List of fossil bird genera

Rather, reasons for the extinctions listed here are stochastic abiotic events such as bolide impacts, climate changes due to orbital shifts, mass volcanic eruptions etc.

The relationships of these taxa are often hard to determine, as many are known only from very fragmentary remains and due to the complete fossilization precluding analysis of information from DNA, RNA or protein sequencing.

Before the late 19th century, when minerals were still considered one of the kingdoms of binomial nomenclature, fossils were often treated according to a parallel taxonomy.

The higher-level groups of non-Neornithes are arranged based on the phylogeny proposed by Luis Chiappe,[2] updated and expanded to incorporate recent research.

The earliest birds with a modern pygostyle: a reduction and fusion of the tail vertebrae; possibly a paraphyletic group.

Two types of pygostyle are known, a rod-shaped one found in Confuciusornithidae, Enantiornithes and some non-avian theropods such as Nomingia, and a plowshare-shaped one, only known in the lineage leading to modern birds.

The taxonomy of this group is confusing; the name "Ornithurae" was first proposed by Ernst Haeckel in 1866 and has been revised in meaning several times since.

[7] Note that Holtz also included the genera Eurolimnornis, Holbotia, Palaeocursornis and Piksi as euornitheans, though they have since been re-identified as pterosaurs.

Gulls, auks, shorebirds The diatrymas, a group of huge flightless Paleogene birds of unclear affinities.

As presented here paraphyletic; the tropicbird lineage is not part of this group and relationships with Procellariiformes and Sphenisciformes require more research.

The "proto-birds" above are of some indeterminate basal position in the entire avialan (and paravian) radiation, but known from such diagnostic material that their relationships at the family level are known.

In contrast, the taxa here have a hypodigm that is usually just sufficient for giving them a valid scientific name, but not for phylogenetic purposes beyond classing them as pygostylians or more modern birds.