Systematics of the Marine Red Algal Family Phyllophoraceae (Gigartinales, Rhodophyta) Based on Morphological and Molecular Evidence

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9903900Fredericq Red algae are exceptional for the great diversity in reproductive structures and for their complex life histories. One family of marine red algae, the Phyllophoraceae, in particular exhibits a wide range of life-history types, with corresponding diversity in morphological structures of the various diploid phases of the life cycle, and thus presents an opportunity to assess the phylogenetic importance of reproductive traits relative to the classification of the group. Type of life history and position of the reproductive structures on the plant body have traditionally formed the basis for identifying the 11 or so genera and ca. 100 species in the family; however, preliminary phylogenetic analyses inferred from DNA sequences of the plastid rbcL gene indicate a lack of correlation among the established taxa. This lack of correlation challenges the traditional taxonomy of the group. Dr. Suzanne Fredericq of the University of Southwestern Louisiana will use a comprehensive worldwide survey of the ca. 100 species of Phyllophoraceae (including the small group Petrocelidaceae) to generate new DNA sequence data from nuclear and plastid genes, and morphological data from detailed comparative studies of the same taxa. Integration of the molecular and morphological evidence will provide a phylogenetic framework for the entire group, from which can be reconstructed the sequence of critical developmental stages leading to the diverse "fruiting bodies" of these algae. Determination of the evolutionary relationships among the species of this family will also facilitate the study of their biogeographic distributions and migration patterns. As well, modern taxonomic monographs of the genera will be produced, incorporating the results of the new molecular evidence. An international network of colleagues is helping supply materials for the study, to be completed in collaboration with postdoctoral associate Juan Lopez-Bautista