Ichthyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary - Université Claude Bernard Lyon 1 Accéder directement au contenu
Article Dans Une Revue Naturwissenschaften Année : 2014

Ichthyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary

Valentin Fischer
  • Fonction : Auteur
Henri Cappetta
  • Fonction : Auteur
Peggy Vincent
Geraldine Garcia
  • Fonction : Auteur
Stijn Goolaerts
  • Fonction : Auteur
Daniel Roggero
  • Fonction : Auteur
Xavier Valentin
  • Fonction : Auteur

Résumé

Mesozoic marine reptiles went through a severe turnover near the end of the Triassic. Notably, an important extinction event affected ichthyosaurs, sweeping a large part of the group. This crisis is, however, obscured by an extremely poor fossil record and is regarded as protracted over the entire Norian-earliest Jurassic interval, for the lack of a more precise scenario. The iconic whale-sized shastasaurid ichthyosaurs are regarded as early victims of this turnover, disappearing by the middle Norian. Here we evaluate the pattern of this turnover among ichthyosaurs by analysing the faunal record of two Rhaetian localities. One locality is Autun, eastern France; we rediscovered in this material the holotypes or partial `type' series of Rachitrema pellati, Actiosaurus gaudryi, Ichthyosaurus rheticus, Ichthyosaurus carinatus and Plesiosaurus bibractensis; a revised taxonomic scheme is proposed. The second assemblage comes from a new locality: Cuers, southeastern France. Both these assemblages provide several lines of evidence for the presence of shastasaurid-like ichthyosaurs in the Rhaetian of Europe. These occurrences suggest that both the demise of shastasaurids and the sudden radiation of neoichthyosaurians occurred within a short time window; this turnover appears not only more abrupt but also more complex than previously postulated and adds a new facet of the end-Triassic mass extinction.

Dates et versions

hal-02350701 , version 1 (06-11-2019)

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Valentin Fischer, Henri Cappetta, Peggy Vincent, Geraldine Garcia, Stijn Goolaerts, et al.. Ichthyosaurs from the French Rhaetian indicate a severe turnover across the Triassic-Jurassic boundary. Naturwissenschaften, 2014, 101 (12), pp.1027--1040. ⟨10.1007/s00114-014-1242-7⟩. ⟨hal-02350701⟩
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