GURGEL, CARLOS FREDERICO D1,2* and SUZANNE FREDERICQ2. 1Universidade Federal do Rio de Janeiro, CCS, Inst. de Biologia, Dept. Botânica, Ilha do Fundâo, Rio de Janeiro, RJ, Brazil, 21941-900; 2University of Louisiana at Lafayette, Dept. of Biology, POBox 42451, Lafayette, LA, USA, 50704-2451. - Three new species of Gracilariopsis (Gracilariales, Rhodophyta) from the Northwestern Atlantic.
A recent molecular phylogenetic study inferred from
chloroplast-encoded rbcL sequence analyses based on twenty specimens
of Gracilariopsis Dawson 1949 worldwide confirmed the monophyly
of the genus and revealed the existence of three new Caribbean species
(Gurgel et al., J. Phycol., submitted). Gracilariopsis sp. 1
collected in the Mexican Gulf of Mexico is sister to G.
tenuifrons. G. sp. 2 collected in Caribbean Panama (Colón
City) and Venezuela (Paraguana Península) is morphologically closely
related to G. panamensis. G. sp. 3 collected in
Venezuela (La Vela de Coro) is distinct from all other terete and
stringy species that characterize the genus by being a flat-foliose
taxon; it also shows a basal topology with uncertain phylogenetic
relationship to an undetermined species from Japan and China and to
G. heteroclada from the Philippines. The lack of clear-cut
vegetative and reproductive features among the species coupled with a
high degree of thallus plasticity may account for the fact that
genetically distinct species were not previously recognized as
taxonomically distinct. Our molecular and morphological studies reveal
that the diversity of Gracilariopsis species in the western
Atlantic and probably in the rest of the world is currently
underestimated. Morphologicaly detailed descriptions for all three new
species are provided.
Key words: algae, Gracilariaceae, Gracilariopsis, phylogeny, rbcL, Rhodophyta