title: Mass extinction of lizards and snakes at the Cretaceous-Paleogene boundary.
abstract: The Cretaceous-Paleogene (K-Pg) boundary is marked by a major mass extinction, yet this event is thought to have had little effect on the diversity of lizards and snakes (Squamata). A revision of fossil squamates from the Maastrichtian and Paleocene of North America shows that lizards and snakes suffered a devastating mass extinction coinciding with the Chicxulub asteroid impact. Species-level extinction was 83%, and the K-Pg event resulted in the elimination of many lizard groups and a dramatic decrease in morphological disparity. Survival was associated with small body size and perhaps large geographic range. The recovery was prolonged; diversity did not approach Cretaceous levels until 10 My after the extinction, and resulted in a dramatic change in faunal composition. The squamate fossil record shows that the end-Cretaceous mass extinction was far more severe than previously believed, and underscores the role played by mass extinctions in driving diversification.
authors.affiliation: Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA. nicholas.longrich@yale.edu
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Longrich
authors.forename: Bhart-Anjan S
authors.initials: BA
authors.lastname: Bhullar
authors.forename: Jacques A
authors.initials: JA
authors.lastname: Gauthier
mesh_terms: D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D053476:Extinction, Biological; D049690:History, Ancient; D008116:Lizards / Q000033:anatomy & histology / Q000502:physiology*; D009656:North America; D010163:Paleontology; D012911:Snakes / Q000033:anatomy & histology / Q000502:physiology*; D013997:Time Factors