The Odontoanserae is a proposed

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 ...

that includes the family

Pelagornithidae The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family (biology), family of large seabirds. Their fossil remains have been found all over the wor ...

(pseudo-toothed birds) and the clade Anserimorphae (the order

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 ...

and their stem-relatives). The placement of the pseudo-toothed birds in the evolutionary tree of birds has been problematic, with some supporting the placement of them near the orders

Procellariformes Procellariiformes is an order of seabirds that comprises four families: the albatrosses, the petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still called tubenoses in English, procellariiforms are ...

and

Pelecaniformes The Pelecaniformes are an order of medium-sized and large waterbirds found worldwide. As traditionally (but erroneously) defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such ...

based on features in the sternum. In 2005 a cladistic analysis had found support in placing pseudo-toothed birds as the sister group to waterfowl. Evidence for this comes from shared characteristics in the skull such as lack of a crest on the underside of the

palatine bone In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxilla, they comprise the hard palate. Stru ...

and two

condyle A condyle (;Entry "condyle"
in

s on the mandibular process of the quadrate bone, with the middle condyle beakwards of the side condyle. In addition to that, both groups have similar features in their pelvic and pectoral regions. Furthermore, a 2013 study on the growth pattern and structure of the pseudoteeth in ''

Pelagornis ''Pelagornis'' is an extinct genus of prehistoric pseudotooth birds, a group of extinct seabirds. Species span from the Oligocene to the Early Pleistocene. Members of ''Pelagornis'' represent among the largest pseudotooth birds, with one species ...

mauretanicus'' shows more support of Odontoanserae as both groups have "soft rhamphotheca, or delayed hardening of the rhamphotheca." In addition to Pelagornithidae and Anseriformes paleontologists also have support in placing mihirungs (

Dromornithidae Dromornithidae, known as mihirungs (after Tjapwuring ''Mihirung paringmal'', "giant bird") and informally as thunder birds or demon ducks, were a clade of large, flightless Australian birds of the Oligocene through Pleistocene epochs. All are no ...

) and Gastornithids into this group, as they too also share anatomical features in the skull and pelvic bones with waterfowl. The mihirungs and the gastornithids are more derived than the pseudo-tooth birds and are closer to Anseriformes. One hypothesis is that diatrymas and mihirungs are successive sister groups to anseriforms and another hypothesis places mihirungs as crown anseriforms closely related to the screamers ( Anhimidae). Below is the general consensus of the phylogeny. However, a 2017 paper by Worthy and colleagues found an alternative phylogeny concerning Anserimorphae. By adding additional new characters, as well as incorporating several new taxa into established matrices, the authors have found gastornithids and mihirungs to be sister taxa which could be placed in the order

Gastornithiformes Gastornithiformes are an extinct order of giant flightless fowl with fossils found in North America, Eurasia, possibly Australia. Members of Gastornithidae were long considered to be a part of the order Gruiformes. However, the traditional conc ...

. In addition, they have found support that the family Vegaviidae (usually classified as crown anseriforms or their sister taxon) are more related to gastornithiforms than to anseriforms; accordingly, they have created the monotypic order Vegaviiformes. The authors did note the bootstrap support is weakly supported and several alternative phylogenies in their paper found gastornithiforms to be stem galliforms instead. These too were weakly supported as well. Below is a simplified phylogeny showing their one phylogeny supporting gastornithiforms as anserimorphs. In 2019 a new species ''

Conflicto antarcticus ''Conflicto antarcticus'' is an extinct species of stem waterfowl whose fossils were found in the early Paleocene López de Bertodano Formation of Antarctica, the only species of its genus. It is characterized by it slender body and long legs, ye ...

'' was described from Early

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

deposits in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. Known completely from associated bones from a single individual, Tambussi et al. (2019) incorporated the new taxon into a phylogenetic analysis using the matrix data from Worthy et al. (2017). Their results not only supported the sister grouping of vegaviids with gastornithids and mihirungs (which included Vegaviidae into Gastornithiformes), but also found two taxa, ''

Anatalavis ''Anatalavis'' is genus of prehistoric birds related to ducks and geese, perhaps to the magpie-goose (''Anseranas semipalmata'') in particular. Alternatively, it might have been a more basal lineage of Anserimorphae distinct from the living ...

rex'' and the tall, wading presbyornithids, traditionally placed as part of the anseriform crown, to be stem-anseriforms. Below is the Tambussi et al. (2019) phylogeny. In 2024, the

was recovered as a paraphyletic clade closer to basal

Galliformes Galliformes is an order (biology), order of heavy-bodied ground-feeding birds that includes turkey (bird), turkeys, chickens, Old World quail, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems ...

, while the

was recovered within or close to the

References

{{Taxonbar, from=Q25305236 Neognathae Extant Maastrichtian first appearances