The Coraciiformes are a group of usually colorful birds including the kingfishers, the bee-eaters, the rollers, the motmots, and the todies. They generally have syndactyly, with three forward-pointing toes, though in many kingfishers one of these is missing. This is largely an Old World order, with the representation in the New World limited to the dozen or so species of todies and motmots, and a mere handful of the more than a hundred species of kingfishers. The name Coraciiformes means "raven-like", which is a misnomer. Specifically, it comes from the Latin language "corax", meaning "raven" and Latin "forma", meaning "form", which is the standard ending for bird orders.
Systematics
This order has been seen to be something of a mixed assortment, and the Coraciiformes may be considered as including only the rollers. All the other families would then be considered to representlineages of birds distantly related to Coraciiformes. This seems to be oversplitting, as most Coraciiformes indeed form a reasonably robust clade. Analysis of nDNAc-myc and RAG-1exon as well as mtDNAmyoglobinintron 2 sequencedata demonstrates that the Coraciiformes can be divided into a basal group that is not too distantly related to the Piciformes, and a derived suborder containing mainly kingfishers. The cuckoo roller's true affinities appear to lie elsewhere. The trogons and hornbills are either very basal lineages, or might be considered distinct own orders; the latter are apparently slightly closer to the rollers than the former. The entire group and the Piciformes are closely related to the Passeriformes. Several extinct coraciiform families are only known from Paleogene fossils. They probably belong to the basal group and are sometimes difficult to assign because they were even closer still to the Piciformes. In addition, there are some prehistoric genera which are likewise difficult to place into a family. At least the Eocoraciidae are very basal, but the Late EoceneGeranopteridae form a superfamilyCoracioidea with the extant rollers and ground-rollers already. A few prehistoric taxa of the present-day families have been described; see the family articles for details.
Taxonomic sequence
Unresolved
Genus Quasisyndactylus - alcediniform, basal?
Genus Cryptornis - bucerotid? geranopterid?
Family Primobucconidae, including Primobucco and Septencoracias
Coraciiformes gen. et spp. indet. PQ 1216, QU 15640
Genus Protornis - basal to motmotids and meropids?
A recent study suggest that the following families may belong to a separate order called Bucerotiformes. The results still in dispute though.
The Leptosomidae probably do not belong here. The trogons are sometimes placed here as a family Trogonidae. The Late EocenePalaeospizidae are sometimes also placed in the Coraciiformes, as are the Early to Middle Eocene Primobucconidae and the Middle Eocene to Early OligoceneSylphornithidae. The Primobucconidae at least indeed seem to belong here. Basal group
Family Eocoraciidae
Family Geranopteridae - includes "Nupharanassa" bohemica