CYLINDROSPIRA, A NEW DIATOM GENUS FROM THE PALAEOGENE OF DENMARK WITH PALAEOECOLOGICAL SIGNIFICANCE

Abstract

A new diatom genus, Cylindrospira is described from the Fur Formation, an Upper Palaeocene to Lowermost Eocene ash-bearing diatomite from North Denmark long renowned for its rich and diverse fossil flora. Two forms have been found, the largest of which, Cylindrospira simsi is designated here as the type species. SEM observations reveal that the structure of this and the smaller forma, homàrmi, have broad similarities with the Cretaceous genus Gladius, the Mid Eocene-Oligocene genus Pyxilla, the Late Eocene—Recent genera Aidacoseira and Melosira, and the Cretaceous-Recent genus Hemiaulus, but have sufficient dissimilarities from these to warrant the erection of a new genus. Associated palynological and sedimentological evidence suggest a brackish, probably lagoonal palaeoenvironment. To date, only fully marine diatoms have been recorded from the Palaeocene.