Geol. acta Geol. acta The early/middle Eocene transition at the Ésera valley (South-Central Pyrenees): Implications in Shallow Benthic Zones (SBZ) Rodríguez-Pintó A. Serra-Kiel J. Bernaola G. Barnolas A. Pueyo E. L. Tosquella J. Arbués P. Scholger R. 2022 research-article