Reappraisal of nine species of Martensia (Delesseriaceae, Rhodophyta) reported from Korea based on morphology and molecular analyses

Abstract

Previous taxonomic studies reported that nine species of Martensia (i.e., Martensia albida, Martensia australis, Martensia bibarii, Martensia elegans, Martensia flammifolia, Martensia fragilis, Martensia jejuensis, Martensia projecta, and Martensia palmata) occur on the Korean coast. Our recent Martensia collections from various localities in Korea contain many specimens with a huge range of morphological variation and are difficult to classify into the named species. In this study, we analyzed DNA sequences of rbcL and COI genes to access their phylogenetic relationships and to verify taxonomic status based on morphological observations. The molecular analyses revealed that only two species of Martensia occur in Korea (M. albida and M. jejuensis). Martensia albida is characterized by having entire margins of blades with a single band of networks, whereas M. jejuensis is distinguished from the other species by possessing projections along the margins of the networks and blades. Both molecular analyses and morphological observations revealed that M. flammifolia is a member of the genus Nitophyllum. Some features (e.g., thallus habit, branching patterns, blade morphology, positions of reproductive structures) are not reliable for species identification.Our results indicate that the rbcL and the COI gene have sufficient resolution for delimitation at both species and generic levels in the subfamily Nitophylloideae.

Characterization ofMartensia(Delesseriaceae; Rhodophyta) from shallow and mesophotic habitats in the Hawaiian Islands: description of four new species

“…1) are not closely allied with either material from Sri Lanka (the type locality for the species), or material known from any other location ( Fig. 1; Kang et al, 2015), and thus represent an undescribed species (most of the specimens are represented by the species described here as M. tsudae). The taxonomic situation for specimens previously referred to as M. flabelliformis (lineage 2, and some specimens in lineage 5, Fig.…”

“…Portions of the COI (cytochrome oxidase subunit I, 658 bp) barcoding region were amplified using the GazF2 and GazR2 primers (Saunders, 2005;Lane et al, 2007). Similarly, portions of the rbcL gene (ribulose 1,5-bisphosphate carboxylase/oxygenase large subunit; 1442 bp) were sequenced and assembled by amplifying two overlapping fragments using the primers rbcLF7 (Gavio & Fredericq, 2002) and rbcLJNR1 (Kang & Kim, 2013) for the first fragment, and rbcLF762 and rbcLR1442 (Kim et al, 2010) for the second fragment, as suggested by Kang et al (2015). For most Martensia DNA extracts, a 1:100 dilution was required for successful amplification and sequencing.…”

Taxonomic Revision of Hook-Forming Acrosorium (Delesseriaceae, Rhodophyta) from the Northwestern Pacific Based on Morphology and Molecular Data

“…Morphological plasticity, intraspecific variation in form due to environmental differences, makes identifying specimens difficult [33][34][35][36][37]. Similarly, different species with convergent morphologies are difficult to distinguish [38][39][40].…”

“…These dilemmas are not confined to any particular taxon or region, but to various macroalgae worldwide. Molecular methods using DNA sequencing have improved the delimitation of species with similar morphologies, as well as species with morphological plasticity in various taxonomic groups [33,37,[41][42][43]. In particular, chloroplast-encoded rbcL sequences are useful for species-level delimitation among members of the Delesseriaceae (e.g., [37,41,42,[44][45][46]), and a large quantity of verified rbcL sequences from previous studies is available from GenBank [47].…”

Phylogeography of the economic seaweeds <italic>Chondrus</italic> (Gigartinales, Rhodophyta) in the northwest Pacific based on <italic>rbc</italic>L and COI-5P genes

“…However, molecular techniques applied in other red algae have led to the discovery of multiple cryptic species that were previously classified as a single species (Yang and Kim 2018, Nauer et al 2019, Yang et al 2021a, Preuss et al 2022. Simultaneously, multiple species defined by morphological traits were found to belong to a singular species using molecular data (Kang et al 2015). Therefore, DNA-based phylo-…”