Dicarinella imbricata (MORNOD 1949): First SEM documentation of the lost holotype and foraminiferal assemblage from the type horizon (Upper Cretaceous, Switzerland)

Abstract.: The foraminifer species Dicarinella imbricata, from the Upper Cretaceous of Switzerland, was established in 1949 by L. Mornod. The holotype was figured only by Mornod's drawings and the specimen was never made available. As the holotype was missing since a long time, it was considered as lost and a neotype was established. However, the holotype was recently found. We present here the first scanning electron microscope (SEM) documentation of the holotype. These data are compared with the original drawings of the holotype, the neotype and a paratype. In addition, we report a rich and diverse Tethyan planktonic foraminiferal assemblage from the type horizon, whose composition indicates a late Turonian ag

Internal pore measurements on macroperforate planktonic Foraminifera as an alternative morphometric approach

Because of the lack of genetic control on extinct species, the morphologic approach remains the only way of identifying fossil Foraminifera. In addition to comparative description of gross shell morphology, morphometry became more important in recent years and was extended to encompass the ultrastructure of the shells. In particular, some studies focused on porosity, as determined by the pore diameters plotted against the number of pores per given surface. However, taking into account the poor preservation and recrystallization, which often affects and characterizes fossil specimens, and/or the deficiencies connected to the interpretation of scanning electron microscope images, pore measurements are often distorted, limited in number and lacking precision, and thus unreliable. We demonstrate that, by measuring the pores from inside the shell and individually, it is possible to obtain numerous and precise data either on an individual basis or for statistical purposes. This study also suggests that in the Early Miocene Globigerinoides, which is generally strongly susceptible for dissolution, the dissolution proceeds from the external towards the internal side of the shell

Miocene shallow-water limestones from São Nicolau (Cabo Verde): Caribbean-type benthic fauna and time constraints for volcanism

Shallow-water limestones of presumed Late Cretaceous and Eocene age, interbedded with basaltic lavas, were described by earlier authors from São Nicolau in the northwestern part of the Cabo Verde archipelago. If confirmed, these ages would imply late Mesozoic shallow-marine and subaerial volcanic activity in the Cabo Verde archipelago, and document a geological history very different from that known so far from other Cabo Verde Islands, from which no subaerial volcanic activity before the mid-Cenozoic is known. Our re-investigation of the foraminiferal fauna indicates a Late Miocene age for the presumed Late Cretaceous and Eocene limestones. The hypothesis of a long-lived hot spot, active by the Early Cretaceous, and of a major island-building stage in the Cabo Verde Islands during this period, is therefore not supported by the present bio- or chronostratigraphic dat