Philippe Steemanshttps://orcid.org/0000-0003-1183-6324,^1,* Charles H. Wellmanhttps://orcid.org/0000-0001-7511-0464<sup>2,**

1</sup>aDépt. de Géologie, Unité de recherche PPP, Université de Liège, Campus du Sart Tilman, Quartier Ago
²bDept. of Animal & Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, She

^*Philippe Steemans is a senior researcher at the Belgium NFSR, Unit PPP (Paleobiogeology, Paleobotany, Paleopalynology), Liège University, Belgium. After a PhD thesis at University of Liège in 1986 on Lower Devonian miospores of the Western Europe, he received the title of Doctor. He is involved on palynology and its applications in the field of biostratigraphy, systematic, paleogeography etc. using miospores but also acritarchs and chitinozoans in collaboration with different specialists working in these research fields. He works on the Ordovician, Silurian and Devonian of many different regions like e.g. Saudi Arabia, North Africa, South America, China, Europe.
^**Charles H. Wellman is a professor of palaeobiology in the Deptartment of Animal and Plant Sciences, University of Sheffield. He received a BSc degree from the University of Southampton in 1987 and a PhD from Cardiff University in 1991. Charles’ PhD research involved a study of early land plant microfossils from Scottish Silurian-Devonian ‘Lower Old Red Sandstone’ deposits. Subsequently Charles' research has diversified to investigate various aspects of the colonisation of the land, including work on both living and fossil material, and a consideration of what lived on the land before the land plants.