Cnidarians – Cnidaria

Abstract

Cnidarians, which show a remarkable diversity of morph- ology and lifestyles, are important as reef-constructors, predators, and parasites in marine ecosystems. Few data currently exist on the timing of the evolutionary events among major groups of cnidarians (~7 classes and ~25 orders) and some of these are associated with high levels of uncertainty. However, fossil evidence, and molecular esti- mates of divergence times among members of the subclass Hexacorallia (Class Anthozoa), indicate that past climate- change events have had a signifi cant impact on the evolu- tion of reef-building corals and related groups.