Diversity of Chondracanthus (Gigartinaceae, Rhodophyta) on the Brazilian coast based on molecular and morphological evidences

Abstract

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 (

New records of Chondracanthus saundersii and Schottera koreana (Gigartinales, Rhodophyta) from Japan based on molecular and morphological analyses

“…2009; Rocha‐Jorge et al . 2018). This species is characterized by the presence of secondary attachments, which are compressed to flattened axes approaching 1 mm in width, and a looser medulla (Schneider & Lane 2005; Rocha‐Jorge et al .…”

“…This species is characterized by the presence of secondary attachments, which are compressed to flattened axes approaching 1 mm in width, and a looser medulla (Schneider & Lane 2005; Rocha‐Jorge et al . 2018). A comparison of morphological features among C. saundersii populations is shown in Table 1.…”

“…Our morphological observations of the new specimen collected from Mageshima agreed well with those of Schneider and Lane (2005) and Rocha‐Jorge et al . (2018). The outer cortex of the Japanese specimen is composed of three to four cells, whereas the outer cortex of C. saundersii comprises one to two cells (Schneider & Lane 2005; Rocha‐Jorge et al .…”

“…The outer cortex of the Japanese specimen is composed of three to four cells, whereas the outer cortex of C. saundersii comprises one to two cells (Schneider & Lane 2005; Rocha‐Jorge et al . 2018). The 0.3% rbc L divergence and morphological difference observed in the cortex may suggest that Japanese C. saundersii is a new species.…”