Miocene fossils from the southeastern Pacific shed light on the last radiation of marine crocodylians

Miocene fossils from the southeastern Pacific shed light on the last radiation of marine crocodylians Salas-Gismondi R. auteur aut IRD Ochoa D. auteur aut IRD Jouve S. auteur aut IRD Romero P. E. auteur aut IRD Cardich J. auteur aut IRD Perez A. auteur aut IRD DeVries T. auteur aut IRD Baby Patrice auteur aut IRD Urbina M. auteur aut IRD Carré M. auteur aut IRD text journalArticle eng text/pdf born digital access The evolution of crocodylians as sea dwellers remains obscure because living representatives are basically freshwater inhabitants and fossil evidence lacks crucial aspects about crocodylian occupation of marine ecosystems. New fossils from marine deposits of Peru reveal that crocodylians were habitual coastal residents of the southeastern Pacific (SEP) for approximately 14 million years within the Miocene (ca 19 to 5 Ma), an epoch including the highest global peak of marine crocodylian diversity. The assemblage of the SEP comprised two long and slender-snouted (longirostrine) taxa of the Gavialidae: the giant Piscogavialis and a new early diverging species, Sacacosuchus cordovai. Although living gavialids (Gavialis and Tomistoma) are freshwater forms, this remarkable fossil record and a suite of evolutionary morphological analyses reveal that the whole evolution of marine crocodylians pertained to the gavialids and their stem relatives (Gavialoidea). This adaptive radiation produced two longirostrine ecomorphs with dissimilar trophic roles in seawaters and involved multiple transmarine dispersals to South America and most landmasses. Marine gavialoids were shallow sea dwellers, and their Cenozoic diversification was influenced by the availability of coastal habitats. Soon after the richness peak of the Miocene, gavialoid crocodylians disappeared from the sea, probably as part of the marine megafauna extinction of the Pliocene. specialized Gavialoidea marine crocodylians phylogenetics biogeography longirostrine ecomorphs PACIFIQUE PEROU 064 034 Proceedings of the Royal Society B : Biological Sciences 289 1974 20220380 [10 ] 2022 0962-8452 https://www.documentation.ird.fr/hor/fdi:010085132 10.1098/rspb.2022.0380 0962-8452 [F B010085132] https://www.documentation.ird.fr/hor/fdi:010085132 https://www.documentation.ird.fr/intranet/publi/2022-07/010085132.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2022-07-01 2025-02-24 fdi:010085132 fre