Davidharwoodia megaspina gen. et sp. nov. (Corethrales), a new fossil marine diatom genus from Mors, Jutland (early Eocene)

A taxonomic survey of the early Eocene diatomites of Mors has revealed a new member of the Corethrales, Davidharwoodia megaspina gen. et sp. nov., which is the first fossil Corethron-like diatom to possess backward-pointing spines. The new species is presumably heterovalvate, with a rounded pyramidal Type 1 valve bearing a single huge leaf-shaped spine (and corresponding large socket) in addition to the narrower spines, and a more elongate helmet-shaped Type 2 valve possessing spines of a different design and twice as many sockets of equal size. The genus can be distinguished from Micrampulla by lacking the large inflated structures emanating from the dome, from Praecorethron by a narrower marginal area and vertically placed sockets, and from Corethron by lacking hooked spines.