An ongoing phycological survey in the Laje de Santos Marine State Park (LSMSP) of São Paulo in southeastern Brazil revealed a previously undescribed species of Osmundea (Rhodophyta, Rhodomelaceae), which was found in the subtidal zone at a depth of 7 to 20 m. Morphological studies conducted on Osmundea specimens collected in the LSMSP revealed characteristics typical of the genus Osmundea, including two pericentral cells per each axial segment and tetrasporangia cut off randomly from cortical cells. The phylogenetic position of this species was inferred by analysis of chloroplastencoded rbcL gene sequences from 37 taxa, including one Rhodomelaceae and one Ceramiaceae as outgroups. The Brazilian species of Osmundea formed a well-supported clade with the 'Spectabilis' group from the coast of Pacific North America, composed of O. spectabilis, O. blinksii, O. splendens and O. sinicola. The present species, however, diverged greatly from the 'Spectabilis' group representatives (5.4-7.1%), which confirms that it constitutes a different taxonomic entity, herein proposed as the new species Osmundea sanctarum M.T. Fujii & Rocha-Jorge. This is the first report of a member of Osmundea related to the 'Spectabilis' group in the South Atlantic Ocean.

Laurencia marilzae is recorded for the first time from the western Atlantic Ocean; it was found in Laje de Santos Marine State Park, São Paulo, southeastern Brazil. The specimens were collected in the rocky subtidal zone from 7 to 15 m depth. The most distinctive characteristic of this species is the presence of corps en cerise in all cells of the thallus, including cortex, medulla, and trichoblasts. The phylogenetic position of the species was inferred by analysis of the chloroplast-encoded rbcL gene sequences from 43 taxa, using two other rhodomelacean taxa and two members of the Ceramiaceae as outgroups. Within the Laurencia assemblage, L. marilzae from Brazil and from the Canary Islands (type locality) formed a distinctive lineage sister to all other Laurencia species analyzed. Male plants are described for the first time. This study expands the geographical distribution of L. marilzae to the western Atlantic Ocean.

Based on morphological studies, four species of Chondracanthus Kützing were previously reported on the Brazilian coast: C. acicularis (Roth) Fredericq, C. elegans (Greville) Guiry, C. saundersii C.W.Schneider and C.E.Lane and C. teedei (Mertens ex Roth) Fredericq. In the present study, specimens of Chondracanthus were collected from intertidal and subtidal zones (up to 18 m depth); morphological, molecular and phylogenetic analyses were performed using DNA barcoding (cox1) as a tool in a survey of Rhodophyta biodiversity in São Paulo state. Unlike what we expected, C. saundersii is widely distributed, and many specimens were misidentified as C. acicularis or C. teedei before this study, suggesting the necessity of an accurate revision in the previous identifications of the species of Chondracanthus in Brazil. Tetrasporangial and cystocarpic structures of C. saundersii are described for the first time. Our results confirm that the utilization of cox1 sequences as DNA barcode is an efficient tool to complement morphological identification for species of the genus Chondracanthus. Keywords cox1 Á Phylogeny Á rbcL Á Taxonomy Abbreviations cox1 Cytochrome c oxidase GTR General-time-reversible model invariable sites and shape parameter of the gamma distribution MP Maximum parsimony NJ Neighbor-joining PP Posterior probability rbcL Gene coding for the large subunit of RUBISCO Electronic supplementary material The online version of this article (