PhD thesis: Tomas Getachew Bedane

NEWS/NOUVELLE

The CFEE is very happy to announce you that Tomas Getachew Bedane has successfully defended his brillant PhD. Congratulations ! The EHA team now includes a highly qualified Paleontologist. Great news !

Paleoecology and Evolutionary Dynamics of Neogene Elephantids of the Northern Rift (Awash and Turkana Basin, Ethiopia and Kenya) and Central Africa, Chad.

PhD defended on 12th December 2024, Poitiers University

By BEDANE Tomas Getachew

Summary: This dissertation investigates the paleoecology and evolutionary dynamics of Neogene Elephantids from East Africa’s Awash and Turkana Basins (Ethiopia and Kenya) and Central Africa (Chad), focusing on their dietary strategies and ecological adaptability. By integrating multiple analytical methods dental mesowear, dental microwear, dental calculus analysis, and stable isotope analysis the study reconstructs the feeding behaviors and habitat use of both fossil and modern Elephantid species across different regions and time periods. The findings reveal that Neogene Elephantids exhibited mixed feeding strategies, enabling them to adapt to diverse ecological niches that included a combination of browsing on trees and shrubs (C₃ plants) and grazing on grasses (C₄ plants). Dental mesowear analysis suggests long-term dietary flexibility, while microwear patterns provide insights into short-term feeding behaviors, showing variability linked to regional vegetation. Additionally, analysis of dental calculus revealed traces of both C₃ and C₄ vegetation, further corroborating their dietary diversity. Stable isotope analysis highlights a dietary shift over time, with fossil Elephantids predominantly grazing on C₄ grasses in open habitats, while modern species increasingly consumed C₃ browse in wooded environments. These findings underscore the ecological flexibility of Elephantids, which allowed them to adapt to changing landscapes and climatic conditions during the Neogene and Quaternary. By demonstrating how dietary plasticity influenced their survival and evolutionary trajectory, this research provides valuable insights into the broader patterns of mammalian evolution in response to environmental change.

Keywords:

Neogene Elephantids, Paleoecology, Evolutionary Dynamics, Northern Rift, Dental Calculus, Dental Mesowear, Dental Microwear, Stable Isotope

Jury:

Sally C. Reynolds, Professeure associée, Bournemouth Université, RU – Rapportrice

Tim D. White, Professeur, Université de Berkeley, USA – Rapporteur

Rahab N. Kinyanjui, Chercheuse Sénior, Max-Planck Institut & NMK Muséum, Allemagne – Examinatrice

Cécile Blondel, Maitresse de Conférence, UMR PALEVOPRIM, Poitiers, France – Examinatrice

Gildas Merceron, Directeur de Recherche, UMR PALEVOPRIM, Poitiers, France – Examinateur

William J. Sanders, Chercheur associé, Université du Michigan, USA – Examinateur

Kevin Uno, Professeure associé, Harvard University, USA – Examinateur

Jean-Renaud Boisserie, Directeur de Recherche, CFEE & UMR PALEVOPRIM, Addis Abeba & Poitiers – Directeur de thèse

Hassane T. MACKAYE, Maître de conférences, Université de Mango & N’Djamena, Tchad – Co-directeur de thèse