Osmundea lata (M. Howe & W.R. Taylor) comb. nov. (Ceramiales, Rhodophyta) from the Brazilian south-eastern continental shelf

Specimens of Laurencia lata were dredged from the south-eastern Brazilian continental shelf near Cabo Frio (off the state of Rio de Janeiro) from a depth of 60 m, growing as epiphytes on the rhizoids if Laminaria abyssalis. Detailed examination of the vegetative and reproductive morphology of these specimens revealed anatomical characteristics belonging to the recently resurrected genus Osmundea. Such features include two periaxial cells per vegetative axial segment, spermatangial branches arising directly from apical and epidermal cells in the apical pit of branchlets (filament type), and tetrasporangia cut off from random epidermal cells. On the basis of these features. Osmundea lata (M. Howe & W.R. Taylor) Yoneshigue-Valentin, M.T. Fujii & Gurgel is proposed as a new combination for Laurencia lata. We present detailed observations of the vegetative and reproductive morphology of O. lata, and compare it with related species; its geographical distribution is also discussed

Marine Biodiversity in the Atlantic and Pacific Coasts of South America: Knowledge and Gaps

International audienceThe marine areas of South America (SA) include almost 30,000 km of coastline and encompass three different oceanic domains--the Caribbean, the Pacific, and the Atlantic--ranging in latitude from 12°N to 55°S. The 10 countries that border these coasts have different research capabilities and taxonomic traditions that affect taxonomic knowledge. This paper analyzes the status of knowledge of marine biodiversity in five subregions along the Atlantic and Pacific coasts of South America (SA): the Tropical East Pacific, the Humboldt Current, the Patagonian Shelf, the Brazilian Shelves, and the Tropical West Atlantic, and it provides a review of ecosystem threats and regional marine conservation strategies. South American marine biodiversity is least well known in the tropical subregions (with the exception of Costa Rica and Panama). Differences in total biodiversity were observed between the Atlantic and Pacific oceans at the same latitude. In the north of the continent, the Tropical East Pacific is richer in species than the Tropical West Atlantic, however, when standardized by coastal length, there is very little difference among them. In the south, the Humboldt Current system is much richer than the Patagonian Shelf. An analysis of endemism shows that 75% of the species are reported within only one of the SA regions, while about 22% of the species of SA are not reported elsewhere in the world. National and regional initiatives focusing on new exploration, especially to unknown areas and ecosystems, as well as collaboration among countries are fundamental to achieving the goal of completing inventories of species diversity and distribution. These inventories will allow accurate interpretation of the biogeography of its two oceanic coasts and latitudinal trends, and will also provide relevant information for science based policie

Two New Flat Species of Gracilaria (Gracilariales, Rhodophyta) From Brazil: G. Abyssalis sp. nov. and G. Brasiliensis sp. nov

A recent survey of the Brazilian Gracilariaceae (Rhodophyta, Gracilariales) flora aided by molecular-based phylogenetic analyses and comparative morphological data revealed two unidentified flat species of Gracilaria described here: G. abyssalis sp. nov. and G. brasiliensis sp. nov. Gracilaria abyssalis is a deep-water species characterized by a conspicuous holdfast; a long, branched, robust stipe; irregular to sympodial branching of the thallus; occasional presence of midrib; and an extensive range of broad blade morphologies. Gracilaria brasiliensis is a shallow intertidal species characterized by an inconspicuous stipe (< 1 cm), regular dichotomously branched thalli, and narrow blades and rounded apices. DNA sequence analyses of the chloroplast-encoded rbcL gene showed that flat species of Gracilaria in the western Atlantic belong to two distinct lineages. Maximum parsimony results placed G. brasiliensis as a member of the G. mammillaris clade with no support, while Bayesian results identified this species as a disntict new independent lineage. Furthermore, it was found that G. cuneata and G. curtissiae are recently diverged sister species and that rbcL phylogenetic distances among the morphologically distinct G. intermedia and G. yoneshigueana are quite small.Carlos Frederico D. Gurgel, Suzanne Fredericq, James N. Norris and Yocie Yoneshigue-Valenti