Meeting Abstract

S8.6  Wednesday, Jan. 6  Rethinking the phylogeny of scleractinian reef corals: reconciling morphologic and molecular data in the families Faviidae and Mussidae BUDD, A.F.; University of Iowa ann-budd@uiowa.edu

Recent molecular phylogenies conflict with traditional scleractinian classification at ranks from suborder to genus, challenging morphologists to discover new characters that better agree with molecular data. Such characters are essential for including fossils in analyses and tracing evolutionary patterns through deep time. The present study evaluates traditional macromorphological characters and newer micromorphological and microstructural characters in 5 related families including Faviidae and Mussidae (more than1/3 of reef-building genera). Previous molecular analyses show that the 5 families are not monophyletic, but consist of 7 family-level clades, with one clade composed only of Atlantic faviids and mussids. Comparisons of Atlantic mussids and faviids with their Pacific counterparts show that: (a) the septal teeth of Atlantic mussids are formed by well-developed secondary calcification axes with limited thickening deposits, whereas the teeth of Pacific mussids are formed by weak secondary axes with extensive thickening; (b) the septal teeth of Atlantic faviids have transverse axes that cross the main septum axis, whereas the teeth of Pacific faviids are often multi-directional; (c) corallite walls in Atlantic faviids are mostly septothecal, whereas walls in Pacific faviids are trabeculo- or parathecal. Development of secondary axes are similar in Atlantic faviids and mussids. Phylogenetic mapping of morphologic characters on molecular trees indicate that micromorphological and microstructural characters are diagnostic of clades and subclades, but macromorphologic characters are not. Phylogenetic trees constructed using new micromorphologic and microstructural characters have relatively high bootstrap support, and are congruent with molecular trees.