Aequornithes (, from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''aequor'', expanse of water +

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''ornithes'', birds), or core water birds, are 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 ...

'' as "the least inclusive crown clade containing '' Pelecanus onocrotalus'' and '' Gavia immer''", that is, the last common ancestor of the great white pelican and the common loon, as well as its descendants, extinct and extant. The

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

of the group is currently supported by several molecular

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

studies. Aequornithes includes the

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 ...

s Gaviiformes, Sphenisciformes,

Procellariiformes Procellariiformes is an order (biology), order of seabirds that comprises four family (biology), families: the albatrosses, the Procellariidae, petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still call ...

Ciconiiformes Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae, and make up the order Ciconiiformes . Ciconiiformes previously included a number of other families, such as herons and ibise ...

Suliformes The order Suliformes (, dubbed "Phalacrocoraciformes" by ''Christidis & Boles 2008'') is an order of birds recognised by the International Ornithological Congress, International Ornithologist's Union. Regarding the recent evidence that the tradit ...

and Pelecaniformes. It does not include several unrelated groups of aquatic birds such as

flamingo Flamingos or flamingoes () are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbe ...

s and

grebe Grebes () are aquatic diving birds in the order (biology), order Podicipediformes (). Grebes are widely distributed freshwater birds, with some species also found in sea, marine habitats during Bird migration, migration and winter. Most grebes f ...

s ( Mirandornithes), shorebirds,

gulls Gulls, or colloquially seagulls, are seabirds of the subfamily Larinae. They are most closely related to terns and Skimmer (bird), skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gul ...

, and

auk Auks or alcids are birds of the family Alcidae in the order Charadriiformes. The alcid family includes the Uria, murres, guillemots, Aethia, auklets, puffins, and Brachyramphus, murrelets. The family contains 25 extant or recently extinct speci ...

s (

Charadriiformes Charadriiformes (, from '' Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water ...

), or the

Anseriformes Anseriformes is an order (biology), order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest f ...

(waterfowl). Based on a whole-genome analysis of the bird orders, the

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 ( Eurypygiformes) and the three species of tropicbirds ( Phaethontiformes) together styled as the Eurypygimorphae are the closest sister group of the Aequornithes, in a clade later named Phaethoquornithes.

Phylogeny

The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below is based on Burleigh, J.G. et al. (2015) and Stiller et al. (2024)Stiller, J., Feng, S., Chowdhury, AA. et al. Complexity of avian evolution revealed by family-level genomes. Nature (2024). https://doi.org/10.1038/s41586-024-07323-1 with some names after Sangster, G. & Mayr, G. (2021). The clade Feraequornithes was named by Sangster & Mayr, 2021 to include the Pelecanimorphae and Procellariimorphae to the exclusion of the loons ( Gaviiformes). They defined this clade in the ''PhyloCode'' as "the least inclusive clade containing '' Pelecanus onocrotalus'' and '' Procellaria aequinoctialis''".

References

{{DEFAULTSORT:Higher Waterbird Birds by classification Taxa named by Gerald Mayr Extant Maastrichtian first appearances