Profesor Titular, Universidad de Barcelona

Professor of Earth and Planetary Sciences, University of Glasgow

Docent, Uppsala University

Professor of Earth Sciences, University of New England

Palaeontology Curator, Royal SK Museum; Adjunct Professor, Biology, U. of Regina

Emeritus research associate, Natural History Museum, London

Researcher (Paleontology) CICTERRA-CIPAL (CONICET-Universidad Nacional de …

Researcher, Department of Earth Sciences (Palaeobiology), Uppsala University

Universidad de Sonora

University of Colorado