Revision of sectionSetaceaof the genusBatrachospermum(Batrachospermales, Rhodophyta) with emphasis on specimens from Brazil

Abstract

This study evaluated the species level taxonomy and phylogenetic relationships among species of the section Setacea of the genus Batrachospermum. Molecular data (sequences of the plastid-encoded RuBisCO large subunit gene, rbcL; and the barcode region of the mitochondrial gene that encodes the cytochrome c oxidase subunit 1, cox1) were generated and morphological characters described for 15 populations from Brazil, Japan and Spain. The analyses of rbcL sequences revealed that section Setacea forms a well-supported clade, which was positioned close but clearly separated from some species of Batrachospermum usually called group 'Australasica'. Three well-supported clades were formed within the section: Batrachospermum sp. from Brazil; Batrachospermum atrum from Australasia, Europe and Asia and Batrachospermum puiggarianum from South America. The analyses of cox1 sequences revealed two well-supported groups: a large group with the sequences of B. puiggarianum from Brazil and a small group with one sequence of B. atrum from Spain and two sequences of Batrachospermum sp. from Brazil. The interspecific variation among these three species was high (38-71 bp, 3.0-5.5% for rbcL; 37-51 bp, 5.6-7.5% for cox1); whereas, sequence divergences within these three clades were much lower (0-33 bp, 0-2.6% for rbcL; 0-15 bp, 0-2.3% for cox1). The section is raised to genus (Setacea), and three species were recognized, including two previously described species (Setacea atra and Setacea puiggariana) that can be separated by either molecular and morphological data. A third species could not be distinguished from S. atra by morphological evidence but is clearly distinct based on divergence levels of both molecular markers used in this study (5.6-6.2% for rbcL; 3.0-3.4% for cox1) and is proposed as a new species (Setacea atro-brasiliensis) with the known geographic distribution restricted to Brazil.

Diversity of the genus <italic>Sheathia</italic> (Batrachospermales, Rhodophyta) in northeast India and east Nepal

“…Investigations focusing on the infrageneric taxa of the genus have been conducted to correct the paraphyly of Batrachospermum. As a consequence, several sections have been raised to the genus level: Kumanoa (former sections Contorta and Hybrida) (Entwisle et al 2009), Sheathia (former section Helminthoidea) (Salomaki et al 2014), Torularia (= Atrophycus, former section Setacea) (Rossignolo and Necchi 2016), Virescentia (formerly a section with the same name), Acarposporophycos (former section Acarposporophytum) and Visia (former section Aristata) (Necchi et al 2019a), Montagnia (Necchi et al 2019b).…”

“…Protocols for DNA extraction, polymerase chain reaction (PCR) amplification, purification and sequencing are the same as those described in our previous studies: Rossignolo and Necchi (2016), Necchi et al (2019aNecchi et al ( , 2019b. Two molecular markers were analyzed: the barcode region of the COI-5P, and the plastid-encoded rbcL.…”

First record of Nocturama (Batrachospermales, Rhodophyta) in South America, with the description of a new species N. novamundensis

“…1). The Nocturama clade was sister to a large clade formed by species of Sheathia, Nothocladus sensu Entwisle et al (2016) and Setacea sensu Rossignolo & Necchi (2016). Two groups with high support were formed within Nocturama, representing the type species (N. antipodites) and the Brazilian specimens.…”

Phylogeography of the freshwater red alga Batrachospermum viride‐brasiliense (Rhodophyta, Batrachospermales)

“…To resolve the paraphyly of the genus, some previously recognized sections have been raised to the generic level: Sheathia (Salomaki et al . ) and Setacea (Rossignolo & Necchi ). Alternatively, some authors lumped separate species and small sections in a wider genus, for example, Nothocladus sensu lato including Setacea and several Australasian taxa (Entwisle et al .…”

“…The red algal genus Batrachospermum has been shown to be paraphyletic in molecular phylogenetic studies and was recently treated as containing nine sections (Entwisle et al 2009). To resolve the paraphyly of the genus, some previously recognized sections have been raised to the generic level: Sheathia (Salomaki et al 2014) and Setacea (Rossignolo & Necchi 2016). Alternatively, some authors lumped separate species and small sections in a wider genus, for example, Nothocladus sensu lato including Setacea and several Australasian taxa (Entwisle et al 2016).…”