Classical and biochemical taxonomy of some sargassum species from the seashore of Alexandria, Egypt

ABSTRACT

Five species of the brown algal genus Sargassum [S. natans, S. fluitans setifolium, S. galapagense and S. parvifolium] from the seashore of Alexandria, Egypt, have been studied for their taxonomy based on a cumulative taxonomic approach in which the authors considered both classical and biochemical criteria. The five species were compared through their morphology, anatomy pigment composition on TLC, pigment absorption spectra and five isozymal systems a- esterases. Alk, phosphatases, Ac. phosphatases, malate dehydrogcnases and leucine aminopeptidases. The whole represent nine taxonomic markers. Numerical clustering was used to translate the isozymal electrophoretic patterns into individual and average similarity matrices and dendrograms. Based on such a cumulative taxonomic approach, it was found that 1. The five species studied do have enough similarity to stand together within the genus Sargassum. None of them showed to be unique in markers. 2. S. fluitans and S. setifoltum are strongly tied together and could be considered as two varieties of the same species or belonging to sub-genus. 3. S. natan and S. parvifolium are the ones with least number of similar bonds with other species and each of them could stand as a gienuine species 4. S. galapagense proved to have a moderate number of similarity bonds with other species and could also stand as a species by itself. This work proves that relying on one or two taxonomic markers to establish an algal taxonomy is not enough and could be misleading