Micrhystridium nanum (Deflandre, 1945) Deflandre and Deflandre-Rigaud, 1965

Now Solisphaeridium nanum (an acritarch species). Originally Hystrichosphaeridium brevispinosum var. nanum, subsequently Baltisphaeridium nanum (an acritarch species), thirdly Micrhystridium nanum, fourthly Polygonium nanum (an acritarch species), fifthly (and now) Solisphaeridium nanum (an acritarch species); see also Baltisphaeridium brevispinosum var. nanum (an acritarch varietas; combination not validly published). This taxon was raised to specific
rank by Stockmans and Williere, 1962 as Baltisphaeridium nanum.
Tax. sr. synonym of Baltisphaeridium brevispinosum var. wenlockense (al. Salopidium wenlockense) Downie, 1959, according to Lister, 1970 and Turner, 1984.
Holotype: Deflandre, 1945, pl.1, figs.5-6
Age: Silurian