Revision of the Cretaceous coral family Columastraeidae (Scleractinia)

摘要

The coral family Columastraeidae (suborder Faviina) is revised on the basis of its type genus and respective type species. The family encompasses colonial plocoid forms with compact radial elements that are arranged in regular hexameral symmetry. The radial elements are composed of medium-sized trabeculae. Together with the name-giving genus Columastrea ORBIGNY, 1849, the genera Brachyphyllia REUSS, 1854, Placocolumastrea REIG ORIOL, 1989, and Proplesiastraea OPPENHEIM, 1930 are assigned to the family. Two genera - Eocolumastrea and Nudacolumastrea - are established as new. Eocolumastrea is established for mainly Early Cretaceous species that were formerly assigned to Columnocoenia and afterwards preliminarily to Placocolumastrea. Nudacolumastrea is the only genus in the family that lacks a columella, but presents paliform lobes at the first septal cycle. All genera are revised on the basis of the types of their respective type species, except for Proplesiastraea. Possible species of all genera are listed. Ranges and evolution of the genera are discussed. The family occurs worldwide from the Valanginian to Maastrichtian. In particular, the genera Columastrea and Eocolumastrea are very abundant faunal elements.