LM

Introduction

The images included here are all from Cretaceous sediments and further illustrate the variety of morphologies that can be observed in nannofossil species. By comparison, these forms are often more peculiar than those displayed by Tertiary forms. Holococcoliths and nannoliths sometimes assume bizarre geometric shapes including cones (Nannoconnus, Conusphaera), capsules (Metadoga), cubes (Micula, Liliasterities), gears (Eprolithus), fish hooks (Ceratolithina), rods (Microrhabdulus, Acuturris), and other unique patterns. Heterococcoliths are generally placed into two broad groups (muroliths and placoliths) and can show beautiful structures in the coccolith center sometimes displaying complex arrangements of bars, pores and platforms (Cretarhabdus).