Phylogenetic Studies in Selected Blade-Forming Red Algae (Rhodophyta) from the Gulf of Mexico

The main objective of this doctoral research is the elucidation of the evolutionary relationships and taxon diversity within multicellular blade-forming red algae. This study explores convergent evolution of the foliose habit in red algae that grow in the deep waters of the Gulf of Mexico, and this investigation has resulted in a dramatic increase of blade-like species in the Kallymeniaceae, Rhodymeniaceae, Furcellariaceae, Solieriaceae, Halymeniaceae, and an undescribed family in the Solieriaceae-complex from the Gulf of Mexico, and worldwide. On the basis of comparative DNA sequence analysis of plastid- encoded rbcL, along with comparative morphological studies and reproductive structures of all taxa studies, two perforated foliose species of Kallymenia J. Agardh occur in the Gulf, a dominant species new to science going under the name "K westii" that grows throughout the basin, and K. westii Ganesan, so far confined to the northwestern and southwestern Gulf In addition, Pacific species of Callophyllis Kutzing from Chile that comprise both blade and non-blade taxa are included in this study to expand the geographic study area. A new species of Chrysymenia (Rhodymeniaceae) for the northwestern and southwestern Gulf of Mexico is recognized. Halarachnion Kutzing, a newly reported genus for the northwestern Gulf is represented by an undescribed species in the Furcellariaceae. Isolates from the Gulf of Mexico are more closely related to H. ligulatum (Woodward) Kutzing from the Atlantic Ocean than to H. latisimum from Japan. This is also the first report of the Furcellariaceae, a family in the Solieriaceae-complex, for the Gulf of Mexico. In the Solieriaceae-complex in the Gigartinales, Flahaultia is represented by F. tegetiformans Taylor from the Campeche Banks, and by a second, undescribed species from the northwestern Gulf. Anatheca is represented by an undescribed species growing in the northwestern and southeastern Gulf This new taxon is closely related to the generitype, A. montagnei Schmitz from Senegal. The presence of nine species of Halymenia, two undescribed species of Cryptonemia, and one putative new genus in the Halymeniaceae is recognized.