Mi Yeon Yang

Molecular evidence for verifying the distribution of Chondracanthus chamissoi and C. teedei (Gigartinaceae, Rhodophyta)

Abstract Chondracanthus teedei and C. chamissoi are regarded as cosmopolitan and endemic species, respectively. To verify the geographic distribution of these two species, we analyzed specimens of C. teedei from the Western Pacific and the Atlantic coast of Spain, as well as of C. chamissoi from Chile using plastid rbcL and mitochondrial COI genes. The phylogenetic tree of rbcL revealed that “C. teedei” from Asia and Chondracanthus sp. from France are conspecific with C. chamissoi from Chile, but distinct from the clade of C. teedei from the Atlantic. These results indicate that C. chamissoi is not exclusively distributed in the southeastern Pacific, but is also found in Korea/Japan and France, whereas C. teedei is found in the Atlantic and not in the western Pacific region. This study demonstrated that the range of C. chamissoi is wider than previously thought, raising interesting questions regarding the transportation vector and the absence of C. teedei from Korea and Japan. In addition, we confirmed that molecular analyses can be used to examine the geographic distribution of marine macroalgae.

DNA barcode assessment of Gracilaria salicornia (Gracilariaceae, Rhodophyta) from Southeast Asia

BackgroundDNA barcoding is becoming a widely applied tool for the quick and accurate identification of species. The evolution of the mitochondrial cytochrome c oxidase subunit I (COI) gene is sufficiently rapid to allow discrimination between closely related species and biogeographic subgroups within species. Gracilaria salicornia was originally described as being from Manila, the Philippines, and is distributed throughout Asia and the Indian Ocean. To more accurately define this species and its genetic diversity owing to the confusion of identification historically, DNA barcoding using the 5’ end of the COI gene of the mitochondrial genome was applied to specimens collected from the Philippines, Malaysia, Thailand, China, and Japan, and they were compared to other gracilarian species.ResultsWithin species, the COI marker yielded two clusters with nucleotide divergences of 0.0–1.3%. This divergence is slightly higher than the typical intraspecific variation for red algae. A total of eight COI haplotypes were found for G. salicornia, comprising the following groups: H1–H3 from the Philippines; H4 from Okinawa in Japan; H5–H7 from Malaysia, Thailand, and China; and H8 from Thailand.ConclusionAlthough this work concentrated on a limited geographical region of a widespread taxon, the data shows intraspecific molecular divergences in G. salicornia and provides further evidence that DNA barcodes are useful tools for identifying species boundaries and examining biogeographical haplotypes for the genus Gracilaria.

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.

Molecular phylogeny of the genus Chondracanthus (Rhodophyta), focusing on the resurrection of C. okamurae and the description of C. cincinnus sp. nov.

Determining the taxonomic status of the red algal genus Chondracanthus based on morphological characters is challenging due to the similarity and high degree of plasticity of the thallus. Since the taxonomic history of several Chondracanthus species remains unclear, we analyzed the plastid rbcL and mitochondrial COI genes of the specimens from Korea and Japan, in combination with morphological observations, to examine their phylogenetic relationships. Our results confirmed the distinction of C. okamurae, which is separated from C. intermedius, and identified a novel species, C. cincinnus sp. nov. Three species (C. okamurae, C. intermedius and C. cincinnus) formed a monophyletic clade with C. tenellus. C. okamurae is distinguished by linear, narrow, cylindrical to compressed, slightly recurved axes, and a high-intertidal to subtidal distribution. It was collected from Korea and Japan, while C. intermedius was identified from Japan only. A new species, Chondracanthus cincinnus sp. nov., is characterized by linear, compressed, strongly recurved axes, and a low-intertidal to subtidal distiribution. Based on the molecular phylogeny using rbcL and COI data, we herein resurrect C. okamurae as a distinct species and identify C. cincinnus as a new species.

DNA barcoding of the funoran-producing red algal genus Gloiopeltis (Gigartinales) and description of a new species, Gloiopeltis frutex sp. nov.

The funoran-producing red macroalga, Gloiopeltis, is known for its commercial uses. Since the economic value of Gloiopeltis is species-dependent, accurate species identification using molecular analysis such as DNA barcoding is important to obtain species-level identification and reveals the hitherto undiscovered biodiversity in Gloiopeltis. In this study, we investigated Gloiopeltis complanata specimens from various locations across Japan and Korea to confirm their relationships with specimens from the type locality in Japan. We employed a combination of molecular analyses using mitochondrial COI-5P as DNA barcoding and plastid rbcL markers, as well as detailed morphological examination of reproductive structures. Genetic analysis revealed the presence of two deeply divergent clades with nucleotide difference of 16.8–17.5% in COI-5P and 6.3–6.8% in rbcL, respectively. The difference in the position of reproductive structure in thallus further supported the subdivision of the Japanese and Korean specimens. As a result, we describe a new species, Gloiopeltis frutex sp. nov., based on the Korean specimens characterized by caespitose and subcylindrical to compressed thallus, slightly flexuous siphonous axis, cruciately divided tetrasporangia scattered over thallus, and slightly swollen cystocarps on proliferations. The results also suggest the necessity of further studies aimed at examining full spectrum of genetic diversity manifested in species of the family Endocladiaceae in detail.

New record of Hypnea flexicaulis in New Zealand and description of Calliblepharis psammophilus sp. nov.

Abstract The genus Hypnea has been known in New Zealand for a long time but identification to species level has been difficult as only fragmentary and sterile material has been available for study and thus the genus has remained poorly known. Recently large amounts of Hypnea were collected in northern New Zealand enabling DNA sequencing and the presence of two species was confirmed: Hypnea flexicaulis which represents a new record for New Zealand, and Hypnea cornuta which was previously known from fragmentary material. Both of these species are regarded as introduced in other regions of the world. The new species described in this paper as Calliblepharis psammophilus was identified in the field as a species of Hypnea but morphological observations and molecular data confirmed it does not belong to this genus. It is characterized by caespitose thalli with irregularly branched terete axes and with tapering or curved tips, the axial cell enclosed by 5–7 pericentral cells, cortical cells packed tightly and not forming “rosettes” in surface view. The gonimoblast filaments originate from a fusion cell and develop outwardly in chains. This species is currently known from a single location in the North Island (south eastern coast), New Zealand.

Neoharaldiophyllum, a new genus of Delesseriaceae (Rhodophyta) based on carposporophyte development and molecular data

Abstract The new genus Neoharaldiophyllum J.C. Kang et M.S. Kim belonging to the tribe Myriogrammeae, subfamily Phycodryoideae of the Delesseriaceae, is described. This new genus consists of four species, namely Neoharaldiophyllum udoense (M.S. Kim et J.C. Kang) gen. et comb. nov. from Jeju Island Korea as the type species, Neoharaldiophyllum nottii (R.E. Norris et M.J. Wynne) J.C. Kang et M.S. Kim comb. nov. from the Hood Canal, Mason County, Washington, USA, Neoharaldiophyllum mirabile (Kylin) J.C. Kang et M.S. Kim comb nov. from Canoe Island, San Juan County, Washington, USA, and Neoharaldiophyllum erosum (Harvey) J.C. Kang et M.S. Kim comb. nov. from Garden Island, Western Australia. The morphological traits of the new genus are very similar to the genera Haraldiophyllum and Myriogramme in terms of the vegetative and reproductive structures. There are differences among the three genera in the developmental patterns of the carposporophyte: the primary gonimoblast cells of Neoharaldiophyllum are prostrate on the floor cells of the cavity of the cystocarp and fuse together secondarily, whereas in the two other genera they remain free without a secondary incorporation with the floor cells; the carposporangia of Myriogramme are borne in short chains terminating the gonimoblast filaments, while those in the other two genera are borne as solitary structures. The molecular phylogenies based on rbcL and LSU sequences strongly support the significance of the developmental patterns of the carposporophyte and support the separation of Neoharaldiophyllum from Haraldiophyllum in the tribe Myriogrammeae.

Delimiting the species Neosiphonia yendoi (Rhodomelaceae, Rhodophyta) based on COI and rbcL genetic variation in Korea and Japan

AbstactAlthough the marine red algal genus Neosiphonia is well characterized, many species of Neosiphonia are poorly understood. To correctly define the species delimitation of Neosiphonia yendoi using genetic variation, owing to the confusion over identification with “N. sphaerocarpa” from Korea, we investigated intensively the haplotype network of the mitochondrial COI and the plastid rbcL genes of specimens collected from Korea and Japan. The molecular analyses indicated that specimens collected in different sites of Korea and Japan belong to the same species, Neosiphonia yendoi and “Neosiphonia sphaerocarpa” from Korea, which is distinguished from N. sphaerocarpa from Florida and is allied with N. yendoi collected from the type locality, Muroran of Japan. A total of 29 COI and 13 rbcL haplotypes were found and the COI haplotype network shows evidence of a clear break between specimens from Jeju Island and all other locations of Korea, suggesting the possibility of cryptic diversity within N. yendoi.