Intra-colony variability of calice characteristics in Recent Porites lutea Edwards and Haime, 1916: implications for fossil identification

Patterns of morphological variation in calice characteristics were investigated within a single colony of Porites lutea EDWARDS and HAIME, 1816 from the Northern Red Sea. Hierarchical cluster analysis and canonical discriminance analysis revealed four groups of calice morphs to occur within this colony. The most clearly discriminating variables were calice size and thickness of thecae, besides the thickness and length of septa and the development of pail. The development and degree of fusion within the ventral triplet as well as columella diameter had the lowest correlation with the discriminant functions. The most stable characters were the pattern of fusion within the ventral triplet and the development of the columella. Corallites from the upper face of the colony (vertical growth direction) were different from corallites on the lateral face of the colony (horizontal growth direction). For the identification of fossil Porites it is neccessary a) to obtain caches from several regions of the specimen in order to give a sample of corallite variability. b) It is neccessary to fully sample the pattern of septal fusion in the ventral triplet, as this is a stable character at a colony level.