# Across Ancient Oceans: Mapping the Dispersal Routes of Asian Anthropoids to South America

Leny Montheil, Alexis Licht, Beard K Christopher, Grégoire Métais, Pauline Coster, Bram Vaes, Yannick Donnadieu, Erwan Pineau, Laurent Husson, Guillaume Dupont-Nivet

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## To cite this version:

Leny Montheil, Alexis Licht, Beard K Christopher, Grégoire Métais, Pauline Coster, et al. "Across Ancient Oceans: Mapping the Dispersal Routes of Asian Anthropoids to South America." 29 ème édition de la réunion des sciences de la Terre (RST 2025), Société Géologique de France (SGF), Oct 2025, Montpellier, France. pp.656271. insu-05361183

HAL Id: insu-05361183

https://insu.hal.science/insu-05361183v1

Submitted on 12 Nov 2025

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# Across Ancient Oceans: Mapping the Dispersal Routes of Asian Anthropoids to South America

Leny Montheil<fnref n="1" />, Alexis Licht*<fnref n="1" />, Beard K. Christopher<fnref n="2" />, Grégoire Métais<fnref n="3" />, Pauline Coster<fnref n="4" />, Bram Vaes<fnref n="1" />, Yannick Donnadieu<fnref n="1" />, Erwan Pineau<fnref n="1" />, Laurent Husson<fnref n="5" />, and Guillaume Dupont-Nivet<fnref n="6" />

## Résumé

Paleontological evidence reveals that between 40 and 35 million years ago, Asian anthropoid primates and rodents managed to disperse across vast stretches of open ocean-crossing over 500 km of the Tethys Sea to reach Africa and more than 1,500 km of the South Atlantic Ocean to arrive in South America. This talk explores a fundamental question in biogeography: how did these mammals traverse such vast seaways, and what routes might they have taken? We present a new high-resolution paleogeographic framework for the middle to late Eocene, focusing on the Neotethyan and Atlantic regions. This framework is built upon the latest plate kinematic reconstructions and paleogeographic datasets. Using this model, we assess how the arrangement and connectivity of landmasses along the Neotethyan margins may have facilitated faunal dispersals from Asia toward Africa and South America. Our reconstructions highlight two plausible island-hopping pathways across the Neotethys: one via southeastern Anatolia and another along Greater Adria. In the South Atlantic, we demonstrate that recent data support the partial emergence of the Walvis Ridge and Rio Grande Rise during this period. While these features may have served as stepping stones toward South America, this route would still have required crossing deep-water barriers more than 400 km wide. The precise mechanisms by which Asian primates reached South America remain elusive, but our findings help illuminate their possible migration pathways and bring us one step closer to solving this enduring paleobiogeographic puzzle.

**Mots-Clés:** Paleogeography, Cenozoic, Biogeography, Primates

<footnote n="1">¹CEREGE – CNRS : UMR7330, INRAE, Aix-Marseille Université - AMU, Institut de recherche pour le développement [IRD] – France</footnote>

<footnote n="2">²University of Kansas [Kansas City] – États-Unis</footnote>

<footnote n="3">³Muséum national d'Histoire naturelle – CNRS : UMR8067, CNRS : UMR7205, CNRS : UMRMECADEV7179, CNRS – France</footnote>

<footnote n="4">⁴Réserve naturelle géologique du Lubéron – Réserves Naturelles de France – France</footnote>

<footnote n="5">⁵Institut des Sciences de la Terre – Institut de Recherche pour le Développement, Institut National des Sciences de l'Univers, Université Savoie Mont Blanc, Centre National de la Recherche Scientifique, Université Gustave Eiffel, observatoire des sciences de l'univers de Grenoble, Université Grenoble Alpes – France</footnote>

<footnote n="6">⁶Géosciences Rennes – Université de Rennes, Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique, Observatoire des sciences de l'environnement de Rennes – France</footnote>

<footnote>*Intervenant</footnote>