CE02 - Terre vivante

Life during past super-warm climate events: evolutionary dynamics of Early Eocene mammals from Southwestern France – EDENs

EDENs: mammal evolution during past super-warm climate events

Evolutionary Dynamics of Early EoceNe mammals from Southwestern France

An Eocene perspective on future climate?

Investigating biotic responses to past warming events is of great interest for predicting the long-term consequences of anthropogenic climatic and environmental degradation on biodiversity loss. The study of the early Eocene (56-47.8 Ma) is of primary importance here as it represents the warmest deep time interval of the past 66 Myr and corresponds to a key period of the mammalian radiation (abrupt emergence, explosive taxonomic diversity, and rapid intercontinental dispersals of most extant mammalian orders). Climate of the early Eocene is punctuated by a series of rapid, short global warming events, known as hyperthermals (or Eocene Thermal Maxima, ETMs), and by a long-term global warming event, the Early Eocene Climatic Optimum (EECO, ~53-49 Ma). In terms of magnitude, the major ETM is the Paleocene Eocene Thermal Maximum (PETM, ~56 Ma), an event which is commonly considered to be the best paleoanalog of present day climate change. <br /><br />Studying the impact of ETMs and EECO on mammal evolutionary history requires a very precise chronological framework, long stratigraphic sequences, and an adequate, good enough fossil record before, during and after each warm episode. Such a situation is exceptional, and even if very interesting data exist for the Northern Hemisphere, they remain incomplete and disparate; we know almost nothing about Southern Europe.<br /><br />The project EDENs aims to study fossiliferous, long and quite continuous stratigraphic sections from Occitanie Region, Southern France where new and very significant data have been recently acquired by our team in the Corbières, Lauragais, Minervois and Montpelliérain areas. The sections yielded rich mammalian faunas but also other continental vertebrate (actinopterygians, chelonians, crocodiles, squamates) and floral assemblages documenting most of the early Eocene, from the PETM to the end of EECO. This context is unique in Europe. We will exploit such a rich fossil record and unique stratigraphic frame.

First, we will develop new integrated calibration techniques including chemostratigraphy, magnetostratigraphy, cyclostratigraphy and biostratigraphy to construct a precise time-constrained framework for mammal evolution. We can reasonably expect a temporal resolution on the order of a few tens to hundreds of thousands of years. Second, we will reconstruct paleoenvironmental dynamics in describing vegetation and structural, sequential and sedimentary depositional models, and in identifying key climate parameters (temperatures, seasonality, and humidity) using various approaches. Third, focusing on extinct (‘condylarths’, plesiadapiforms, creodonts, and herpetotheriid marsupials) and extant (artiodactyls, perissodactyls, primates, bats, eulipotyphlans and rodents) mammalian clades, we will describe pattern and timing of their evolution in performing systematic, phylogenetic, and paleobiogeographic studies. We will also analyze their patterns of diversity and disparity, evolution of body size, diet, and locomotion to research potential faunal turnovers, pulse of diversification, and acme of diversity across ETMs and EECO. In addressing these questions, EDENs will allow comparisons at regional to global scale, with potentially major implications for the future of mammal diversity and biogeography.

-

-

-

Investigating biotic responses to past warming events is of great interest for predicting the long-term consequences of anthropogenic climatic and environmental degradation on biodiversity loss. The study of the Early Eocene (56-47.8 Ma) is of primary importance here as it represents the warmest deep time interval of the past 66 Myr and corresponds to a key period of the mammalian radiation (abrupt emergence, explosive taxonomic diversity, and rapid intercontinental dispersals of most extant mammalian orders). Climate of the Early Eocene is punctuated by a series of rapid, short global warming events, known as hyperthermals (or Eocene Thermal Maxima, ETMs), and by a long-term global warming event, the Early Eocene Climatic Optimum (EECO, ~53-49 Ma). In terms of magnitude, the major ETM is the Paleocene Eocene Thermal Maximum (PETM, ~56 Ma), an event which is commonly considered to be the best paleoanalog of present day climate change.

Studying the impact of ETMs and EECO on mammal evolutionary history requires a very precise chronological framework, long stratigraphic sequences, and an adequate, good enough fossil record before, during and after each warm episode. Such a situation is exceptional, and even if very interesting data exist for the Northern Hemisphere, they remain incomplete and disparate; we know almost nothing about Southern Europe.

The project EDENs aims to study fossiliferous, long and quite continuous stratigraphic sections from Occitanie Region, Southern France where new and very significant data have been recently acquired by our team in the Corbières, Lauragais, Minervois and Montpelliérain areas. The sections yielded rich mammalian faunas but also other terrestrial vertebrate (actinopterygians, chelonians, crocodiles, squamates) and floral assemblages documenting most of the Early Eocene, from the PETM to the end of EECO. This context is unique in Europe. We will exploit such a rich fossil record and unique stratigraphic frame.

First, we will develop new integrated calibration techniques including chemostratigraphy, magnetostratigraphy, cyclostratigraphy and biostratigraphy to construct a precise time-constrained framework for mammal evolution. We can reasonably expect a temporal resolution on the order of a few tens to hundreds of thousands of years. Second, we will reconstruct paleoenvironmental dynamics in describing vegetation and structural, sequential and sedimentary depositional models, and in identifying key climate parameters (temperatures, seasonality, and humidity) using various approaches. Third, focusing on extinct (‘condylarths’, plesiadapiforms, creodonts, and herpetotheriid marsupials) and extant (artiodactyls, perissodactyls, primates, bats, eulipotyphlans and rodents) mammalian clades, we will describe pattern and timing of their evolution in performing systematic, phylogenetic, and paleobiogeographic studies. We will also analyze their patterns of diversity and disparity, evolution of body size, diet, and locomotion to research potential faunal turnovers, pulse of diversification, and acme of diversity across ETMs and EECO. In addressing these questions, EDENs will allow comparisons at regional to global scale, with potentially major implications for the future of mammal diversity and biogeography.

EDENs has been developed as a partnership between the Institut des Sciences de l’Evolution de Montpellier (CNRS/University of Montpellier/EPHE/IRD), Géosciences Montpellier (CNRS/University of Montpellier/University of the French Antilles), and Laboratoire Paléontologie Evolution Paléoécosystèmes Paléoprimatologie (CNRS/University of Poitiers). Several external collaborators and nonprofessional paleontologists are involved. EDENs also relies on the support of two projects of UNESCO Geoparks.

Project coordination

Rodolphe Tabuce (Institut des Sciences de l'Evolution de Montpellier)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

ISEM Institut des Sciences de l'Evolution de Montpellier
GEOSCIENCES MONTP. Géosciences Montpellier
PALEVOPRIM LABORATOIRE DE PALEONTOLOGIE, EVOLUTION, PALEOECOSYSTEMES, PALEOPRIMATOLOGIE

Help of the ANR 407,075 euros
Beginning and duration of the scientific project: December 2020 - 48 Months

Useful links

Explorez notre base de projets financés

 

 

ANR makes available its datasets on funded projects, click here to find more.

Sign up for the latest news:
Subscribe to our newsletter