ANATOMICAL STUDIES ON THE PHAEOPHYCOTA OF KARACHI COAST

Abstract

Thirty-six species of epilithic brown algae, with multicellular, foliaceous and thalloid organizations belonging to three classes, three orders, four families and fifteen genera of the phylum Phaeophycota have been collected from Manora, Hawkesbay, Buleji and Paradise Point, the coastal areas near Karachi (Pakistan) during March 2006 and June 2010. They were morphologically investigated, identified with the help of existing literature and taxonomically described. As a result of that three new species viz. Iyengaria nizamuddinii, Spatoglossum shameelii and S. qaiserabbasii were discovered and eleven species were described for the first time from the coast of Pakistan. The occurrence of Padinopsis is its first record of growth in the Indian Ocean. In the previously described species, several new characters and taxonomic variations were recorded. Later on the collected species were investigated anatomically in detail. For this purpose, the thalli were first studied in surface view. Then cross sections (CS) were obtained from apical middle and lower parts of the thalli and microscopically examined to understand mode of growth and morphogenesis of thallus. Wherever possible, the CS and longitudinal sections (LS) of stipe, holdfast or heptron were obtained, in several cases the marginal portion of the thalli were also studied. The anatomy of fertile parts was investigated to understand reproductive structures, their development and pre-fertilization changes. The information obtained was compared with the previously published descriptions and discussed in each species. In most of the cases new and much detailed information was obtained and several new anatomical features were discovered.