Observations on Late Cretaceous <i>Micrampulla</i> (Corethrales, Bacillariophyceae) from the Campbell Plateau (Zealandia), southwest Pacific Ocean

Late Cretaceous (late Campanian) diatom assemblages from the Campbell Plateau (Zealandia), southwest Pacific Ocean, obtained Deep Sea Drilling Project (DSDP) Leg 29 Site 275, contain well-preserved specimens of two enigmatic species currently assigned to genus Ktenodiscus; Micrampulla parvula originally described Maastrichtian-age Moreno Shale, California, and Pterotheca cretacea DSDP 275. In general, share a number common features with modern Corethron (domed valves, probable heterovalvate frustules, T-shaped serrated articulated spines, marginal sockets), but differ in location sockets (i.e. vertically at base valve dome not on rim), design spines sockets, hollow structure extending centre. Although hooked are absent, equivalent 1-spine 2-spine valves can be recognized these species. The recently Praecorethron same late Campanian sediments shares many Micrampulla, lacks inflated central structure. As result our studies, relevant subclass, order family definitions emended, as well those M. comb. nov., new family, Micrampullaceae fam. is erected distinguish ancient genera (Micrampulla Praecorethron) Corethron.