Abstract

The same specimens of Neobiscutum romeinii, Neobiscutum parvulum and Cruciplacolithus primus, with an average size of 2.0 mu m and deriving from the "type locality" of the Maastrichtian stage at ENCI quarry near Maastricht, The Netherlands, were documented both under the light microscope (LM) and the scanning electron microscope (SEM). The SEM micrographs with magnifications between 20K and 40K allow a precise recognition of all taxonomically relevant data. The LM illustrations, on the other hand, show little specks in most cases which do not always allow a correct classification. The limit of useful and accurate LM analysis is given by coccolith specimens with sizes over 2.5 mu m. It is therefore necessary to use a SEM when researching smaller coccoliths. The variation of small Neobiscutum and Cruciplacolithus species is relatively high and the existing taxonomic classification seems still doubtful. A modified technique for SEM/LM same-specimen-interchange was applied in order to perform successful microscopy.

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