Ornithologists and researchers studying dinosaur diversification have long puzzled over the evolutionary history of a group called the Neoaves, which encompasses nearly all the birds we have today except chickens, ducks, and ostrich-types. Now, after analyzing genome sequences from nearly 200 living bird species, researchers have a comprehensive view of the relationships between our modern birds.
The findings, published in Nature last week, fit with what’s known from the fossil record: A huge increase in bird diversity took place in the wake of the dino-dooming Cretaceous–Paleogene (or K–Pg, previously known as K–T) mass extinction 65 million years ago. And it happened fast too. More than 10,000 bird species evolved suddenly in just a few million years.
A team led by Yale’s Richard Prum and Cornell’s Jacob Berv analyzed more than 390,000 bases of genomic sequence data from each of our 198 living bird species – representing all major avian lineages – as well as two crocodilian groups.
Their family tree, called a phylogeny, distills Neoaves down to five major groups, uniting birds that we probably wouldn’t have grouped together: hummingbirds and swifts with nocturnal nightjars; pigeons, sandgrouse, cuckoos, and bustards; cranes; waterbirds and shorebirds; and landbirds. You can see how they’re all nestled together here and here.
All birds evolved from a group of dinosaurs that included T. rex and Velociraptor. All land birds – from backyard sparrows and woodpeckers to parrots and falcons – diverged early on from an ancestral, raptorial group that includes vultures and eagles. And since it was very rare for early birds to shift between terrestrial and aquatic lifestyles, the team thinks that nearly all water-based birds – such as penguins, flamingos, and seagulls (but not cranes) – shared a close, common ancestor. Additionally, today’s highly visual, diurnal hummingbirds, with their acute near-ultraviolet vision, evolved from species that had been nocturnal for 10 million years.
“This represents the beginning of the end of avian phylogeny,” Prum says in a statement. “In the next five or 10 years, we will have finished the tree of life for birds.”
A female ostrich (Struthio camelus) broods over her clutch in the rift valley of Kenya. This new study confirms that Ostriches are a member of one of the oldest groups of birds, the Paleognathae. Jacob Berv, Cornell University
Image in the text: The green wood hoopoe (Phoeniculus purpureus) is a large, up to 44 cm (17 in) long, tropical bird native to Africa. This new study places this species in a group called the Coraciimorphae. Jacob Berv, Cornell University