D. Wilson Freshwater

Morphology and molecular phylogeny of the marine algal order Gelidiales (Rhodophyta) from New South Wales, including Lord Howe and Norfolk Islands

Fifteen species in seven genera of the marine benthic red algal order Gelidiales are reported from the New South Wales coast including Lord Howe Island and Norfolk Island. Critical sampling, a re-examination of herbarium specimens filed in the Royal Botanic Gardens Sydney and the University of Melbourne, and molecular sequencing of most of the species has determined that many of the previous identifications from this region of the Pacific were incorrect. Gelidium pusillum (Stackhouse) Le Jolis, once widely reported from this coast, is shown not to occur here and the specimens on which these misidentifications were made have proved to represent either new species or previously described species. Similarly, records of Gelidium australe J. Agardh have been found to represent misidentification of the formerly New Zealand endemic Gelidium allanii V.J.Chapman, and specimens identified as Gelidium caulacantheum J. Agardh actually represent the new species Gelidium hommersandii sp. nov. Previously recorded species verified in this study are Capreolia implexa Guiry & Womersley, Gelidiella acerosa (Forsskal) Feldmann & G.Hamel, Gelidium maidenii Lucas, Pterocladia lucida (Turner) J. Agardh, Pterocladiella caerulescens (Kutzing) Santelices & Hommersand [as Pterocladia caerulescens (Kutzing) Santelices], Pterocladiella capillacea (Gmelin) Santelices & Hommersand [as Pterocladia capillacea (Gmelin) Bornet], and Ptilophora pectinata (A. & E.S. Gepp) R.E.Norris. These species are described and illustrated in detail along with previously unreported reproductive structures. Three species are newly recorded for the New South Wales mainland [Parviphycus antipae Celan, Gelidium crinale (Turner) Gaillon, and Pterocladiella caloglossoides (Howe) Santelices], and two species (Gelidium isabelae W.R.Taylor and Gelidium allanii V.J.Chapman) represent new records for the Australian continent. In addition, three new species are described: Gelidium bernabei sp. nov., Gelidium declerckii sp. nov., and Gelidium hommersandii sp. nov.

Taxonomic notes on Caribbean Neosiphonia and Polysiphonia (Ceramiales, Florideophyceae): five species from Florida, USA and Mexico

Abstract Molecular-assisted identification using plastid-encoded rbcL and mitochondrion-encoded COI loci identified five species of Polysiphonia sensu lato from 16 Florida and Caribbean Mexico samples. Morphological character states were examined and used to identify these species as Neosiphonia bajacali comb. nov., N. echinata comb. nov., N. sphaerocarpa, N. tepida, and Polysiphonia anomala. Descriptions are provided and the phylogenetic relationships of the five species were determined through maximum likelihood analyses of rbcL and nuclear-encoded SSU sequence data. Neosiphonia bajacali and N. echinata had a combination of character states described for Neosiphonia: rhizoids cut-off from pericentral cells, lateral branch or trichoblast initials on every segment in a spiral pattern, tetrasporangia in spiral series, and spermatangial stichidia developing as bifurcations of trichoblasts, and these new combinations are proposed. Examination of N. echinata, P. fracta and North Carolina specimens identified as P. breviarticulata revealed no significant morphological differences. Polysiphonia fracta is proposed as a synonym of N. echinata and the presence of P. breviarticulata within the western Atlantic is questioned. This is the first report of N. bajacali from the Caribbean and the first report of N. echinata from Caribbean Mexico.

Consistency of morphological characters used to delimit Polysiphonia sensu lato species (Ceramiales, Florideophyceae): analyses of North Carolina, USA specimens

B. Stuercke & D.W. Freshwater. 2008. Consistency of morphological characters used to delimit Polysiphonia sensu lato species (Ceramiales, Florideophyceae): analyses of North Carolina, USA specimens. Phycologia 47: 541–559. DOI: 10.2216/08-09.1 Polysiphonia sensu lato (including Neosiphonia) is a genus within the red algal order Ceramiales that includes over 200 current species and is distributed throughout the world. The consistency of morphological characters commonly used to distinguish species was tested by analyses of these characters within eight North Carolina, USA, species of P. sensu lato objectively defined by rbcL sequence analysis. Examination of 22 characters found five to be consistent and useful for identifying species: number of pericentral cells, rhizoid–pericentral cell connection, relationship of lateral branches to trichoblasts, spermatangial axes development, and arrangement of tetrasporangia. Character states for the pattern and occurrence of trichoblasts and scar cells, the type of the holdfast, and formation of cicatrigenous branches may also help to strengthen the distinctions among species; although, some of these characters were not uniformly consistent. These morphological findings may be applicable to the study of P. sensu lato from other regions as well. The eight North Carolina species were resolved in a variety of positions within the Polysiphonia sensu lato rbcL tree, and integrated molecular and morphological analyses indicated that two, Polysiphonia denudata and Polysiphonia urceolata, have been historically misidentified.

Nuclear 18S rRNA gene sequence analyses indicate that the Mastophoroideae (Corallinaceae, Rhodophyta) is a polyphyletic taxon

Abstract Nuclear small subunit ribosomal RNA (18S rRNA) gene sequences were determined for six species representing three genera classified within the Mastophoroideae, and also for two species of Amphiroa (Lithophylloideae). These data were combined with previously published 18S rRNA sequences for 38 other coralline species and analysed (1) to determine the phylogenetic position of the Mastophoroideae within the Corallinaceae and (2) to examine relationships among Hydrolithon, Metamastophora, Neogoniolithon and Spongites. Trees derived from parsimony and maximum likelihood analyses of these data indicate that the Mastophoroideae is not monophyletic. Instead, our data suggest that the group is polyphyletic and includes species belonging to four distinct evolutionary lineages. For example, Neogoniolithon spp. were associated with geniculate members of the Corallinoideae, and Hydrolithon was resolved as sister to the geniculate genus Metagoniolithon. We demonstrate that each of the four ‘mastophoroid’ lineages share a number of vegetative and reproductive features with their respective sister taxa. Together the molecular and morphological data imply that the Mastophoroideae is not monophyletic and that genera placed in this taxon might more naturally be classified in other subfamilies. Also, on the basis of our findings, Porolithon pachydermum is transferred to Hydrolithon as H. pachydermum (Foslie) Bailey, Gabel & Freshwater.

Quantification and characterization of nuclear genomes in commercial red seaweeds: Gracilariales and Gelidiales

Nuclear genome profiles were developed for representative species of the Gelidiales and Gracilariales using information from present and previous studies of cytogenetics, cytophotometry and DNA reassociation kinetics. Results indicate that species of Gracilaria and Gracilariopsis are characterized by distinct chromosome complements of n = 24 and n = 32, respectively, a narrow range of small genome sizes (2C = 0.35–0.45 pg) and a wide range of values for repeated and unique genome sequences. In contrast, the Gelidiales investigated are characterized by a wide range of chromosome complements, n = 6–29, a wider range of genome sizes (2C = 0.42–0.68 pg) and a large proportion of unique genome sequences. Nuclear genome sizes for species of the Gelidiales and Gracilariales are compared with estimates of other red algal orders including the Bangiales, Ceramiales and Gigartinales.

Four Gelidiales (Rhodophyta) new to southern Africa, Aphanta pachyrrhiza gen. et sp. nov., Gelidium profundum sp. nov., Pterocladiella caerulescens and P. psammophila sp. nov

E.M. Tronchin and D.W. Freshwater. 2007. Four Gelidiales (Rhodophyta) new to southern Africa, Aphanta pachyrrhiza gen. et sp. nov., Gelidium profundum sp. nov., Pterocladiella caerulescens and P. psammophila sp. nov. Phycologia 46: 325–348. DOI: 10.2216/06-73.1 Four Gelidiales taxa are reported for the first time from the northern KwaZulu-Natal coast of South Africa and the southern Mozambican coast. Three of these taxa are new to science, namely, Aphanta pachyrrhiza gen. et. sp. nov., Gelidium profundum sp. nov. and Pterocladiella psammophila sp. nov. The fourth is the first report of Pterocladiella caerulescens from the southern African coast. These species were identified using an integrated taxonomic approach that employed DNA sequence and morphological analyses. The southern African coast continues to be an area of high Gelidiales diversity with six genera and 30 species currently reported from this region.

Polysiphonia sensu lato (Ceramiales, Florideophyceae) species of Caribbean Panama including Polysiphonia lobophoralis sp. nov. and Polysiphonia nuda sp. nov .

Abstract Only two species of Polysiphonia sensu lato (predominately species of Polysiphonia and Neosiphonia) have been reported from Caribbean Panama. In contrast, 16 species are documented from the neighboring countries of Costa Rica and Colombia. Molecular-assisted identification using plastid-encoded ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) and mitochondria-encoded cytochrome coxidase subunit I gene (COI) loci identified 14 species from 38 samples collected along the Caribbean coast of Panama. Morphological character states were examined and used to identify each sample, and phylogenetic relationships among these species were estimated through maximum likelihood analyses of rbcL and nuclear-encoded SSU sequence data. Neosiphonia ferulaceae, N. tongatensis, Polysiphonia binneyi, P. havanensis, P. macrocarpa, P. pseudovillum, P. schneideri, P. subtilissima, and two species that could only be identified as P. cf. sertularioides are reported for the first time from Panama. Polysiphonia pentamera, a species only known from the eastern Pacific is reported for the first time in the Caribbean, and two new species, P. lobophoralis and P. nuda are described. A key to Caribbean Panama species, descriptions of species morphology and remarks on taxonomy and relationships are provided. These findings demonstrate that previous limited reports of Polysiphonia sensu lato species from Panama resulted from a lack of study, rather than a lack of diversity, within the region.

Nuclear DNA content variation in the freshwater red algal orders Batrachospermales and Thoreales (Florideophyceae, Nemaliophycidae)

D.F. Kapraun, K.S. Braly and D.W. Freshwater. 2007. Nuclear DNA content variation in the freshwater red algal orders Batrachospermales and Thoreales (Florideophyceae, Nemaliophycidae). Phycologia 46: 54–62. DOI: 10.2216/06-18.1 A microspectrophotometric investigation of red algae in the exclusively freshwater orders Batrachospermales and Thoreales was initiated to determine the extent of nuclear DNA content variation and to corroborate the alternation of haploid and diploid nuclear DNA contents in gametophyte and sporophyte life history stages. Partial RuBisCO subunit (rbcL) sequences were generated and included in a larger data set for phylogenetic analyses to explore possible correlations between genome size and evolution. Results of rbcL analyses reflected those of previous studies, including the monophyly of the genus Sirodotia and family Lemaneaceae, and paraphyly of Batrachospermum. Static microspectrophotometry and the DNA-localizing fluorochrome DAPI (4′,6′-diamidodino-2-phenylindole) and red blood cell (chicken erythrocytes) standard were used to estimate nuclear DNA contents for 11 species in 6 genera in the Batrachospermales and the Thoreales. Estimated nuclear DNA content values ranged from 0.23 to 3.20 pg. Both estimated genome sizes and published chromosome numbers suggest a discontinuous distribution that can be explained in terms of ancestral polyploidy events. Results of this study suggest a possible correlation between polyploidy and the expression of the Batrachospermum or Lemanea morphological phenotypes. For isolates of three species, If (fluorescence) levels in 2C nuclei in presumptive gametophytes closely approximated 50% of the 4C values in presumptive sporophytes, consistent with an alternation of ploidy levels in a sexual life history.

Morphology and systematics of Gelidiella tenuissima (Gelidiales, Rhodophyta) from Gran Canaria (Canary Islands, Spain)

Abstract Fertile male gametophytes of Gelidiella tenuissima are described for the first time, from cultured plants collected in Gran Canaria (Canary Islands, Spain). The morphology of male reproductive structures in this species is similar to other gametophytes referred to the Gelidiales, but different from the recently described male gametophyte of the type species of Gelidiella, G. acerosa. Morphological comparisons between these two species, using the male gametophyte and the tetrasporangial stichidia, and also molecular analyses, suggest that two different groups of species are included in the genus Gelidiella.

PROPOSAL OF THE EUPTILOTEAE HOMMERSAND ET FREDERICQ, TRIB. NOV. AND TRANSFER OF SOME SOUTHERN HEMISPHERE PTILOTEAE TO THE CALLITHAMNIEAE (CERAMIACEAE, RHODOPHYTA)1

Morphological and molecular studies demonstrate that the tribe Ptiloteae (Ceramiaceae, Ceramiales) is polyphyletic. The Ptiloteae, sensu stricto, occur only in the Northern Hemisphere and all Southern Hemisphere representatives belong in other tribes. Three genera (Euptilota, Seirospora, and Sciurothamnion) are transferred to the Euptiloteae Hommersand et Fredericq, trib. nov., and the Callithamnieae is revised to include three Ptilota‐like genera, Georgiella, Falklandiella, and Diapse, and two new genera. Heteroptilon Hommersand, gen. nov. is erected to receive Euptilota pappeana Kützing 1849 and Aglaothamnion rigidulum De Clerck, Bolton, Anderson et Coppejans 2004 from South Africa, and Aristoptilon Hommersand et W. A. Nelson, gen. nov. is established to receive Euptilota mooreana Lindauer 1949 from New Zealand. The principal difference between the Euptiloteae and the Callithamnieae is seen in the earliest stages after fertilization. The fertilized carpogonium enlarges and forms a pair of tube‐like protuberances directed toward the auxiliary cells that are cut off as connecting cells in the Euptiloteae, whereas in the Callithamnieae the carpogonium usually divides into two cells, each of which cuts off a small connecting cell that fuses with an adjacent enlarging auxiliary cell. Nuclei are terminal in spermatangia of the Euptiloteae, subtended by mucilaginous vesicles, and are medial in the Callithamnieae situated between apical and basal vesicles. The Euptiloteae and Callithamnieae (including the Ptilota‐like members) are each strongly supported in maximum‐likelihood tree topologies resulting from analyses of combined 18S rDNA, 28S rDNA, 16S rDNA, and rbcL data sets. Their sister relationship is also well supported.