THE PERMIAN CORAL NUMIDIAPHYLLUM - NEW INSIGHTS INTO ANTHOZOAN PHYLOGENY AND TRIASSIC SCLERACTINIAN ORIGINS

The Permian coral Numidiaphyllum, having an unusual septal arrangement and an aragonitic skeleton, has been classified in the Rugosa. The ty pe species of Numidiaphyllum shows high intraspecific morphological va riability and distinct granulation on septal faces. Ontogenetic develo pment indicates that corallites show hexameral septal arrangement and cyclic mode of insertion. The genus has no specific morphologies that deny scleractinian affinities. Numidiaphyllum is believed to have orig inated in sponge-algal reefs in the Permian tropics but possesses a ba sic scleractinian form which was already established in Early Palaeozo ic times. Whatever their variation might be, the zoantharians, which m ay be closely related to Numidiaphyllum, survived the end-Permian exti nction in 'deep-water' refuges as Permian holdovers, retaining their b ody plan, and they are possible scleractinian ancestors in the Triassi c. Scleractinia have no immediate phylogenetic relationship to Rugosa. This study provides evidence about Permo-Triassic anthozoan phylogeny in terms of Permian survivors and their relationship to Triassic scle ractinian origins.