Revealing the diversity of the genus Ulva (Ulvales, Chlorophyta) in southeastern Brazil, with a description of Ulva kanagawae sp. nov.

ABSTRACTThe green algal genus Ulva is one of the most widely distributed macroalgal genera. The taxonomy of Ulva is problematic due to its simple morphology. The study of the diversity of this genus has undergone great advances using molecular data, leading to changes in the taxonomic status of species, and the recognition of species complexes and cryptic species. Here we reassessed Ulva species from southeastern Brazil using molecular data. We recognized 10 taxa, among which only three previously reported species were confirmed by molecular data: U. compressa, U. lactuca and U. ohnoi, the latter recently recorded from insular waters in Fernando de Noronha Archipelago, northeastern Brazil. Our phylogenetic analyses and species delimitation methods strongly supported the establishment of Ulva kanagawae sp. nov. The species traditionally cited for southeastern Brazil, U. flexuosa, U. linza, U. rigida and U. paradoxa, proved to be misapplied names of U. tepida, U. aragoënsis, U. ohnoi/U. lactuca and U. torta, respectively. One taxon, Ulva sp., remains unnamed and needs further studies. Ulva chaugulei and U. tanneri, both considered here as cryptogenic species, are new occurrences for Brazil expanding their geographic distribution to the Atlantic Ocean and western Atlantic Ocean, respectively. In addition, our analysis of sequences from type materials revealed that U. pseudo-ohnoi is a heterotypic synonym of U. conglobata. This first systematic molecular study of Ulva species in Brazil points out that more extensive sampling is needed to reveal the true diversity of the genus in Brazilian waters.KEYWORDS: PhylogenyrbcLtaxonomytufA ACKNOWLEDGEMENTSWe thank Joel Campos De-Paula, Renan Oliveira, Érico Atílio Teles, Mutue Toyota Fujii, Cristina Aparecida Nassar, Mateus Henrique Oliveira Pinto, Luanda Soares, Fábio Nauer, Maria Irisvalda L. G. Cavalcanti, Helena R. Fragoso, Bruno Sandy and Souto Neto for field assistance.DISCLOSURE STATEMENTThere are no conflicts of interest to be declared by the authors.Supplementary InformationSupplemental data for this article can be accessed online at https://doi.org/10.1080/00318884.2023.2243433Additional informationFundingThis work was supported by São Paulo Research Foundation (FAPESP, 2018/06085-1) to VC, and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Productivity Fellowship (proc. 304141/2020-8) to VC. This study was financed in part by the Rio de Janeiro Research Foundation (Biota FAPERJ, E-26/110.019/2011) to MBB-B and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 (scholarships to VARC, NTM and SLAS).