Discussion on the calpionellid biozones and proposal of a homogeneous calpionellid zonation for the Tethyan Realm

Calpionellids are a group of planktonic microfossils usually occuring in large numbers in pelagic deposits from the upper lower Tithonian to upper Valanginian, and showing a fairly uniform stratigraphic distribution all over the Tethyan Realm and in the southeastern Pacific margin. A preliminary calpionellid scheme was first proposed by Jürgen Remane in 1963 and 1971 consisting of five zones and six subzones informally named: A (A1, A2 and A3),...