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Gary W. Saunders - One of the best experts on this subject based on the ideXlab platform.
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Multigene phylogeny of the red algal subclass Nemaliophycidae.
Molecular phylogenetics and evolution, 2015Co-Authors: Daryl W. Lam, Gary W. Saunders, Heroen Verbruggen, Morgan L. VisAbstract:The red algae (Rhodophyta) are a lineage of primary endosymbionts whose ancestors represent some of the first photosynthetic eukaryotes on the planet. They primarily inhabit marine ecosystems, with only ∼5% of species found in freshwater systems. The subclass Nemaliophycidae is very diverse in ecological and life history features and therefore a useful model to study these traits, but the phylogenetic relationships among the orders are, for the most part, poorly resolved. To elucidate the phylogeny of the Nemaliophycidae, we constructed a nine-gene dataset comprised of nuclear, plastid, and mitochondrial markers for 67 red algal specimens. The resulting maximum likelihood (ML) phylogeny confirmed the monophyly of all orders. The sister relationship of the Acrochaetiales and Palmariales received high support and the relationship of the Balliales with Balbianiales and Entwisleiales with Colaconematales was moderately supported. The Nemaliales, Entwisleiales, Colaconematales, Palmariales and Acrochaetiales formed a highly supported clade. Unfortunately, all other relationships among the orders had low bootstrap support. Although the ML analysis did not resolve many of the relationships, further analyses suggested that a resolution is possible. A Phycas analysis supported a dichotomously branching tree and Bayesian analysis showed a similar topology with all relationships highly supported. Simulations extrapolating the number of nucleotide characters beyond the current size of the dataset suggested that most nodes in the phylogeny would be resolved if more data become available. Phylogenomic approaches will be necessary to provide a well-supported phylogeny of this subclass with all relationships resolved such that the evolution of freshwater species from marine ancestors as well as reproductive traits can be explored.
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Establishment of a DNA-barcode library for the Nemaliales (Rhodophyta) from Canada and France uncovers overlooked diversity in the species Nemalion helminthoides (Velley) Batters
Cryptogamie Algologie, 2010Co-Authors: Line Le Gall, Gary W. SaundersAbstract:De nombreuses etudes ont montre l'utilite du code a barres ADN pour definir les frontieres des especes d'algues rouges et ont demontre en outre que notre comprehension de la diversite biologique et de la biogeographie des representants de ce groupe etait loin d'etre complete. Nous avons donc constitue des bibliotheques de sequences code-barres ADN des algues rouges canadiennes et francaises. Dans le present article, nous presentons des resultats concernant la diversite de representants des Nemaliales. Quatre-vingt-sept individus des cotes du Canada et de la France ont ete etudies, avec un echantillonnage incluant des specimens provenant de trois oceans (Pacifique, Arctique, Atlantique) et deux mers (la Manche et la Mediterranee). Nos sequences confirment bien la presence et la definition de chacune des 15 especes de Nemaliales que nous nous attendions a recolter dans ces regions, les sequences de leurs representants ayant entre elles des divergences genetiques ≤ 1%, a l'exception de Nemalion helminthoides (Velley) Batters dont il est apparu que les representants etudies constituent cinq lignees differentes, distantes genetiquement entre-elles de 10 a 18 %. Deux specimens de Bretagne et des Asturies ont ete rapportes a Nemalion helminthoides ; nous avons propose provisoirement de nommer nos recoltes du Pacifique Nemalion vermiculare Suringar mais une sequence d'un specimen de la localite type est necessaire pour avoir une certitude ; nous avons ressuscite le nom Nemalion lubricum Duby pour le specimen mediterraneen de ce genre et ressuscite le nom Nemalion multifidum (F. Weber et D. Mohr) Chauvin pour des specimens recoltes des deux cotes de l'ocean Atlantique nord et differant morphologiquement de N. helminthoides. Nous avons aussi decouvert le stade encroutant de Scinaia interrupta (A.P. de Candolle) M.J. Wynne dans les eaux pacifiques canadiennes, ce qui represente une extension significative de la zone de distribution actuellement connue de cette espece. Enfin, nos analyses Bayesiennes du gene nucleaire codant pour l'ARN ribosomique 28S (large subunit ribosomal DNA ou LSU) confirment que Whidbeyella cartilaginea Setchell et N.L. Gardner doit etre place dans les Scinaiaceae ; cette position systematique avait jusqu'ici ete proposee sans certitude, sur la base de l'existence, chez cette espece, de caracteristiques morpho/anatomiques particulieres.
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a nuclear phylogeny of the florideophyceae rhodophyta inferred from combined ef2 small subunit and large subunit ribosomal dna establishing the new red algal subclass corallinophycidae
Molecular Phylogenetics and Evolution, 2007Co-Authors: Line Le Gall, Gary W. SaundersAbstract:Previous studies have indicated that resolution of supraordinal relationships in the red algal class Florideophyceae will require additional characters, improved taxon sampling and optimized methods of phylogenetic analysis. To this end, we have generated data to introduce a novel nuclear marker to red algal systematics, elongation factor 2, as well as expanded ribosomal DNA alignments (SSU and LSU) to include 62 ingroup and 4 outgroup taxa. Both single gene and combined data sets were considered. Our analyses resulted in better resolution of both deep as well as more recent divergences, with higher support realized at many nodes. Distance, parsimony and bayesian analyses of the single gene and combined data sets indicated that the subclasses Hildenbrandiophycidae, Ahnfeltiophycidae and Rhodymeniophycidae were monophyletic, whereas the Nemaliophycidae was polyphyletic: one lineage containing the Rhodogorgonales and Corallinales (CR complex); and the other containing the Acrochaetiales, Balbianiales, Balliales, Batrachospermales, Colaconematales, Nemaliales, Palmariales, and Thoreales (APB complex). Based on these results a new subclass of the Florideophyceae, the Corallinophycidae subclassis nov., is proposed to accommodate the Corallinales and Rhodogorgonales. In addition to resolving supraordinal relationships, the present analyses resolved some novel ordinal affinities within the Nemaliophycidae and Rhodymeniophycidae, which are discussed here.
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Phylogenetic study of the Nemaliales (Rhodophyta) based on large‐subunit ribosomal DNA sequences supports segregation of the Scinaiaceae fam. nov. and resurrection of Dichotomaria Lamarck
Phycological Research, 2004Co-Authors: John M. Huisman, James T. Harper, Gary W. SaundersAbstract:Gene sequence data have been newly obtained for 18 species in 13 genera of the order Nemaliales (Rhodophyta), allowing for the first time a relatively comprehensive molecular phylogenetic appraisal of the order. The phylogenetic trees generated from these data support the recognition of three families: (i) the Liagoraceae as presently constituted; (ii) a reduced Galaxauraceae including Actinotrichia, Galaxaura (sensu lato), and Tricleocarpa; and (iii) a new family, Scinaiaceae, segregated from the Galaxauraceae and including the genera Scinaia, Gloiophloea, Nothogenia, and probably Whidbeyella. The four genera of the Scinaiaceae differ from the newly circumscribed Galaxauraceae in being uncalcified, and having heteromorphic life histories in which the tetrasporophyte is much reduced and filamentous or crustose. This type of life history is found in only Tricleocarpa of the Galaxauraceae. The results also show Galaxaura to be para/polyphyletic if Actinotrichia and Tricleocarpa are recognized. To remedy this, the Galaxaura marginata species complex, Galaxaura diesingiana, and Galaxaura obtusata are removed from the genus and placed in the resurrected Dichotomaria Lamarck. Galaxaura marginata, presently thought to be wide-ranging and morphologically variable, is shown to comprise several species. As a consequence, Galaxaura tenera Kjellman and Brachycladia australis Sonder are removed from the synonymy of G. marginata and restored as independent species in Dichotomaria for South African and Australian isolates, respectively. The Liagoraceae is shown to encompass genera previously placed in the segregate families Nemaliaceae and Dermonemataceae, and the value of the reproductive characters used to define those taxa is discussed.
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phylogenetic study of the Nemaliales rhodophyta based on large subunit ribosomal dna sequences supports segregation of the scinaiaceae fam nov and resurrection of dichotomaria lamarck
Phycological Research, 2004Co-Authors: John M. Huisman, James T. Harper, Gary W. SaundersAbstract:Gene sequence data have been newly obtained for 18 species in 13 genera of the order Nemaliales (Rhodophyta), allowing for the first time a relatively comprehensive molecular phylogenetic appraisal of the order. The phylogenetic trees generated from these data support the recognition of three families: (i) the Liagoraceae as presently constituted; (ii) a reduced Galaxauraceae including Actinotrichia, Galaxaura (sensu lato), and Tricleocarpa; and (iii) a new family, Scinaiaceae, segregated from the Galaxauraceae and including the genera Scinaia, Gloiophloea, Nothogenia, and probably Whidbeyella. The four genera of the Scinaiaceae differ from the newly circumscribed Galaxauraceae in being uncalcified, and having heteromorphic life histories in which the tetrasporophyte is much reduced and filamentous or crustose. This type of life history is found in only Tricleocarpa of the Galaxauraceae. The results also show Galaxaura to be para/polyphyletic if Actinotrichia and Tricleocarpa are recognized. To remedy this, the Galaxaura marginata species complex, Galaxaura diesingiana, and Galaxaura obtusata are removed from the genus and placed in the resurrected Dichotomaria Lamarck. Galaxaura marginata, presently thought to be wide-ranging and morphologically variable, is shown to comprise several species. As a consequence, Galaxaura tenera Kjellman and Brachycladia australis Sonder are removed from the synonymy of G. marginata and restored as independent species in Dichotomaria for South African and Australian isolates, respectively. The Liagoraceae is shown to encompass genera previously placed in the segregate families Nemaliaceae and Dermonemataceae, and the value of the reproductive characters used to define those taxa is discussed.
John M. Huisman - One of the best experts on this subject based on the ideXlab platform.
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A phylogenetic re-appraisal of the family liagoraceae sensu lato (Nemaliales, rhodophyta) based on sequence analyses of two plastid genes and postfertilization development
Journal of phycology, 2015Co-Authors: Showe-mei Lin, John M. Huisman, Michael D. Guiry, Conxi Rodríguez-prieto, Claude Payri, Wendy A. Nelson, Shao-lun LiuAbstract:The marine red algal family Liagoraceae sensu lato is shown to be polyphyletic based on analyses of a combined rbcL and psaA data set and the pattern of carposporophyte development. Fifteen of eighteen genera analyzed formed a monophyletic lineage that included the genus Liagora. Nemalion did not cluster with Liagoraceae sensu stricto, and Nemaliaceae is reinstated, characterized morphologically by the formation of the primary gonimolobes by longitudinal divisions of the gonimoblast initial. Yamadaella and Liagoropsis, previously placed in the Dermonemataceae, are shown to be independent lineages and are recognized as two new families Yamadaellaceae and Liagoropsidaceae. Yamadaellaceae is characterized by two gonimoblast initials cut off bilaterally from the fertilized carpogonium and diffusely spreading gonimoblast filaments. Liagoropsidaceae is characterized by at least three gonimoblast initials cut off by longitudinal septa from the fertilized carpogonium. In contrast, Liagoraceae sensu stricto is characterized by a single gonimoblast initial cut off transversely or diagonally from the fertilized carpogonium. Reproductive features, such as diffuse gonimoblasts and unfused carpogonial branches following postfertilization, appear to have evolved on more than one occasion in the Nemaliales and are therefore not taxonomically diagnostic at the family level, although they may be useful in recognizing genera.
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Molecular diversity of the calcified red algal genus Tricleocarpa (Galaxauraceae, Nemaliales) with the description of T. jejuensis and T. natalensis
Phycologia, 2013Co-Authors: Jutarat Wiriyadamrikul, John M. Huisman, Paul John L. Geraldino, Khanjanapaj Lewmanomont, Sung Min BooAbstract:Tricleocarpa (Nemaliales) is a calcified, dichotomously branched red algal genus currently with two recognized species, T. cylindrica and T. fragilis, both widely distributed in warm temperate and tropical seas. We evaluated the relationships of Tricleocarpa using molecular markers, including 35 rbcL and 32 cox1 sequences, from specimens in the western Pacific, the Hawaiian Islands and South Africa. Our results demonstrated the presence of seven genetically distinct groups. The range of T. cylindrica was confirmed to include the West Indies, the Hawaiian Islands, and Asian waters, and specimens referable to T. fragilis were found in Asia. On the basis of our molecular analyses and detailed morphological examinations, we were able to discriminate two taxa that we here describe as new species: T. jejuensis sp. nov. and T. natalensis sp. nov. Tricleocarpa jejuensis, known from Korea, Japan, South Africa, and Taiwan, was distinguished by the presence of three to four cortical cell layers with elongated to compressed subsurface and innermost cells, monoecious sexuality, spherical cystocarps, and paraphyses intermixed with gonimoblast filaments. Tricleocarpa natalensis from Kwazulu-Natal, South Africa was characterized by three layers of elongate cortical cells, monoecious sexuality, hemispherical cystocarps, and paraphyses rarely intermixed with gonimoblast filaments. Our phylogenetic analyses indicated that three further clades were recognized at species level, but these were based on a few specimens and were not morphologically distinct; further sampling is needed in regions outside Asian waters before additional taxonomic revisions can be proposed.
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Algae of Australia: Nemaliales
2006Co-Authors: John M. HuismanAbstract:Description The marine algae are plants of considerable biological and economic importance. The Nemaliales, one of the most diverse and significant orders of red algae in Australian waters, is found on shores, in rockpools and in the subtidal on all coasts of Australia. These beautiful and unusual plants offer a spectacular range of form and colour; some are relatively firm and chalky, others are worm-like or are highly mucilaginous and have the consistency of jelly. This volume documents the 3 families, 20 genera and 55 species of Australian Nemaliales, and it is richly illustrated with colour photographs and line drawings. A detailed introduction to the history, structure, reproduction and relationships of the order is followed by advice on the microscopical examination of specimens, identification keys to families, genera and species and comprehensive descriptions of each taxon. Appendices include the description of the new genus Titanophycus and DNA sequence analyses of the evolutionary relationships of the order.
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Studies in the Liagoraceae (Nemaliales, Rhodophyta) I. The genus Trichogloea
Phycological Research, 2005Co-Authors: Isabella A. Abbott, John M. HuismanAbstract:The calcified, though strongly mucosoid gametophytes of Trichogloea (Nemaliales, Liagoraceae) usually appear seasonally for a short period in tropical and subtropical regions. Vegetative and reproductive characteristics of the presently recognized species, Trichogloea requienii (Mont.) Kutzing (the generitype), Trichogloea lubrica J. Agardh, and Trichogloea herveyi W. R. Taylor, are described and compared. In addition, the identities of two previously synonymized species, Trichogloea jadinii Borgesen and Trichogloea javensis B0rgesen are clarified. Species of the genus display considerable variation in habit and branching patterns, necessitating an assessment of reproductive structures for accurate identification. Reliable features of Trichogloea include the structure of the medulla and the cortical (assimilatory) filaments, location and structure of carpogonial branches and spermatangia, and the nature of sterile filaments in the vicinity of the cystocarp. Secondary features include both external and internal branching pattern, and the proportion of calcium carbonate to lubricous material, the latter having to be assessed from fresh collections. The present study provides a comparative morphological account of the species of Trichogloea. As a result, T. requienii, T. lubrica, T. herveyi are confirmed as independent species; T. jadinii is removed from synonymy with T. lubrica and placed in that of T. requienii, and T. javensis is confirmed as a synonym of Izziella orientalis (J. Agardh) Huisman et Schils.
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Phylogenetic study of the Nemaliales (Rhodophyta) based on large‐subunit ribosomal DNA sequences supports segregation of the Scinaiaceae fam. nov. and resurrection of Dichotomaria Lamarck
Phycological Research, 2004Co-Authors: John M. Huisman, James T. Harper, Gary W. SaundersAbstract:Gene sequence data have been newly obtained for 18 species in 13 genera of the order Nemaliales (Rhodophyta), allowing for the first time a relatively comprehensive molecular phylogenetic appraisal of the order. The phylogenetic trees generated from these data support the recognition of three families: (i) the Liagoraceae as presently constituted; (ii) a reduced Galaxauraceae including Actinotrichia, Galaxaura (sensu lato), and Tricleocarpa; and (iii) a new family, Scinaiaceae, segregated from the Galaxauraceae and including the genera Scinaia, Gloiophloea, Nothogenia, and probably Whidbeyella. The four genera of the Scinaiaceae differ from the newly circumscribed Galaxauraceae in being uncalcified, and having heteromorphic life histories in which the tetrasporophyte is much reduced and filamentous or crustose. This type of life history is found in only Tricleocarpa of the Galaxauraceae. The results also show Galaxaura to be para/polyphyletic if Actinotrichia and Tricleocarpa are recognized. To remedy this, the Galaxaura marginata species complex, Galaxaura diesingiana, and Galaxaura obtusata are removed from the genus and placed in the resurrected Dichotomaria Lamarck. Galaxaura marginata, presently thought to be wide-ranging and morphologically variable, is shown to comprise several species. As a consequence, Galaxaura tenera Kjellman and Brachycladia australis Sonder are removed from the synonymy of G. marginata and restored as independent species in Dichotomaria for South African and Australian isolates, respectively. The Liagoraceae is shown to encompass genera previously placed in the segregate families Nemaliaceae and Dermonemataceae, and the value of the reproductive characters used to define those taxa is discussed.
James T. Harper - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic study of the Nemaliales (Rhodophyta) based on large‐subunit ribosomal DNA sequences supports segregation of the Scinaiaceae fam. nov. and resurrection of Dichotomaria Lamarck
Phycological Research, 2004Co-Authors: John M. Huisman, James T. Harper, Gary W. SaundersAbstract:Gene sequence data have been newly obtained for 18 species in 13 genera of the order Nemaliales (Rhodophyta), allowing for the first time a relatively comprehensive molecular phylogenetic appraisal of the order. The phylogenetic trees generated from these data support the recognition of three families: (i) the Liagoraceae as presently constituted; (ii) a reduced Galaxauraceae including Actinotrichia, Galaxaura (sensu lato), and Tricleocarpa; and (iii) a new family, Scinaiaceae, segregated from the Galaxauraceae and including the genera Scinaia, Gloiophloea, Nothogenia, and probably Whidbeyella. The four genera of the Scinaiaceae differ from the newly circumscribed Galaxauraceae in being uncalcified, and having heteromorphic life histories in which the tetrasporophyte is much reduced and filamentous or crustose. This type of life history is found in only Tricleocarpa of the Galaxauraceae. The results also show Galaxaura to be para/polyphyletic if Actinotrichia and Tricleocarpa are recognized. To remedy this, the Galaxaura marginata species complex, Galaxaura diesingiana, and Galaxaura obtusata are removed from the genus and placed in the resurrected Dichotomaria Lamarck. Galaxaura marginata, presently thought to be wide-ranging and morphologically variable, is shown to comprise several species. As a consequence, Galaxaura tenera Kjellman and Brachycladia australis Sonder are removed from the synonymy of G. marginata and restored as independent species in Dichotomaria for South African and Australian isolates, respectively. The Liagoraceae is shown to encompass genera previously placed in the segregate families Nemaliaceae and Dermonemataceae, and the value of the reproductive characters used to define those taxa is discussed.
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phylogenetic study of the Nemaliales rhodophyta based on large subunit ribosomal dna sequences supports segregation of the scinaiaceae fam nov and resurrection of dichotomaria lamarck
Phycological Research, 2004Co-Authors: John M. Huisman, James T. Harper, Gary W. SaundersAbstract:Gene sequence data have been newly obtained for 18 species in 13 genera of the order Nemaliales (Rhodophyta), allowing for the first time a relatively comprehensive molecular phylogenetic appraisal of the order. The phylogenetic trees generated from these data support the recognition of three families: (i) the Liagoraceae as presently constituted; (ii) a reduced Galaxauraceae including Actinotrichia, Galaxaura (sensu lato), and Tricleocarpa; and (iii) a new family, Scinaiaceae, segregated from the Galaxauraceae and including the genera Scinaia, Gloiophloea, Nothogenia, and probably Whidbeyella. The four genera of the Scinaiaceae differ from the newly circumscribed Galaxauraceae in being uncalcified, and having heteromorphic life histories in which the tetrasporophyte is much reduced and filamentous or crustose. This type of life history is found in only Tricleocarpa of the Galaxauraceae. The results also show Galaxaura to be para/polyphyletic if Actinotrichia and Tricleocarpa are recognized. To remedy this, the Galaxaura marginata species complex, Galaxaura diesingiana, and Galaxaura obtusata are removed from the genus and placed in the resurrected Dichotomaria Lamarck. Galaxaura marginata, presently thought to be wide-ranging and morphologically variable, is shown to comprise several species. As a consequence, Galaxaura tenera Kjellman and Brachycladia australis Sonder are removed from the synonymy of G. marginata and restored as independent species in Dichotomaria for South African and Australian isolates, respectively. The Liagoraceae is shown to encompass genera previously placed in the segregate families Nemaliaceae and Dermonemataceae, and the value of the reproductive characters used to define those taxa is discussed.
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A re-classification of the Acrochaetiales based on molecular and morphological data, and establishment of the Colaconematales ord. nov. (Florideophyceae, Rhodophyta)
European Journal of Phycology, 2002Co-Authors: James T. Harper, Gary W. SaundersAbstract:Systematics of the red algal order Acrochaetiales and related taxa was investigated using combined small- and large-subunit nuclear ribosomal DNA (SSU and LSU rDNA, respectively) sequence data. These data were subjected to distance, parsimony and maximum likelihood analyses. The resulting phylogenies were congruent with previously published SSU results in that all included orders (Balbianiales, Batrachospermales, Nemaliales, Palmariales and Thoreales) were resolved as monophyletic except the Acrochaetiales, which consisted of two lineages (Acrochaetiales I and II). The Batrachospermales and Thoreales occupied equivocal positions as early diverging lineages, while the Balbianiales generally resolved as sister to an Acrochaetiales–Nemaliales–Palmariales (ANP) complex. Relationships among the four lineages of the ANP complex were not completely resolved, but detailed analyses weakly positioned Acrochaetiales II as sister to the Nemaliales, whereas Acrochaetiales I displayed a moderate to strong affiliation w...
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MOLECULAR SYSTEMATICS OF THE FLORIDEOPHYCEAE (RHODOPHYTA) USING NUCLEAR LARGE AND SMALL SUBUNIT rDNA SEQUENCE DATA
Journal of Phycology, 2001Co-Authors: James T. HarperAbstract:Sequence data are presented for approximately 85% of the nuclear large subunit (LSU) rDNA gene for one member of the Bangiophyceae and 47 members of the Florideophyceae, the latter representing all but one of the currently recognized florideophyte orders. Distance, parsimony, and maximum likelihood analyses of these data were used to generate phylogenetic trees, and bootstrap resampling was implemented to infer robustness for distance and parsimony results. LSU phylogenies were congruent with published nuclear small subunit (SSU) rDNA results in that four higher level florideophyte lineages were resolved: lineage 1, containing the order Hildenbrandiales; lineage 2, recovered only under distance analysis, composed of the orders Acrochaetiales, Balliales, Batrachospermales, Corallinales, Nemaliales, Palmariales, and Rhodogorgonales; lineage 3, containing the Ahnfeltiales; and lineage 4, composed of the orders Bonnemaisoniales, Ceramiales, Gelidiales, Gigartinales, Gracilariales, Halymeniales, Plocamiales, and Rhodymeniales. Analyses were also performed on a combined LSU-SSU data set and an SSU-only data set to account for differences in taxon sampling relative to published studies using this latter gene. Combined LSU-SSU analyses resulted in phylogenetic trees of similar topology and support to those obtained from LSU-only analyses. Phylogenetic trees produced from SSU-only analyses differed somewhat in particulars of branching within lineages 2 and 4 but overall were congruent with the LSU-only and combined LSU-SSU results. We close with a discussion of the phylogenetic potential that the LSU has displayed thus far for resolving relationships within the Florideophyceae.
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A REEXAMINATION OF THE SYSTEMATICS OF THE ACROCHAETIALES (RHODOPHYTA) USING LARGE‐SUBUNIT RDNA SEQUENCE DATA
Journal of Phycology, 2000Co-Authors: James T. Harper, Gary W. SaundersAbstract:The taxonomic history of the red algal order Acrochaetiales is chaotic. There is no consensus in the literature as to how many genera should be recognized or in the assignment of the over 400 species to these genera. Morphological and anatomical studies have provided a suite of possible characters to delineate genera within this order, but there have been major discrepancies in the assessment and use of these features. The phylogenetic placement of the Acrochaetiales has also been the focus of debate. Once thought to be the most ancestral florideophyte lineage, recent molecular systematic studies have illustrated that this order is a derived lineage closely related to the Nemaliales and Palmariales. Phylogenies using sequences of the small-subunit (SSU) rDNA have strongly supported two very divergent lineages within a possibly polyphyletic Acrochaetiales. The relationships between these two groups and among other closely related rhodophyte orders were not resolved. We have generated large-subunit (LSU) rDNA sequence data for representatives of the Acrochaetiales and related taxa. Distance and parsimony phylogenies based on LSU and combined SSU and LSU data will be presented. The increased phylogenetic signal afforded by this approach will shed light on previous conundrums in the systematics of this group.
Isabella A. Abbott - One of the best experts on this subject based on the ideXlab platform.
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Studies in the Liagoraceae (Nemaliales, Rhodophyta) I. The genus Trichogloea
Phycological Research, 2005Co-Authors: Isabella A. Abbott, John M. HuismanAbstract:The calcified, though strongly mucosoid gametophytes of Trichogloea (Nemaliales, Liagoraceae) usually appear seasonally for a short period in tropical and subtropical regions. Vegetative and reproductive characteristics of the presently recognized species, Trichogloea requienii (Mont.) Kutzing (the generitype), Trichogloea lubrica J. Agardh, and Trichogloea herveyi W. R. Taylor, are described and compared. In addition, the identities of two previously synonymized species, Trichogloea jadinii Borgesen and Trichogloea javensis B0rgesen are clarified. Species of the genus display considerable variation in habit and branching patterns, necessitating an assessment of reproductive structures for accurate identification. Reliable features of Trichogloea include the structure of the medulla and the cortical (assimilatory) filaments, location and structure of carpogonial branches and spermatangia, and the nature of sterile filaments in the vicinity of the cystocarp. Secondary features include both external and internal branching pattern, and the proportion of calcium carbonate to lubricous material, the latter having to be assessed from fresh collections. The present study provides a comparative morphological account of the species of Trichogloea. As a result, T. requienii, T. lubrica, T. herveyi are confirmed as independent species; T. jadinii is removed from synonymy with T. lubrica and placed in that of T. requienii, and T. javensis is confirmed as a synonym of Izziella orientalis (J. Agardh) Huisman et Schils.
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VEGETATIVE AND REPRODUCTIVE MORPHOLOGY IN RETICULOCAULIS GEN. NOV. AND NACCARIA HAWAIIANA SP. NOV. (RHODOPHYTA, NACCARIACEAE)1
Journal of Phycology, 2004Co-Authors: Isabella A. AbbottAbstract:A secondarily formed reticulum of cells that encloses axial strands and a carposporophyte that is almost entirely converted to sporangia are the diagnostic features of a new genus, Reticulocaulis (Naccariaceae, Nemaliales), with R. mucosissimus as the type species. A new species of Naccaria, N. hawaiiana permits close comparison with the new genus and other previously described species of Naccaria. Until now, no Naccariaceae were known in the Pacific, and these new taxa are part of the sketchily known subtidal marine flora of Hawaii.
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Large subunit rDNA gene sequences and reproductive morphology reveal Stenopeltis to be a member of the Liagoraceae (Nemaliales, Rhodophyta), with a description of Akalaphycus gen. nov
European Journal of Phycology, 2004Co-Authors: John M. Huisman, Isabella A. Abbott, Alison R. SherwoodAbstract:A morphological and gene sequence study has shown the red algal genus Stenopeltis to be a member of the Liagoraceae (Nemaliales), not the Polyidaceae (Gigartinales) where it was placed after being segregated from Rhodopeltis. Post-fertilization events in Stenopeltis gracilis (the type of the genus) include a spreading, diffuse gonimoblast arising directly from the zygote ( = post-fertilization carpogonium), and no auxiliary cells, features characteristic of the Liagoraceae. Moreover, phylogenetic analyses based on LSU (large subunit) rDNA sequences clearly place Stenopeltis in a clade with members of the Liagoraceae. These observations are at odds with the existing taxonomic placement of the genus and a re-interpretation of earlier observations purporting to show the presence of auxiliary cells is presented. The morphology and reproduction of the three species currently attributed to the genus, S. gracilis (the type), S. setchelliae, and S. liagoroides, are described. LSU sequences as well as carpogonial ...
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Large subunit rDNA gene sequences and reproductive morphology revealStenopeltisto be a member of the Liagoraceae (Nemaliales, Rhodophyta), with a description of Akalaphycusgen. nov.
2004Co-Authors: John M. Huisman, Isabella A. Abbott, Alison R. SherwoodAbstract:A morphological and gene sequence study has shown the red algal genus Stenopeltis to be a member of the Liagoraceae (Nemaliales), not the Polyidaceae (Gigartinales) where it was placed after being segregated from Rhodopeltis. Post-fertilization events in Stenopeltis gracilis (the type of the genus) include a spreading, diffuse gonimoblast arising directly from the zygote (= post-fertilization carpogonium), and no auxiliary cells, features characteristic of the Liagoraceae. Moreover, phylogenetic analyses based on LSU (large subunit) rDNA sequences clearly place Stenopeltis in a clade with members of the Liagoraceae. These observations are at odds with the existing taxonomic placement of the genus and a re-interpretation of earlier observations purporting to show the presence of auxiliary cells is presented. The morphology and reproduction of the three species currently attributed to the genus, S. gracilis (the type), S. setchelliae, and S. liagoroides, are described. LSU sequences as well as carpogonial branch and cystocarp morphology of S. setchelliae are distinct from those of S. gracilis (the type), and the segregate genus Akalaphycus is proposed to accommodate S. setchelliae and S. liagoroides.
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Morphology, reproduction, and the 18S rRNA gene sequence of Pihiella liagoraciphila gen. et sp. nov. (Rhodophyta), the so-called 'monosporangial discs' associated with members of the Liagoraceae (Rhodophyta), and proposal of the Pihiellales ord. nov.
Journal of Phycology, 2003Co-Authors: John M. Huisman, Alison R. Sherwood, Isabella A. AbbottAbstract:Pihiella liagoraciphila gen. et sp. nov. (Rhodophyta) is described for a minute endo/epiphyte that is commonly associated with members of the Liagoraceae (Nemaliales, Rhodophyta). Algae are discoid or subspherical and grow to a maximum diameter of 400 μm. Attachment is via isolated elongate rhizoids that penetrate into the loosely filamentous structure of the host or by a pad of several coalesced rhizoids where the host has a more cohesive cortex. Elongate surface hairs are common. Gametophytes are dioecious, the spermatangia arising on surface cells, and carpogonia with elongate trichogynes borne directly on undifferentiated surface supporting cells. Large sporangia form on stalk cells across the upper surface of the plants, these appearing to be either monosporangial or the result of fertilization of the carpogonia and equivalent to undivided zygotosporangia. Carposporophytes and tetrasporangia are unknown. 18S rRNA gene sequence analyses indicate that Pihiella constitutes a clade of long branch length most closely related to the Ahnfeltiales. The unique morphology and reproduction of Pihiella, combined with a substantial genetic divergence from the Ahnfeltiales, suggest that it is sufficiently distinct to warrant placement in a new family and order. We therefore describe the family Pihiellaceae and the order Pihiellales to accommodate the new genus.
Alison R. Sherwood - One of the best experts on this subject based on the ideXlab platform.
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Large subunit rDNA gene sequences and reproductive morphology reveal Stenopeltis to be a member of the Liagoraceae (Nemaliales, Rhodophyta), with a description of Akalaphycus gen. nov
European Journal of Phycology, 2004Co-Authors: John M. Huisman, Isabella A. Abbott, Alison R. SherwoodAbstract:A morphological and gene sequence study has shown the red algal genus Stenopeltis to be a member of the Liagoraceae (Nemaliales), not the Polyidaceae (Gigartinales) where it was placed after being segregated from Rhodopeltis. Post-fertilization events in Stenopeltis gracilis (the type of the genus) include a spreading, diffuse gonimoblast arising directly from the zygote ( = post-fertilization carpogonium), and no auxiliary cells, features characteristic of the Liagoraceae. Moreover, phylogenetic analyses based on LSU (large subunit) rDNA sequences clearly place Stenopeltis in a clade with members of the Liagoraceae. These observations are at odds with the existing taxonomic placement of the genus and a re-interpretation of earlier observations purporting to show the presence of auxiliary cells is presented. The morphology and reproduction of the three species currently attributed to the genus, S. gracilis (the type), S. setchelliae, and S. liagoroides, are described. LSU sequences as well as carpogonial ...
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Large subunit rDNA gene sequences and reproductive morphology revealStenopeltisto be a member of the Liagoraceae (Nemaliales, Rhodophyta), with a description of Akalaphycusgen. nov.
2004Co-Authors: John M. Huisman, Isabella A. Abbott, Alison R. SherwoodAbstract:A morphological and gene sequence study has shown the red algal genus Stenopeltis to be a member of the Liagoraceae (Nemaliales), not the Polyidaceae (Gigartinales) where it was placed after being segregated from Rhodopeltis. Post-fertilization events in Stenopeltis gracilis (the type of the genus) include a spreading, diffuse gonimoblast arising directly from the zygote (= post-fertilization carpogonium), and no auxiliary cells, features characteristic of the Liagoraceae. Moreover, phylogenetic analyses based on LSU (large subunit) rDNA sequences clearly place Stenopeltis in a clade with members of the Liagoraceae. These observations are at odds with the existing taxonomic placement of the genus and a re-interpretation of earlier observations purporting to show the presence of auxiliary cells is presented. The morphology and reproduction of the three species currently attributed to the genus, S. gracilis (the type), S. setchelliae, and S. liagoroides, are described. LSU sequences as well as carpogonial branch and cystocarp morphology of S. setchelliae are distinct from those of S. gracilis (the type), and the segregate genus Akalaphycus is proposed to accommodate S. setchelliae and S. liagoroides.
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Morphology, reproduction, and the 18S rRNA gene sequence of Pihiella liagoraciphila gen. et sp. nov. (Rhodophyta), the so-called 'monosporangial discs' associated with members of the Liagoraceae (Rhodophyta), and proposal of the Pihiellales ord. nov.
Journal of Phycology, 2003Co-Authors: John M. Huisman, Alison R. Sherwood, Isabella A. AbbottAbstract:Pihiella liagoraciphila gen. et sp. nov. (Rhodophyta) is described for a minute endo/epiphyte that is commonly associated with members of the Liagoraceae (Nemaliales, Rhodophyta). Algae are discoid or subspherical and grow to a maximum diameter of 400 μm. Attachment is via isolated elongate rhizoids that penetrate into the loosely filamentous structure of the host or by a pad of several coalesced rhizoids where the host has a more cohesive cortex. Elongate surface hairs are common. Gametophytes are dioecious, the spermatangia arising on surface cells, and carpogonia with elongate trichogynes borne directly on undifferentiated surface supporting cells. Large sporangia form on stalk cells across the upper surface of the plants, these appearing to be either monosporangial or the result of fertilization of the carpogonia and equivalent to undivided zygotosporangia. Carposporophytes and tetrasporangia are unknown. 18S rRNA gene sequence analyses indicate that Pihiella constitutes a clade of long branch length most closely related to the Ahnfeltiales. The unique morphology and reproduction of Pihiella, combined with a substantial genetic divergence from the Ahnfeltiales, suggest that it is sufficiently distinct to warrant placement in a new family and order. We therefore describe the family Pihiellaceae and the order Pihiellales to accommodate the new genus.
