rbcL Sequence Analysis Research Articles

Fredericqia deveauniensis,gen. et sp. nov. (Phyllophoraceae, Rhodophyta), a New Cryptogenic Species

A species previously confused with Ahnfeltiopsis devoniensis in Ireland and with Gymnogongrus crenulatus in eastern Canada and north-eastern USA has remained undescribed because of its cryptogenic origin. Our published research suggested a trans-Atlantic introduction, possibly with ship ballast rock, but the relationship with A. leptophylla from California required further investigation and a North Pacific origin was possible. Here, we report that 34 samples of this species from Northern Ireland (UK), New Hampshire (USA) and New Brunswick (Canada) were genetically identical at the cox2–3 spacer locus, consistent with a recent introduction. By contrast, in A. leptophylla, four haplotypes were found in 9 samples from three sites in California. This species (as G. crenulatus) was recently discovered in the North Pacific for the first time, during surveys in British Columbia for the Canadian Barcode of Life Project. Phylogenetic analysis of plastid-encoded rbcL and mitochondrial cox1 gene sequences separate it from A. leptophylla in a robust clade with two North Pacific taxa, Gymnogongrus chiton (M.A. Howe) P.C. Silva et De Cew, and “Ahnfeltiopsis gigartinoides”, both from California. It is here described as a new species in a new genus, Fredericqia deveauniensis, gen. et sp. nov. The two other members of the genus are Fredericqia chiton (M.A. Howe) comb. nov. and Fredericqia decewii, sp. nov., previously known as Ahnfeltiopsis gigartinoides but not conspecific with the type from Mexico. Fredericqia species form extensive basal holdfasts giving rise to terete or compressed erect gametophytic axes 50–300 mm high. Procarps develop either into compact cystocarps with multiple ostioles but no mucilaginous sheath, or externally protruding carpotetrasporophytes (in F. chiton). Life histories are potentially heteromorphic (erect gametophytes and crustose sporophytes with compact, coalescent hypobasal tissue, forming catenate sporangia, both reproduce apomictically in F. deveauniensis), or carpotetrasporangial. F. deveauniensis differs from the other members of the genus in forming internal cystocarps on flattened blades.Ahnfeltiopsis / DNA barcoding / Gymnogongrus / introduction / molecular systematics

Variability of leaf morphology and marker genes of members of the halophila complex collected in Viet Nam

Seagrasses are marine angiosperms and adapted to aquatic life several times independently. In tropical as well as in temperate regions they play an important role in the coastal ecosystem. Classification according to morphology remains difficult due to very similar adaptations to the aquatic lifestyle and small simple flowers which are often not even formed. Especially the Halophila genus (Hydrocharitaceae) forms a complex group with an unresolved taxonomy due to overlapping morphological characters and high plasticity leading to many misidentifications. Hence, this led to the hypothesis that phylogenetic analysis on the molecular level may resolve taxonomic classification. The aim of this study is to identify and unambiguously characterize Halophila species collected in Viet Nam using tree- and character-based analysis of rbcL and matK sequences. Results obtained from molecular data and leaf morphology indicate that there are at least three species found in Viet Nam. Topologies based on single locus or combined datasets were similar but not equal. Analysis of rbcL sequences showed lowest species resolution when only Halophila beccarii Aschers was resolved at the Halophila complex. matK shows better resolution with respect to H. beccarii and H. decipiens Ostenfeld. Combined rbcL and matK consensus trees showed the highest species resolution when all species form three distinct clades representative for three difference species including H. beccarii, H. decipiens, and H. ovalis (R. Br.) Hook. f.

Molecular phylogeny of the genus Dichotomaria (Galaxauraceae, Rhodophyta) from the Indo-Pacific region, including a new species D. hommersandii from South Africa

Members of the Galaxauraceae are all calcified and have a wide distribution from tropical to temperate regions. Of the four genera of Galaxauraceae, only Dichotomaria contains two distinct thallus forms, which are (1) a flattened form with either narrow (e.g. D. marginata) or wide (e.g. D. diesingiana) branches, and (2) a terete form with either slender (e.g. D. papillata) or robust (e.g. D. obtusata) branches. In this study, we present a molecular phylogeny of new Dichotomaria samples from the Indo-Pacific region and describe a new species, D. hommersandii S.L. Liu & S.M. Lin, from South Africa, based on rbcL sequence analysis and morphological evidence. Dichotomaria hommersandii is characterized by a thallus consisting of terete smooth branches (0.5–1.5 mm in diameter), a moniliform branching pattern with constrictions at the nodes, ramification of young branches derived from the damaged terminal regions of the old branches, and cystocarps containing a conspicuous fusion cell. Our phylogenetic analyses indicate that the terete thallus morphology could be the ancestral character state in Dichotomaria.

Comparative morphology and systematics of Chondrymenia lobata from the Mediterranean Sea and a phylogeny of the Chondrymeniaceae fam. nov. (Rhodophyta) based on rbcL sequence analyses

The Chondrymeniaceae Rodríguez-Prieto, G. Sartoni, S.-M. Lin & Hommersand, fam. nov., is proposed for Chondrymenia lobata. Analyses of rbcL sequences place the new family in a large gigartinalean assemblage that comprises the Cystocloniaceae–Solieriaceae complex. Plants are decumbent and growth takes place by division of multiple apical cells at the margin of the blade. Thalli consist of an outer cortex of subspherical to elongate cortical cells arranged in anticlinal rows, a subcortex of cells cross-linked by lateral arms, and a large central medulla composed of primary medullary filaments intermixed with numerous rhizoidal filaments. Male stages are reported in monoecious individuals. Inactive carpogonial branches consist of a two-celled filament that is directed inwards from the supporting cell. Functional carpogonial branches are oriented outwardly, with the carpogonia and trichogynes pointed towards the thallus surface. After presumed fertilization, the carpogonium fuses with the hypogynous cell and transfers the zygote nucleus. The hypogynous cell, in turn, fuses with the supporting cell which contains many haploid nuclei. The resulting fusion cell functions as an auxiliary cell that cuts off a single gonimoblast initial, which produces the gonimoblast filaments. Gametophytic cells close to the auxiliary cell unite with it to form a placental fusion network of variable size and outline, and a placental fusion cell. Proximal gonimoblast cells fuse with the placental fusion cell, while the distal cells differentiate into branched chains of subspherical carposporangia. The superficial similarity of the outwardly developed osteolate cystocarp is responsible for Kylin's (1956) placement of Chondrymenia in his family Sarcodiaceae; however, the manner in which the placenta is formed is more like that seen in the Cystocloniaceae–Solieriaceae complex.

Transfer of the red alga Gelidium zollingeri Sonder (Gelidiales) to Yonagunia (Halymeniales) based on morphological and molecular evidence

Boo G.H, Park J.K., Gerung G.S. and Boo S.M. 2013. Transfer of the red alga Gelidium zollingeri Sonder (Gelidiales) to Yonagunia (Halymeniales) based on morphological and molecular evidence. Phycologia 52: 279–287. DOI: 10.2216/12–092.1An examination of the type specimen of Gelidium zollingeri Sonder showed that it was incorrectly placed in Gelidium. To determine the appropriate taxonomic position, we undertook a detailed morphological examination of the holotype (National Herbarium of Victoria, Australia) as well as fresh materials collected from Sempu, the type locality, and a surrounding location Kondang Merak in Malang city, East Jawa, Indonesia. In our collections we found tetrasporangia and carposporophytes on female thalli. The vegetative and reproductive structures clearly placed it in the Halymeniales. Four sequences of rbcL and cox1, two each from Sempu and Kondang Merak, were identical. Our analysis of rbcL sequences showed that G. zollingeri formed a monophyletic clade with the two known Yonagunia species, Y. formosana and Y. tenuifolia. Consequently, we proposed the new combination, Yonagunia zollingeri, based on Gelidium zollingeri. Yonagunia zollingeri was characterized by a cartilaginous, flattened thallus that was subcostate in lower parts, with cystocarpic leaflets that arose on terminal branchlets and round to heart-shaped tetrasporangial leaflets. Yonagunia is now known to occur in Indonesia, Japan (Okinawa), Malaysia, Taiwan, and Vietnam.

Characterization of Liagora ceranoides (Liagoraceae, Rhodophyta) on the basis of rbcL sequence analyses and carposporophyte development, including Yoshizakia indopacifica gen. et sp. nov. from the Indo-Pacific region

Lin S.-M., Huisman J.M. and Payri C. 2013. Characterization of Liagora ceranoides (Liagoraceae, Rhodophyta) on the basis of rbcL sequence analyses and carposporophyte development, including Yoshizakia indopacifica gen. et sp. nov. from the Indo-Pacific region. Phycologia 52: 161–170. DOI: 10.2216/12-101.1Liagora ceranoides, originally described from the Virgin Islands in the Caribbean Sea, has been widely reported from the Indo-Pacific but can easily be confused with other species/genera of the Liagoraceae in the field. In this study, we examined the vegetative and reproductive morphology of L. ceranoides-like specimens from Taiwan and New Caledonia in the western Pacific Ocean and from Western Australia in the eastern Indian Ocean, and we inferred their phylogenetic relationships along with related genera on the basis of rbcL sequence analyses. The molecular analyses demonstrated that the L. ceranoides-like specimens clustered into two distantly related clades that were characterized reproductively: clade I possessed unfused postfertilization carpogonial-branch cells and slightly diffuse gonimoblasts and clade II (including specimens from the type region of L. ceranoides) had fused postfertilization carpogonial-branch cells and compact gonimoblasts. We therefore proposed the new genus and species Yoshizakia indopacifica to include the specimens identified in clade I. Our phylogenetic analyses indicated that Liagoracean genera with relatively long involucral filaments and unfused carpogonial branches were closely related. Yoshizakia was readily separated from related genera by a combination of the behaviour of the carpogonial-branch cells and the development of involucral filaments and gonimoblasts following presumed fertilization. In addition, our rbcL sequence analyses have confirmed the previously suggested occurrence in the northeast Indian Ocean and the southwest Pacific Ocean of Titanophycus setchellii, Neoizziella asiatica and Macrocarpus perennis, all originally described from the northern or central Pacific Ocean.

Molecular identification of Grateloupia elliptica and G. lanceolata (Rhodophyta) inferred from plastid rbcL and mitochondrial COI genes sequence data

The marine red algae Grateloupia is the largest genus in the family Halymeniaceae and widely distributed from tropical to warm temperate regions of the world. In the genus Grateloupia, especially G. elliptica and G. lanceolata have common features of bladelike thalli with leather in texture and cruciately divided tetrasporangia. Due to this similar morphology, G. elliptica and G. lanceolata are frequently confused and resulted in considerable difficulty distinguishing these two taxa. We have reassessed the relationships between two species using molecular identification including plastid rbcL and mitochondrial COI genes to more accurately define their genetic diversity owing to the confusion of identification. As a result, the chloroplast-encoded rbcL sequence analyses support the distinction of two species, G. elliptica and G. lanceolata collected from Jeju Island, Korea and Japan at the species level, with interspecific divergence of 3.7-4.6 %. The genetic diversity of COI gene within species are estimated to be 0–0.3 % in G. elliptica and 0–1.0 % in G. lanceolata, respectively. The effectiveness of mtDNA COI barcoding in the identification for two species demonstrates in this study.

Pellaea flavescens, a Brazilian Endemic, is a Synonym of Old WorldPellaea viridis

A phylogenetic analysis of plastid rbcL sequences indicates that Pellaea flavescens from Brazil is nested within the Old World species Pellaea viridis. The morphology of these two species is similar and P. flavescens is here considered to be a synonym of the older P. viridis. This fern may have been introduced to and subsequently naturalized in Brazil or, alternatively, the natural result of long distance dispersal.

Morphology and molecular study of Pterosiphonia arenosa sp. nov. (Rhodomelaceae, Rhodophyta) from Jeju Island, Korea

The genus Pterosiphonia is composed of 22 species worldwide and four of these species have been reported in the North-East Asia. In Korea, P. pennata originally described from the Mediterranean Sea has been previously recorded from the southern coast as a widespread species. In order to confirm the same species from Korea and Mediterranean, we observed the morphology of Korean Pterosiphonia specimen and analyzed rbcL sequences for inferring phylogenetic relationships among similar congeners. Korean entity was recognized as a new species, Pterosiphonia arenosa sp. nov. The new species is characterized by ecorticate axes with 7-10 pericentral cells, branches formed every two segments, and coalesced with main axis over 1-1.25 axial segments, and tetrasporangia formed in straight series on determinate branches of the upper parts of erect axes. A phylogenetic analysis of rbcL sequences demonstrated that P. arenosa was distinct from P. pennata found in Spain as well as other species. In conclusion, morphological and molecular sequence data indicated that P. arenosa sp. nov. has been previously misidentified as P. pennata in Korea.

Molecular phylogeny and developmental studies of Apoglossum and Paraglossum (Delesseriaceae, Rhodophyta) with a description of Apoglosseae trib. nov.

Our morphological and molecular studies indicate that species from the southern hemisphere previously placed in Delesseria belong in Paraglossum and that Paraglossum and Apoglossum comprise a separate tribe, the Apoglosseae, S.-W. Lin, Fredericq & Hommersand, trib. nov., within the family Delesseriaceae. From a vegetative perspective the Apoglosseae is readily recognized because some or all fourth-order cell rows are formed on the inner sides of third-order cell rows. All fourth-order cell rows grow adaxially in Apoglossum, whereas both adaxial and abaxial cell rows are present in Paraglossum. Periaxial cells do not divide in Apoglossum, whereas they divide transversely in Paraglossum in the same way as in Delesseria. Major branches are formed mainly from the margins of midribs in the Apoglosseae. The procarp consists of a straight carpogonial branch and two sterile cells, with the second formed on the same side as the first. The carpogonium cuts off two connecting cells in tandem from its apical end, the terminal cell being nonfunctional and the subterminal cell typically fusing with the auxiliary cell. Gonimoblast filaments radiate in all directions from the gonimoblast initials and produce carposporangia terminally in branched chains, with pit connections between the inner gonimoblast cells broadening and enlarging. The auxiliary cell, supporting cell, and sterile cells unite into a fusion cell, which remains small in Apoglossum but incorporates the branched inner gonimoblast filaments and cells in the floor of the cystocarp in Paraglossum. Elongated inner cortical cells seen in mature cystocarps in the Delesserieae are absent in the Apoglosseae. Phylogenetic studies based on rbcL (RuBisCO large subunit gene) sequence analyses strongly support the recognition of the Apoglosseae within the subfamily Delesserioideae of the Delesseriaceae, in agreement with our previous observations based primarily on analyses of large subunit ribosomal DNA (LSU).

Taxonomic revision of the genus Lobophora (Dictyotales, Phaeophyceae) based on morphological evidence and analyses rbcL and cox3 gene sequences

Sun Z., Hanyuda T., Lim P.E., Tanaka J., Gurgel C.F.D. and Kawai H. 2012. Taxonomic revision of the genus Lobophora (Dictyotales, Phaeophyceae) based on morphological evidence and analyses rbcL and cox3 gene sequences. Phycologia 51: 500–512. DOI: 10.2216/11-85.1A taxonomic revision of Lobophora based on molecular phylogenetic analyses of rbcL and cox3 gene sequences as well as anatomical observations was carried out, mostly based on specimens collected from eastern Asia and southeastern Australia. In the molecular phylogenetic analyses, nine major clades supported by high bootstrap values were recognized. In combination with evaluation of morphological characters, four clades were concluded to be new species. The Australian species L. australis sp. nov. possessed erect thalli with sporangial sori scattered on the ventral surface and had a closer phylogenetic relationship with another Australian species, L. nigrescens, but it was distinguished from the latter in having fewer layers of cortical cells and smaller sporangia. The Asian species L. crassa sp. nov., L. pachyventera sp. nov. and L. asiatica sp. nov. possessed decumbent thalli with sporangia scattered on the dorsal surface. Among the three prostrate species, L. crassa had a considerably thicker thallus with four to five cortical layers, L. asiatica had a thinner thallus with two cortical layers, and L. pachyventera differed from another two species by its three-layered ventral cortex and well-developed anchoring rhizoids.

Two new species of Caloglossa (Delesseriaceae, Rhodophyta) from the Americas, C. confusa and C. fluviatilis spp. nov.

Krayesky D.M., Norris J.N., West J.A., Kamiya M., Viguerie M., Wysor B.S. and Fredericq S. 2012. Two new species of Caloglossa (Delesseriaceae, Rhodophyta) from the Americas, C. confusa sp. nov. and C. fluviatilis sp. nov. Phycologia 51: 513–530. DOI: 10.2216/11-57.1Although the systematics of Caloglossa has been intensely investigated, the species diversity of the genus is not yet fully understood. Comparative chloroplast-encoded rbcL and nuclear LSU rDNA sequence analyses, combined with morphological observations, reveal new records and two new species for the Americas. The species, previously identified as Caloglossa monosticha from the western Atlantic, is newly described as C. confusa sp. nov. It differs from Pacific Ocean C. monosticha primarily by its strongly constricted thallus nodes, and the sequence data presented here show that it is most closely allied with other taxa of the C. continua species complex, but its relationship with these taxa is not fully resolved. The freshwater C. fluviatilis sp. nov. from the Panama Canal is characterised by thalli arranged in tufts, adventitious branching, strong constrictions at the thallus nodes and lanceolate blades. Caloglossa fluviatilis forms a monophyletic group along with the species having only adventitious secondary branching. A dichotomous key highlights the diagnostic vegetative characters for separating the nine species of Caloglossa occurring in the Americas.

Osmotic stress in Arctic and Antarctic strains of the green alga Zygnema (Zygnematales, Streptophyta): Effects on photosynthesis and ultrastructure

The osmotic potential and effects of plasmolysis on photosynthetic oxygen evolution and chlorophyll fluorescence were studied in two Arctic Zygnema sp. (strain B, strain G) and two Antarctic Zygnema sp. (strain E, strain D). Antarctic strain D was newly characterized by rbcL sequence analysis in the present study. The two Antarctic strains, D and E, are most closely related and may represent different isolates of the same species, in contrast, strain B and G are separate lineages. Incipient plasmolysis in the cells was determined by light microscopy after incubating cells in sorbitol solutions ranging between 200mM and 1000mM sorbitol for 3, 6 and 24h. In Zygnema strain B and G incipient plasmolysis occurred at ∼600mM sorbitol solution (720mOsmolkg−1, ψ=−1.67MPa) and in strains D and E at ∼300mM (318mOsmolkg−1, ψ=−0.8MPa) sorbitol solution. Hechtian strands were visualized in all plasmolysed cells, which is particularly interesting, as these cells lack pores or plasmodesmata. Ultrastructural changes upon osmotic stress were a retraction of the condensed cytoplasm from the cell walls, damages to chloroplast and mitochondrial membranes, increasing numbers of plastoglobules in the chloroplasts and membrane enclosed particles in the extraplasmatic space. Maximum photosynthetic rates (Pmax) in light saturated range were between 145.5μmol O2 h−1mg−1Chl a in Zygnema G and 752.9μmol O2 h−1mg−1Chl a in Zygnema E. After incubation in 800mM sorbitol for 3h Pmax decreased to the following percentage of the initial values: B: 16.3%, D: 16.8%, E: 26.1% and G: 35.0%. Osmotic stress (800mM sorbitol) decreased maximum photochemical quantum yield of photosystem II (Fv/Fm) when compared to controls. Maximum values of relative electron transport rates of photosystem II (rETRmax) decreased after incubation in 400mM sorbitol in Zygnema D and E, while they decreased in Zygnema B and G only after incubation in 800mM sorbitol. The kinetics of the rETR curves were similar for the Arctic strains Zygnema B and G, but distinct from the Antarctic strains Zygnema D and E, which were similar when compared with each other. This suggests that the investigated Arctic Zygnema sp. strains might be better adapted to tolerate osmotic water stress than the investigated strains from the Antarctic.

Colpomenia durvillei (Scytosiphonaceae, Phaeophyceae): its distribution and relationships with other elongate species of the genus

Abstract The taxonomic distinctiveness and distribution of the brown alga Colpomenia durvillei are debatable; the species was first described from central Chile. We analyzed mitochondrial cox3 and plastid rbcL sequences from specimens collected in central Chile and Sonora, Mexico, in combination with morphological observations of specimens collected in Chile, Peru, and Mexico. Compared with other elongate species of the genus, C. durvillei is distinguished by erect, elongate thalli arising from a wide colpomenioid base, up to eight layers of cortical and medullary cells, and plurilocular sporangia with many layers (up to 18 locules). In all phylogenetic analyses of cox3 and rbcL sequences, all elongate species of the genus formed a clade, in which C. durvillei was consistently distinct from congeners. Colpomenia bullosa was closely related to C. durvillei in our cox3 analyses, and the clade containing these two species was closely related to Colpomenia phaeodactyla. This is the first report to confirm C. durvillei by molecular data and also the first report on the occurrence of the species in Sonora, Mexico. It had previously been misidentified as a variant of C. phaeodactyla on the Pacific coast of South America, and the name C. durvillei was misapplied to C. bullosa in New Zealand.

<p align="left"><strong>A new species of <em>Pyropia</em> (Rhodophyta, Bangiaceae), from the Pacific coast of Mexico, based on morphological and molecular evidence</strong></p>

Pyropia raulaguilarii sp. nov. is described from Michoacán, tropical Mexican Pacific, on basis of comparative morphology and nrSSU, rbcL sequence analysis. It is distinguished from other Pyropia species by the foliose and lanceolate gametophyte, a monoecious thallus and the zygotosporangia in packets of 2x2x4. The phylogenetic analysis showed that the two Pacific Mexican samples, from Caletilla and Carrizalillo (Michoacán), were almost identical and formed a distinctive and well supported clade segregated from other species of Pyropia from Brazil, USA and Mexico. The Mexican entity is morphologically and genetically distinct from other Pyropia species, suggesting that this species should be assigned to a new taxon.

Characterization and production of tetraspore-derived seedlings of Grateloupia lanceolata (Halymeniales, Rhodophyta) in northeastern China

Ye N., Zhang X., Wang H., Lian W., Mao Y., Xu D., Li B., Liang C., Zou J., Zhu B., Jiang Z., Gao Z. and Li D. 2012. Characterization and production of tetraspore-derived seedlings of Grateloupia lanceolata (Halymeniales, Rhodophyta) in northeastern China. Phycologia 51: 330–339. DOI: 10.2216/11-03.1In this study, Grateloupia lanceolata, newly recorded from northeastern China, was classified on the basis of morphology and rbcL sequence analysis and also raised in a laboratory to evaluate the feasibility of producing tetraspore-derived seedlings. Analysis of the rbcL sequence showed the samples to be monophyletic with G. lanceolata and different from any other species of the genus. Analysis of variance indicated that time has a significant (P < 0.01) effect on both tetraspore output and the percentage of total tetraspores released; those released in the first 2 d made up more than 72% of the total sporulation output; whereas, those released in the last 2 d contributed only 2.52%. In culture, tetraspores released from the unilocular sporangia developed into small discs in one week, and 87% ± 5.7% of the tetraspores that settled developed into sporelings after 9 wk of culture. Tetraspore culture of G. lanceolata in tanks and in the open sea proved to be a feasible method of generating large numbers of individual gametophytes economically.

Cryptonemia rotunda (Halymeniales) and Schizymenia apoda (Nemastomatales), two new records of red algae from Korea

Here we report the first finding of Cryptonemia rotunda and Schizymenia apoda in Korea based on plastid rbcL sequence analysis and morphological observations. C. rotunda occurred in the subtidal in Hongdo and Namyeodo on the south coast. Thalli have short stipe with foliose, membranous blades with dentate margin, a length of 2-8 cm. S. apoda occurred in many locations along the coast of Korea. Thalli are foliose, simple or broadly lanceolate blades with irregular lobes and proliferations from the margins, sometimes undulate, soft fleshy, and slippery, up to 32 cm tall, and have cystocarps with ostioles on the blade. Plastid rbcL sequences reveal that each of these species is clearly separated from other species of their respective genera. S. apoda was well resolved within the genus. However, C. rotunda was distantly related to other members of the genus, and this result needs an urgent revision of the genus.

A morphological and molecular assessment of the genus Sinotubimorpha (Halymeniaceae, Rhodophyta)

Abstract A critical reassessment of the morphological features of two closely related red algal genera, Grateloupia C. Agardh and Sinotubimorpha W. X. Li & Z. F. Ding (Halymeniaceae), pointed out that members of the two genera had most morphological characteristics in common, including the Grateloupia type auxiliary cell ampullae. Sinotubimorpha hitherto was distinguished from Grateloupia by: (i) the hollow axis; (ii) the presence of secondary filaments in ampullae; (iii) 1- to 3-celled carpogonial branch; and (iv) the occasional production of 1- to 4-celled flanking filaments on carpogonium. However, when these features were re-examined among 37 Chinese species of genera described in Flora Algarum Marinarum Sinicarum and one newly reported species, Grateloupia orientalis, we found that it was difficult to draw a clear-cut distinction between the two genera based only on morphological differences. In rbcL sequence analysis, all the species of Sinotubimorpha with G. catenata formed a single monophyletic subclade within the large Grateloupia clade of the Halymeniaceae. It is therefore suggested that all the Chinese species of Sinotubimorpha, S. catenata, S. guangdongensis, S. qingdaoensis, S. claviformis, and S. ramosissima should be synonymous with G. catenata, and that Sinotubimorpha should be included in synonymy under Grateloupia.

Ochtodes searlesii sp. nov. (Gigartinales, Rhodophyta), from the Pacific tropical coast of Mexico, based on morphological and molecular evidence

SUMMARYOchtodes searlesii Mendoza‐González, Mateo‐Cid et Sentíes sp. nov. is described from Michoacán, tropical Mexican Pacific, on the basis of comparative morphology and rbcL sequence analysis. It is distinguished from other Ochtodes species by its erect axes arising from an encrusting base, its small terete fronds, regularly dichotomously branched axes, and obliquely divided zonate tetrasporangia. Phylogenetic analyses showed that three Pacific Mexican samples, from Caletilla, Zapote and La Majahuita (Michoacán), were identical and formed a distinctive and well supported Clade segregated from other species of Ochtodes from Brazil, Cuba, Ecuador, Guadeloupe and Mexico. The Mexican entity is morphologically distinct from other Ochtodes species as well. On this basis we propose a new Ochtodes species.

Redefinition of Adiantopsis Fée (Pteridaceae): Systematics, diversification, and biogeography

AbstractWe present the first multi‐gene phylogeny of taxa potentially allied to the fern genus Adiantopsis, one of about 20 genera in the large group of cheilanthoid ferns. Our goals were to clarify natural relationships, examine generic boundaries, and interpret character evolution within a phylogenetic framework. Phylogenetic analysis of combined plastid rbcL and atpA DNA sequences has led to an expansion of generic boundaries in Adiantopsis, a recircumscription that is clearly defensible with morphological data. Biogeographic analyses suggest an origin for the genus in South America, with a minimum of three migrations into the Caribbean. We include a synopsis of the genus and two new combinations.