Une étude résout le mystère de l'évolution de l'armure osseuse des reptiles

22 mai 2026

Rapporté par l'IA

Une nouvelle analyse évolutive a montré que les os cutanés des reptiles se sont développés indépendamment au sein de multiples lignées de lézards plutôt qu'à partir d'un ancêtre commun. Les chercheurs ont retracé ce trait sur 320 millions d'années en utilisant des fossiles et des méthodes informatiques. Les goannas australiens se distinguent par la perte de cette armure, qu'ils ont ensuite retrouvée des millions d'années plus tard.

L'étude, publiée dans le Biological Journal of the Linnean Society, a combiné des données provenant de 643 espèces vivantes et éteintes. Elle a déterminé que la plupart des lézards ont acquis des ostéodermes il y a plus de 100 millions d'années, au cours du Jurassique supérieur et du Crétacé inférieur. Ces structures osseuses ont probablement favorisé la survie dans un contexte de changements climatiques et de présence de prédateurs à l'époque des dinosaures tels que le Brachiosaurus et le Stegosaurus.

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