Eurypygimorphae or Phaethontimorphae is a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

of birds that contains the orders Phaethontiformes (tropicbirds) and Eurypygiformes (

kagu The kagu or cagou (''Rhynochetos jubatus'') is a crested, long-legged, and bluish-grey bird endemism, endemic to the dense mountain forests of New Caledonia. It is the only surviving member of the genus ''Rhynochetos'' and the family Rhynoche ...

and sunbittern) recovered by genome analysis. The relationship was first identified in 2013 based on their nuclear genes. This group was defined in the ''

PhyloCode The ''International Code of Phylogenetic Nomenclature'', known as the ''PhyloCode'' for short, is a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the ...

'' by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing '' Phaethon aethereus'', ''

Eurypyga helias The sunbittern (''Eurypyga helias'') is a bittern-like bird of tropical regions of the Americas, and the Monotypic taxon, sole member of the family (biology), family Eurypygidae (sometimes spelled Eurypigidae) and genus ''Eurypyga''. It is found ...

'', and '' Rhynochetos jubatus''". Historically these birds were placed at different parts of the tree, with tropicbirds in Pelecaniformes and the kagu and sunbittern in Gruiformes. Some genetic analyses have placed the eurypygimorph taxa in the controversial and obsolete clade Metaves, with uncertain placement within that group. More recent molecular studies support their grouping together in Eurypygimorphae, which is usually recovered as the sister taxon to Aequornithes within Ardeae.Prum, R.O. ''et al''. (2015
A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing
Nature 526, 569–573.

References

Neognathae {{bird-stub