for example, the Azure Kingfisher is closer to Ceyx erithacus).