Figure 6 in Taxonomic classification of the reef coral family Mussidae (Cnidaria: Anthozoa: Scleractinia)

Figure 6. Microstructural differences amongst the three major clades (XXI, XIX, XVII). All photos are of transverse thin sections at the same scale. The radiating linear plates are costosepta, which are connected in different ways to form corallite walls. Clade XXI (A-C) has costoseptal medial lines that are crossed by transverse structures (tc) such as carinae or clusters of calcification centres; corallite walls are predominantly either septothecal (Favia + Diploria + Pseudodiploria + Manicina subgroup) or parathecal. Clade XIX (D-F) is distinguished by well-developed thickening deposits (tk) and parathecal corallite walls, and widely spaced clusters of calcification centres. Clade XVII (G-H) is distinguished by small, closely spaced clusters of calcification centres (cl); wall structures range the gamut, and appear to be diagnostic of genus-level subclades. A, XXI, Favia fragum, FA1065, SUI122816, Bocas del Toro, Panama, Atlantic. B, XXI, Mussismilia hartti, YPM4516, Maria Farinha, Brazil, Atlantic. C, XXI, Isophyllia rigida, FA1009, SUI102752, Bocas del Toro, Panama, Atlantic. D, XIX, Lobophyllia pachysepta, USNM45515, Murray Island, Australia, Indo-Pacific. E, XIX, Homophyllia australis, USNM85709, Blyth Island, Australia, Indo-Pacific. F, XIX, Oxypora lacera, USNM93809, Madang, Papua New Guinea, Indo-Pacific. G, XVII, Merulina ampliata, UF2051, Palau, Indo-Pacific. H, XVII, Favites halicora, USNM90627, Philippines, Indo-Pacific. I, XVII, Hydnophora exesa, USNM83232, Marshall Islands, Indo-Pacific.