Search

Caulerpa J.V. Lamouroux is a genus of green macroalgae belonging to the family Caulerpaceae in the order Bryopsidales. The genus comprises 104 currently accepted species, of which 51 have been recorded from Pacific Islands. Among these islands, French Polynesia is found in the middle of the South Pacific Ocean and includes five archipelagos (i.e., the Austral, Gambier, Marquesas, Society, and Tuamotu Islands) where seaweed inventories have reported a total of 16 Caulerpa species so far based on morphology. Here, based on a sampling covering the five archipelagos of French Polynesia, we attempt to (i) verify the taxonomy of Caulerpa species present in these regions based on phylogeny, (ii) describe in more detail the specific diversity between the five archipelagos, and (iii) provide a morphological identification tool for these species. We successfully obtained 134 new tufA sequences for phylogenetic analyses, which corresponded to 13 species. We propose to resurrect C. pickeringii Harvey & Bailey for representatives of C. webbiana var. pickeringii and classify it in the Caulerpa subgenus Araucarioideae. We also transfer C. seuratii to C. pickeringii based on genetic results. A new morphological identification key is provided as well as an updated distribution of Caulerpa species across French Polynesia. [ABSTRACT FROM AUTHOR]

The marine brown algal genus Colpomenia has a worldwide distribution, with five species reported in Korea and Japan. However, no studies to date attempted to identify the number of species and geographical distribution of Colpomenia along Chinese coast. To fill the biodiversity knowledge gap, we analyzed 63 mitochondrial cox3 and 62 mitochondrial atp6 sequences of Colpomenia specimens collected from 30 localities along the Chinese coast. Maximum likelihood and Bayesian inference trees suggest the presence of at least three Colpomenia species (i.e., C. peregrina, C. claytoniae, and C. sinuosa) in China. C. peregrina and C. claytoniae are documented for the first time. C. sinuosa was only found in the South China Sea and its distribution didn't overlap with that of C. peregrina which was found in the Yellow-Bohai Sea and the East China Sea. C. claytoniae appears to be confined to three isolated islands in the East and the South China Sea, where it occurs in sympatry with, respectively, C. peregrina and C. sinuosa. Future study can focus on comparing ecophysiological differences of Colpomenia species in response to environmental variables and exploring possible genetic hybridization / introgression at inter-specific contact zones. [ABSTRACT FROM AUTHOR]

A phylogenetic analysis of DNA sequence data revealed that the morphological Caulerpa entities, previously reported as C. corynephora Montagne (or C. racemosa var. corynephora (Montagne) Weber-van Bosse) and C. ashmeadii Harvey from mangrove channels on the Thai Andaman Sea coast, are both representatives of C. macrodisca Decaisne. The analyzed Andaman Sea specimens formed one of four subclades in a monophyletic C. macrodisca clade that was sister to C. megadisca Belton & Gurgel. Ramuli arrangement of C. macrodisca from the Andaman Sea was mostly in opposite pairs and sometimes distichous. The shape of the ramuli varied from almost cylindrical to clavate or turbinate. No pyrenoid was observed. Caulerpa macrodisca with characteristic large peltate ramuli has only been reported in Thailand from the Gulf of Thailand. Its identity was confirmed with DNA sequence data from a herbarium specimen. It is recommended to refer to the three morphological C. macrodisca entities as ecads; i.e., C. macrodisca ecad macrodisca, ecad corynephora, and ecad ashmeadii. [ABSTRACT FROM AUTHOR]

1. In the planning of marine protected areas for the conservation of coral reef systems, it is important to be able to distinguish between certain bioregions, i.e. regions with distinct species assemblages. This was done off western Halmahera (Moluccas, Indonesia), where three such bioregions were distinguished based on species inventories of 41 coral reef sites. 2. The relative value of species belonging to different trophic groups was examined with regard to their possible role as indicators for these three regions. The study focused on ascidians (Ascidiacea), macroalgae, mushroom corals (Fungiidae), and a selection of coral-associated gastropods (Epitoniidae and Coralliophilidae). 3. The best results for the detection of bioregions were obtained when datasets of all four trophic groups were pooled. When comparing the taxa and their indicator values, ascidians were the most suitable, followed by macroalgae, corals and gastropods with 98, 83, 71 and 66 % certainties, respectively. The occurrence of 17 species correlated strongly with the bioregions, which therefore were identified as potential indicator species consisting of 13 ascidians, three macroalgae, and one mushroom coral. These data suggest that ascidians have a significant value as indicators to evaluate bioregion boundaries. 4. Water quality measurements indicated that salinity and turbidity could be responsible for at least part of the differences between the species assemblages in the three bioregions. [ABSTRACT FROM AUTHOR]

Although recent molecular studies have indicated the presence of a number of distinct species within the Caulerpa racemosa-peltata complex, due to the difficulties presented by high levels of phenotypic plasticity and the large number of synonyms, infra-specific taxa, and names of uncertain affinity, taxonomic proposals are yet to be made. In this study, we aimed to resolve the taxonomy of the complex and provide an example of how historical nomenclature can best be integrated into molecular based taxonomies. We accomplished this by first determining the number of genetic species within our globally sampled data set through a combination of phylogenetic and species-delimitation approaches of partial elongation factor TU and RUBISCO large subunit gene sequences. Guided by these results, comparative morphological examinations were then undertaken to gauge the extent of phenotypic plasticity within each species, as well as any morphological overlap between them. Our results revealed the presence of 11 distinct species within the complex, five of which showed high levels of phenotypic plasticity and partial overlap with other species. On the basis of observations of a large number of specimens, including type specimens/descriptions, and geographic inferences, we were able to confidently designate names for the lineages. Caulerpa peltata, C. imbricata and C. racemosa vars. laetevirens, occidentalis and turbinata were found to represent environmentally induced forms of a single species, for which the earlier-described C. chemnitzia, previously regarded as a synonym of C. racemosa var. turbinata, is reinstated. C. cylindracea, C. lamourouxii, C. macrodisca, C. nummularia and C. oligophylla are also reinstated and two new species, C. macra stat. nov. and C. megadisca sp. nov., are proposed. [ABSTRACT FROM AUTHOR]

Molecular characterization (plastid-encoded tufA gene) of New Caledonian members of the Caulerpa racemosa-Caulerpa peltata complex identified five lineages, each possibly harboring multiple species-level entities. On a global scale, the complex encompassed six lineages, two of which were pantropical and the remainder seemingly were restricted to the Indo-Pacific basin. Caulerpa racemosa var. cylindracea, a fast-spreading introduced taxon in the Mediterranean Sea and the Canary Islands, was previously thought to be restricted to southwestern Australia; it was newly reported here for New Caledonia and several northern Australian locations, including the Great Barrier Reef. [ABSTRACT FROM AUTHOR]

Two new species of Padina - 1. Padina sulcata sp. nov. and 2. P. calcarea sp. nov. - from Malaysia, Indonesia and Palau were described based on morphological and molecular phylogenetic observations. Padina sulcata was a three-layered species characterised by a covering of thick fibrous hairs from the base to the middle of the inferior surface (away from the in-rolled margin) of the thallus; conspicuous equally spaced hairlines that alternated between both frond surfaces; and broad, indusiate oogonial and tetrasporangial sori that occupied nearly the entire fertile zones, and the fertile zones were separated by sterile zones of equal width. Padina calcarea was a two-layered species characterised by a bright yellow inferior surface and a thick calcification on the superior surface (facing to the in-rolled margin), which imparted a strikingly whitish color; inconspicuous hairlines were confined to the inferior surface; and indusiate tetrasporangial sori were just above the hairlines and were found only on the inferior surface. Molecular phylogenetic analyses used chloroplast rbcL and mitochondrial cox3 gene sequences and revealed that the two new species each form strongly supported clades that were genetically distant. Padina calcarea formed an isolated clade that made an early divergence; whereas, P. sulcata showed a sister relationship to P. ryukyuana, indicating a more recent divergence. Padina calcarea was very similar to the Hawaiian P. melemele in gross appearance, particularly in the bright orange to yellow color of the inferior thallus surface and the heavy calcification on the superior surface. However, they were distinguished mainly by the position and arrangement of reproductive sori that were found on the inferior surface and located just above the hairlines in P. calcarea but that were found on the superior surface between the hairlines of the opposite surface in P. melemele. Molecular phylogenetic analyses did not reflect the morphological similarity of the two species because they occupied two distantly related clades. [ABSTRACT FROM AUTHOR]

A taxonomic study of the genus Padina from Japan, Southeast Asia, and Hawaii based on morphology and gene sequence data ( rbcL and cox3) resulted in the recognition of four new species, that is, Padina macrophylla and Padina ishigakiensis from Ryukyu Islands, Japan; Padina maroensis from Hawaii; and Padina usoehtunii from Myanmar and Thailand. All species are bistratose and morphologically different from one another as well as from any known taxa by a combination of characters relating to degree of calcification; the structure, position, and arrangement of hairlines (HLs) and reproductive sori; and the presence or absence of rhizoid-like groups of hairs and an indusium. Molecular phylogenetic analyses demonstrated a close relationship between P. ishigakiensis, P. macrophylla, P. maroensis, and Padina australis Hauck. The position of P. usoehtunii, however, was not fully resolved, being either sister to a clade comprising the other three new species and P. australis in the rbcL tree or more closely related to a clade comprising several other recently described species in the cox3 tree. The finding of the four new species demonstrates high species diversity particularly in southern Japan. The following characters were first recognized here to be useful for species delimitation: the presence or absence of small rhizoid-like groups of hairs on the thallus surface, structure and arrangement of HLs on both surfaces either alternate or irregular, and arrangement of the alternating HLs between both surfaces in equal or unequal distance. The evolutionary trajectory of these and six other morphological characters used in species delineation was traced on the phylogenetic tree. [ABSTRACT FROM AUTHOR]

Comparative rbcL sequence analysis indicates that the species going under the name Schizymenia dubyi in the Azores should be referred to as S. apoda. Sequences of Schizymenia specimens from China and Namibia were also identified as S. apoda, of which the type locality is the Cape Province in South Africa. Schizymenia dubyi, described from Atlantic France, is clearly a distinct species that we here report for Japan and Sicily in the Mediterranean Sea. Both Schizymenia species, along with an unreported species from Japan, are distinct from S. pacifica described from Washington, in the Pacific Coast of North America. Secondary pit connections were observed in gametophytes of S. apoda from the Azores, a previously unknown character for the Nemastomatales. Examination of type material of Nemastoma confusum indicates that this species, currently placed in the Nemastomataceae, should be transferred to the genus Platoma in the Schizymeniaceae. A morphological comparison between Platoma confusum (Kraft & John) comb. nov. with descriptions of P. cyclocolpum and P. chrysymenioides suggests that the three species are closely related. [ABSTRACT FROM AUTHOR]

Molecular phylogenetic analyses of Padina species collected from the western Pacific Ocean using rbcL and mitochondrial cox3 genes revealed the occurrence of four genetically distinctive clades of unknown Padina species: clade A (=Padina okinawaensis sp. nov.) from Ryukyu Islands (Japan), Hawaii, Indonesia and Thailand, clade B (=Padina undulata sp. nov.), clade C (=Padina terricolor sp. nov.) and clade D (=Padina fasciata sp. nov.) from Ryukyu Islands (Japan). Morphologically, these new taxa are all bistratose species, and different from any known species in the following morphological features: P. okinawaensis sp. nov., reniform or circular thallus of entire margin with inconspicuous hair lines on the superior surface of the thallus, and reproductive organs (oogonia and tetrasporangia) in small groups or discontinuous sori under thin flakes of calcium on the inferior surface; P. undulata sp. nov., circular or semicircular thallus with undulate margin, conspicuous hair lines on both surfaces of the thallus, oogonial and tetrasporangial sori in continuous or discontinuous lines covered with a persistent indusium, and cylindrical oogonia; P. terricolor sp. nov., grayish brown on the inferior surface of the thallus, and oogonial and tetrasporangial sori in continuous lines covered with a persistent indusium; P. fasciata sp. nov., broad white stripes on both surfaces of the thallus due to unique calcification, and oogonial and tetrasporangial sori in continuous lines, which are entirely embedded in a gelatinous layer, on the inferior surface of the thallus. In addition, the independence of Padina japonica from Padina sanctae-crucis is suggested on the basis of molecular and morphological evidence. [ABSTRACT FROM AUTHOR]