Original paper

Taxonomy and distribution of the Early Cretaceous coral genus Actinastraeopsis

Löser, Hannes

Abstract

The poorly known Early Cretaceous coral genus Actinastraeopsis is revised on the basis of available type material. It includes six species (Cladophyllia birleyoe Gregory, 1899; Thecosmilia catalaunica Angelis d'Ossat, 1905; Enallhelia gracilis Orbigny, 1850; Stylosmilia organisans Orbigny, 1850; Actinastraeopsis phaceloides Sikharulidze, 1977; Actinastraeopsis sp.); most of them were formerly assigned to the genus Cladophyllia. Actinastraeopsis forms phaceloid colonies made of densely packed thin branches. These colonies may reach large dimensions and form bioherms measuring several meters in width and height. Actinastraeopsis specimens show a large variation in their calicular dimensions, whereas the number of septa is regular within colonies and shows little variation. Septal counts and calicular dimensions are mainly used to distinguish species. To cope with variation within Actinastraeopsis species, the available material was systematically measured and statistically analysed. About fifty samples from numerous worldwide localities ranging from the Hauterivian to the Middle Albian were included.

Keywords

scleractiniacoralsstatisticscretaceous