Wall-hispidity and -perforation in Eocene planktonic foraminifera

SEM (Scanning Electron-Microscope) studies of Eocene planktonic foraminifera from Israel show that the hispidity of test surfaces is due to the presence of protuberances (tubercles, pustules, pseudospines) of the same type as those found in many other Cenozoic species which do not possess true spines and spine-bases. Relatively raised interpore areas may be due to flaring pore-funnel walls (residual ridges) or to externally protruding inflational features (built-up ridges). Pore size and especially the ratio between pore-diameter and interpore distance, together with type and distribution of wall surface features, facilitate the recognition of species groups and genera, as well as of evolutionary lineages.