Mass extinction of lizards and snakes at the Cretaceous-Paleogene boundary

Nicholas R. Longrich, Bhart-Anjan S. Bhullar, Jacques A. Gauthier

Research output: Contribution to journalArticlepeer-review

125 Citations (SciVal)


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.
Original languageEnglish
Pages (from-to)21396-21401
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number52
Publication statusPublished - 26 Dec 2012


  • animals
  • biological evolution
  • body size
  • extinction, biological
  • history, ancient
  • lizards
  • North America
  • paleontology
  • snakes
  • time factors


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