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.