On the Genus Colaniella and its Biostratigraphic Significance

Fusulininan foraminifera are one of the most important index fossils from the late early Carboniferous to the Permian in having worldwide distribution and short stratigraphic range. But, in accordance with an increase of size and complexity of shells the areal distribution was successively more localized, and at the end of the Middle Permian the larger fusulines represented by the Verbeekinidae and the Schwagerininae of the Fusulinidae were almost extinguished....