title: The Origin and Diversification of Birds.
abstract: Birds are one of the most recognizable and diverse groups of modern vertebrates. Over the past two decades, a wealth of new fossil discoveries and phylogenetic and macroevolutionary studies has transformed our understanding of how birds originated and became so successful. Birds evolved from theropod dinosaurs during the Jurassic (around 165-150 million years ago) and their classic small, lightweight, feathered, and winged body plan was pieced together gradually over tens of millions of years of evolution rather than in one burst of innovation. Early birds diversified throughout the Jurassic and Cretaceous, becoming capable fliers with supercharged growth rates, but were decimated at the end-Cretaceous extinction alongside their close dinosaurian relatives. After the mass extinction, modern birds (members of the avian crown group) explosively diversified, culminating in more than 10,000 species distributed worldwide today.
authors.affiliation: School of GeoSciences, University of Edinburgh, Grant Institute, King's Buildings, James Hutton Road, Edinburgh EH9 3FE, UK. Electronic address: Stephen.Brusatte@ed.ac.uk.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Brusatte
authors.affiliation: Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China. Electronic address: jingmai@ivpp.ac.cn.
authors.forename: Jingmai K
authors.initials: JK
authors.lastname: O'Connor
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA. Electronic address: jarvis@neuro.duke.edu.
authors.forename: Erich D
authors.initials: ED
authors.lastname: Jarvis
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D025061:Dinosaurs / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D053476:Extinction, Biological; D005580:Fossils / Q000033:anatomy & histology; D010802:Phylogeny