title: Resetting the evolution of marine reptiles at the Triassic-Jurassic boundary.
abstract: Ichthyosaurs were important marine predators in the Early Jurassic, and an abundant and diverse component of Mesozoic marine ecosystems. Despite their ecological importance, however, the Early Jurassic species represent a reduced remnant of their former significance in the Triassic. Ichthyosaurs passed through an evolutionary bottleneck at, or close to, the Triassic-Jurassic boundary, which reduced their diversity to as few as three or four lineages. Diversity bounced back to some extent in the aftermath of the end-Triassic mass extinction, but disparity remained at less than one-tenth of pre-extinction levels, and never recovered. The group remained at low diversity and disparity for its final 100 Myr. The end-Triassic mass extinction had a previously unsuspected profound effect in resetting the evolution of apex marine predators of the Mesozoic.
authors.affiliation: School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, United Kingdom.
authors.forename: Philippa M
authors.initials: PM
authors.lastname: Thorne
authors.forename: Marcello
authors.initials: M
authors.lastname: Ruta
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Benton
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D017753:Ecosystem; D053476:Extinction, Biological; D008386:Marine Biology; D010163:Paleontology; D012104:Reptiles