Paul W. Gabrielson

Systematics of red algae (Rhodophyta)

Red algal systematics is in a state of flux unparalleled since the early decades of this century. Ultrastructural and biochemical studies are providing features for a revised classification at ordinal and supraordinal ranks, whereas characters of vegetative and reproductive morphology continue to establish discontinuities among taxa at lower ranks. Cytological, biosystematic, and chemotaxonomic contributions are viewed as useful in defining relationships at specific and infraspecific ranks. Chemotaxonomic studies, depending on the properties of the taxa that are being studied, are applicable at all taxonomic levels. The taxonomic importance of life histories and themes of vegetative morphology, including spore germination, heterotrichy, initiation and differentiation of thalli are discussed at length. Homologies of auxiliary cells, carpogonial branches, and connecting filaments are examined in the context of relationships among Corallinales, Cryptonemiales, Gigartinales, and Rhodymeniales, and their inclu...

Morphometric and molecular analyses confirm two distinct species of Calliarthron (Corallinales, Rhodophyta), a genus endemic to the northeast Pacific

Gabrielson P.W., Miller K.A. and Martone P.T. 2011. Morphometric and molecular analyses confirm two distinct species of Calliarthron (Corallinales, Rhodophyta), a genus endemic to the northeast Pacific. Phycologia 50: 298–316. DOI: 10.2216/10-42.1 Phylogenetic analyses of rbcL sequences demonstrate that Calliarthron as currently constituted is paraphyletic. Calliarthron yessoense and C. latissimum from the northwest Pacific belong in Alatocladia and are conspecific. After the transfer of C. yessoense and C. latissimum, Calliarthron is monophyletic, known only from the northeast Pacific and comprises two species, C. cheilosporioides and C. tuberculosum, which are distinct morphologically, biogeographically and by molecular sequence. Sequence data for the types of C. regenerans and C. setchelliae confirm that they are heterotypic synonyms of C. tuberculosum. Lectotypes are designated for C. cheilosporioides, C. regenerans and C. setchelliae. A morphometric analysis shows that three measured characters reliably distinguish C. cheilosporioides from C. tuberculosum. Alatocladia is monophyletic, known only from the northwest Pacific and comprises two species, A. modesta and A. yessoensis, which are distinct morphologically, biogeographically and by molecular sequence. rbcL sequence data of the type species of Alatocladia, Bossiella, Calliarthron and Chiharaea confidently differentiate these genera with strong bootstrap support.

Minimally destructive sampling of type specimens of Pyropia (Bangiales, Rhodophyta) recovers complete plastid and mitochondrial genomes

Plant species, including algae and fungi, are based on type specimens to which the name of a taxon is permanently attached. Applying a scientific name to any specimen therefore requires demonstrating correspondence between the type and that specimen. Traditionally, identifications are based on morpho-anatomical characters, but recently systematists are using DNA sequence data. These studies are flawed if the DNA is isolated from misidentified modern specimens. We propose a genome-based solution. Using 4 × 4 mm2 of material from type specimens, we assembled 14 plastid and 15 mitochondrial genomes attributed to the red algae Pyropia perforata, Py. fucicola, and Py. kanakaensis. The chloroplast genomes were fairly conserved, but the mitochondrial genomes differed significantly among populations in content and length. Complete genomes are attainable from 19th and early 20th century type specimens; this validates the effort and cost of their curation as well as supports the practice of the type method.

The nature of the ancestral red alga: Inferences from a cladistic analysis

A cladistic analysis of the orders of Rhodophyta is presented. Sixteen taxa and 34 characters comprise the data matrix. Included in the analysis are biochemical and ultrastructural features of pigments, cell walls, cell organelles, mitosis and pit connections as well as vegetative and reproductive characters. The traditional recognition of two classes or subclasses, Bangiophycidae and Florideophycidae, is not supported regardless of whether Porphyridiales, Rhodochaetales or Bangiales is designated the outgroup. Florideophycidae, however, appears to be monophyletic with Bangiales as its sister group. Relationships among taxa with one or two plug cap layers, i.e. Acrochaetiales, Palmariales, Corallinales, Nemaliales, Batrachospermales, Gelidiales and Hildenbrandiales are unresolved. Rhodochaetales, Bangiales and possibly Erythropeltidales are monophyletic, but Porphyridiales is polyphyletic. The class Cyanidiophyceae is not recognized and the included genera are considered to be unicellular red algae belonging to Porphyridiales. Taxa that have been proposed as sister groups for red algae, including Cyanobacteria, Cryptophyta, Glaucophyta and Chlorophyta, and Ascomycetes and Basidiomycetes are discussed in relation to the proposed phylogeny of Rhodophyta.

A new order of red algae based on the Peyssonneliaceae, with an evaluation of the ordinal classification of the Florideophyceae (Rhodophyta)

Abstract The Peyssonneliaceae Denizot comprises a worldwide group of non-calcified or calcified, crust-forming red algae found in diverse, intertidal to deep subtidal marine habitats. Eight genera have been recognized in the family, with Peyssonnelia Decaisne having the largest number of species. Both comparative morphology and rbcL and nuclear LSU rDNA sequence data support the monophyly of the family and show that it cannot be maintained in the order Gigartinales Schmitz. A new order, Peyssonneliales, is herein proposed to accommodate the Peysonneliaceae, with only two of the genera (i.e., Peyssonnelia and Sonderopelta), and its relationship to the other red algal orders is discussed. We also propose the transfer of one species, Peyssonnelia capensis Montagne to Sonderopelta Womersley & Sinkora.

ULTRASTRUCTURE OF VEGETATIVE ORGANIZATION AND CELL DIVISION IN THE UNICELLULAR RED ALGA DIXONIELLA GRISEA GEN. NOV. (RHODOPHYTA) AND A CONSIDERATION OF THE GENUS RHODELLA1

This study suggests that the genus Rhodella be restricted to that set of features currently observed only in Rhodella maculata Evans and Rhodella violacea (Korn‐mann) Wehrmeyer, that a new genus Dixoniella be established to accommodate the unicellular red alga, Rhodella grisea (Geitler) Fresnel, Billard, Hindák et Pekár‐ková, and that Rhodella cyanea Billard et Fresnel be further studied for probable reclassification. These conclusions are based on ultrastructural comparisons of Dixoniella grisea with published information on the genus Rhodella. The presence of thylakoids in the pyrenoid, a peripheral encircling thylakoid in the chloroplast, a dictyosome/nuclear envelope association, and the lack of a specialized pyrenoid/nucleus association in D. grisea separate this alga from the genus Rhodella. Cell division in D. grisea is not demonstrably different from that in Rhodella, although the unusually well‐defined material of the presumptive microtubule organizing center (MTOC) made it possible to follow the development and behavior of the MTOC to a greater degree than in previously studied red algal cells. The surprising amount of conformity in cell division characters between D. grisea and the genus Rhodella prompted a comparison of cell division characteristics in all red algal unicells studied to date.

Molecular sequencing of Northeast Pacific type material reveals two earlier names for Prionitis lyallii, Prionitis jubata and Prionitis sternbergii, with brief comments on Grateloupia versicolor (Halymeniaceae, Rhodophyta)

P.W. Gabrielson. 2008. Molecular sequencing of Northeast Pacific type material reveals two earlier names for Prionitis lyalii, Prionitis jubata and Prionitis sternbergii, with brief comments on Grateloupia versicolor (Halymeniaceae, Rhodophyta). Phycologia 47: 89–97. DOI: 10.2216/04-43.1 William Henry Harvey described seven varieties of his new species Prionitis lyallii on the basis of material collected by Dr. David Lyall at Esquimalt (Vancouver Island), British Columbia, Canada and by C. B. Wood in the Strait of Juan de Fuca. Labeled specimens of four of the varieties (depauperata, dilitata, intermedia and normalis) that were located in Harveys herbarium (Trinity College Dublin) all represent the same species on the basis of internal transcribed spacer 1 and partial rbcL sequences. The specimen labeled var. normalis (P. lyallii var. lyallii) is selected as the lectotype of the species, and it is recommended that no varieties be recognized formally or informally. When J. Agardh erected Prionitis in 1851, Prionitis jubata and Prionitis sternbergii were among the nine species recognized, but both names fell into disuse, the former out of neglect, although it was said to have been collected at Sitka, Alaska, USA, and the latter due to uncertainty about its identity and provenance. Type material of P. jubata, Sphaerococcus sternbergii, the basionym of P. sternbergii, and type material of P. lyallii have identical partial rbcL sequences. Lectotypes are designated for each species. On the basis of the principle of priority, the correct name for this common Northeast Pacific species is P. sternbergii. Grateloupia versicolor, believed to have been collected at Punta St. Agustín, Oxaca, Mexico and with which P. sternbergii had at one time been placed into synonymy, is a distinct species. Haenke, one of two botanists on the Malaspina expedition, collected P. sternbergii in 1791 either in Nootka Sound (Vancouver Island), British Columbia, Canada or from Monterey, California, USA.

A cladistic analysis of Rhodophyta: Florideophycidean orders

A cladistic analysis of the orders of red algae is presented that concentrates on relationships among florideophyte taxa. The data matrix comprises 35 characters and 15 taxa. Biochemical and ultrastructural characters as well as features of vegetative and reproductive morphology and life history were used. Based on a previous cladistic analysis, Erythropeltidales are used as the outgroup to polarize characters among florideophyte orders. Batrachospermales, Ceramiales, Corallinales, Gelidiales, Hildenbrandiales and Nemaliales appear monophyletic, as do Palmariales with the possible exception of one or two genera. Recognition of Acrochaetiales and Bonnemaisoniales is supported, even though the former may be paraphyletic and the latter polyphyletic based on the inclusion of Naccariaceae. Gigartinales appear to be paraphyletic, and relationships among the constituent families need to be resolved to determine the status of the order. Rhodymeniales may not merit ordinal recognition, as all of the synapomorphies...

Molecular-assisted alpha taxonomy reveals pseudocryptic diversity among species of Bossiella (Corallinales, Rhodophyta) in the eastern Pacific Ocean

Abstract: A floristic survey of the red algal genus Bossiella was conducted using molecular-assisted alpha taxonomy (MAAT). The MAAT approach used DNA sequence data as a first pass to assess species diversity followed by additional study including detailed morphological observations to delimit species. In addition, type specimen sequencing was conducted to apply existing species names to genetic groups. Four Bossiella species were recognised in the eastern Pacific Ocean based on morphology, but a genetic screen using a DNA barcode marker, mitochondrial cytochrome c oxidase subunit 1 (COI-5P), showed 17 genetic species groups. Due to the large number of species requiring taxonomic assessment, we focused this study on species with predominantly dichotomous branching, that is, the recognised morphospecies B. californica and B. orbigniana. DNA sequences from three loci, psbA, rbcL and COI-5P, resolved five species: B. californica, B. dichotoma, B. schmittii, Bossiella heteroforma sp. nov. and B. orbigniana (the only species with a type locality not in the northeast Pacific). Morphology alone was an inadequate discriminator of these species, but incorporating distribution and habitat data facilitated identification of some species without DNA sequencing. All of these species were widely distributed in the northeast Pacific Ocean, from at least northern British Columbia, Canada, to Monterey Bay, California, USA, with two reaching Baja California Norte, Mexico.

MORPHOLOGY AND TAXONOMY OF MERISTIELLA GEN. NOV. (SOLIERIACEAE, RHODOPHYTA) 1

Eucheuma acanthocladum (Harvey) J. Agardh, E. gelidium (J Agardh) J. Agardh, E. echinocarpum Areschoug and E. schrammii(P. et H. Crouan) J. Agardh from the tropical and warm temperate waters of the western Atlantic Ocean and Caribbean Sea are transferred to a new genus, Meristiella. Meristiella exhibits the following Unique combination of characters among genera in the Solieriaceae: (1) rotated periaxial cells, (2) a loosely filamentous medulla. (3) an auxiliary cell complex, (4) Single and twin connecting filaments and (5) spinose cystocarps composed of a central, small‐celled placentum, based on its reproductive features, Meristiella. is assigned to the tribe Agardhielleae. Culture experiments and herbarium studies provide evidence that E, gelidium and E. acantghocladum are conspecific. Lectotypes are designated for the included species.