Judy E. Broom

A reassessment of the taxonomic status of Porphyra suborbiculata, Porphyra carolinensis and Porphyra lilliputiana (Bangiales, Rhodophyta) based on molecular and morphological data

We examined three species of diminutive Porphyra, Porphyra suborbiculata Kjellman from the North Pacific, Porphyra lilliputiana W. A. Nelson, G. A. Knight et M. W. Hawkes from the South Pacific, and Porphyra carolinensis Coll et J. Cox from the western North Atlantic. These taxa were compared in terms of morphology, habitat data and sequence haplotypes of nuclear small subunit rDNA (SSU) and internal transcribed spacers of the nuclear rDNA cistron (ITS). These three species have similar morphologies and growth habits, and share very similar type descriptions and habitat records. Haplotype variation was found within the 11 samples of P. lilliputiana we examined and within P. suborbiculata samples from two locations, but the single P. carolinensis haplotype (from collections from two separate locations) was identical to one found in several widespread P. lilliputiana samples. Unrooted phylogenetic trees based on sequence data do not support any of the three species as being a monophyletic group. We conclude that these three taxa represent a single species with the oldest name P. suborbiculata having nomenclatural priority. It is likely that P. suborbiculata has recently been introduced to the western Atlantic from the Pacific region.

Species recognition in New Zealand Porphyra using 18S rDNA sequencing

The long geographic isolation of New Zealand, an archipelago with a large latitudinal range (29°to 54°S) and an extensive coastline, has resulted in a high level of endemism in both land and coastal marine flora. The genus Porphyra in NZ is represented by 5 epiphytic species and a number of epilithic species, many of which are undescribed. Systematic studies aimed at understanding variation inmorphology and life history are underway, and have led to the description of a number of new species. The present study uses sequence data from the18S rDNA locus to investigate genetic variation in New Zealand Porphyra. Sequences have been fully determined for 10 epilithic species. A subset of these data has been shown to be sufficient to distinguish established taxa and to identify new entities. Our data indicate that New Zealand harbours at least 12 epilithic species of Porphyra, establishing the NZ coastline as a repository of diversity for this genus. Phylogenetic trees based on division in complete 18S rDNA sequence data show a deep division in the genus that is not obviously correlated with existing morphological characters, and indicate that representatives of the New Zealand flora have undergone long reproductive isolation.

Phylogenetic relationships and generic concepts in the red order Bangiales: challenges ahead

Wendy A. Nelson, Tracy J. Farr and Judy E.S. Broom. 2006. Phylogenetic relationships and generic concepts in the red order Bengiales: challenges ahead. Phycologia 45: 249–259. DOI: 10.2216/05-26.1 Over the past decade molecular sequence data and phylogenetic analyses have provided strong evidence that the order Bangiales is monophyletic, but that Porphyra and Bangia as currently understood are not. Previous research on the Bangiales has focused primarily on taxa from the North Pacific and North Atlantic. Recent exploration of Bangiales diversity in other regions, particularly the southern hemisphere, has revealed deep divergences in the order in phylogenetic analyses employing the slowly evolving 18S rRNA gene. The presence of high diversity in New Zealand raises the prospect that the southern hemisphere, and particularly eastern Gondwana, is not only a centre of diversity but a centre of origin for the Bangiales. Although the need for new generic concepts within this order is clear, it is our conclusion that approaches to revising the Bangiales based solely on regional approaches will not succeed: the completion of a modern and robust taxonomic revision of this order requires a global collaborative effort. Enhanced taxon sampling and verifiable application of names, based on vouchered specimens, will be essential for this to be achieved. The determination of phylogenetic relationships in the Bangiales has implications for the qua.gification of biodiversity. The number of taxa in the evolutionarily diverse Bangiales has been significantly underestimated, and the diversity in this group has been obscured by the recognition of only two genera. Based on the analyses completed to date, in a revised Bangiales there will be at least 10 genera, 5 of which are currently recognised (Bangia, Dione, Minerva, Pseudobangia and Porphyra), as well as further genera yet to be circumscribed. The majority of species currently placed in Porphyra, including species of commercial value, will not remain in Porphyra sensu stricto.

Ulva, Umbraulva and Gemina: genetic survey of New Zealand taxa reveals diversity and introduced species

The genetic diversity of the green algal genus Ulva sensu lato in the New Zealand region was surveyed, examining rbcL sequences of 581 samples from a wide geographical range. Twenty-four genetically distinct taxa were discovered in New Zealand waters, belonging to three genera–Ulva (19 species), Umbraulva (four species) and Gemina (one species). Of the 19 species of Ulva reported here, 13 could be identified to the species level based on morphological and genetic data. The remaining six species cannot currently be assigned to known species groups due to a lack of close homology with sequences in GenBank. These species may include undescribed endemic taxa, recognised taxa for which rbcL sequences are not yet available, or may represent cryptogenic species. The genus Umbraulva is recorded for the first time for the New Zealand region and for the Southern Hemisphere. Of the four species distinguished, one is considered to be introduced to the region and the other three are undescribed indigenous taxa. Subantarctic samples provide the first evidence of the genus Gemina since its description in 1952: sequence data confirmed that Gemina is distinct from Ulva and Umbraulva. A number of the species identified in this study can be distinguished through a combination of growth form, morphological, ecological and distributional characters. However there remain considerable problems in distinguishing a number of other species by morphological characters alone. Based on information such as distribution in New Zealand (percentage of samples occurring in highly modified environments and/or areas with frequent vessel traffic), as well as the genetic similarity of New Zealand samples to material from overseas, we have concluded that at least five species have been introduced to the New Zealand region: Ulva armoricana, U. californica, U. flexuosa, U. lactuca and Umbraulva olivascens.

Four new species of Porphyra (Bangiales, Rhodophyta) from the New Zealand region described using traditional characters and 18S rDNA sequence data

Abstract Four new species of the genus Porphyra (Bangiales, Rhodophyta) from the New Zealand region are described: P. cinnamomea W.A. Nelson, P. coleana W.A. Nelson, P. rakiura W.A. Nelson and P. virididentata W.A. Nelson. These species are monostromatic, monoecious, and grow in the intertidal zone, predominantly on rock substrata. They can be distinguished from each other by traditional characters including morphology (particularly the microscopic arrangement of cells along the thallus margin, thallus shape, size and colour), geographical, ecological and seasonal distribution patterns, and chromosome numbers ( P. cinnamonea n = 3, P. coleana n = 4, P. rakiura n = 2, P. virididentata n = 3). These four species can be distinguished by a unique nucleotide sequence at the 18S rDNA locus: they can be separated on the basis of a subset of approximately 500 bp of 18S rDNA sequence data downstream of primer G06, corresponding to variable region V9. This constitutes an important taxonomic character. These four species are known currently solely from the New Zealand region.

Structural analysis of carrageenan from farmed varieties of Philippine seaweed

Abstract Kappaphycus alvarezii, Eucheuma denticulatum and, more recently, Kappaphycus sp. ‘Sacol’ variety, are the carrageenan-containing red seaweeds currently farmed in the Philippines. The Kappaphycus sp. ‘Sacol’ variety is of particular interest to the Philippine seaweed industry because of its improved resistance to ‘ice-ice’ disease and its fast growing characteristics. Here we report on the detailed chemical analysis of the carrageenan from this species. The native and alkali-modified carrageenans from Kappaphycus sp. ‘Sacol’ variety were characterized by FT-IR, 1H and 13C NMR spectroscopy, and constituent sugar and methylation analyses and were compared to those from K. alvarezii, K. cottonii and Eucheuma denticulatum. The three Kappaphycus species contained predominantly κ-carrageenan with low levels of ι-carrageenan, methylated carrageenan and μ-precursor residues, while Eucheuma denticulatum contained predominantly ι-carrageenan with significant amounts of ν-precursor residues. Taxonomic classification of Kappaphycus species based on morphology has proved to be difficult because of their known plasticity. Molecular analysis using the rbcL sequence revealed that the Kappaphycus sp. ‘Sacol’ variety is most likely a form of K. cottonii.

Phylogenetic diversity in South African Porphyra (Bangiales, Rhodophyta) determined by nuclear SSU sequence analyses

Specimens of Porphyra were collected at 10 sites along the western, southern and eastern Cape coasts of South Africa during late January to early February 2001. Sequence data from the variable V9 region of the nuclear small subunit rDNA (nSSU) locus were determined for 45 specimens. These data identified 11 distinct entities each with unique V9 sequences. Phylogenetic analyses incorporating sequences of Porphyra and Bangia from throughout the world revealed that eight of the entities examined in this study form a monophyletic group, apparently endemic to the southern African region. The other three entities exhibited no close phylogenetic relationship either with each other or with the other South African taxa. This survey indicates that the southern African coast is a repository of greater taxonomic diversity for this genus than has been previously reported.

Relationships of the Porphyra (Bangiales, Rhodophyta) flora of the Falkland Islands: a molecular survey using rbcL and nSSU sequence data

The phylogenetic relationships of Porphyra collected from the Falkland Islands have been examined using molecular data from two loci, the plastid rbcL gene and the nuclear nSSU gene, in conjunction with morphological observations. Nine species have been distinguished, belonging to four distinct lineages within the Bangiales, differing from one another by 16–137 substitutions in the rbcL gene. One species is closely related to P. amplissima, a north Atlantic taxon, three are resolved in a clade that includes several species from New Zealand, Australia and South Africa, as well as P. umbilicalis, whereas four others are more closely related to Southern Ocean species, including P. cinnamomea, P. virididentata and several as yet unnamed taxa from New Zealand, Australia and South Africa. Three species, one of which we identify as P. columbina, appear to be widely distributed in the Southern Ocean, with representatives on the Falkland Islands and on islands of the Australian and New Zealand subantarctic.

Dione and Minerva, two new genera from New Zealand circumscribed for basal taxa in the Bangiales (Rhodophyta)

W.A. Nelson, T.J. Farr and J.E.S. Broom. 2005. Dione and Minerva, two new genera from New Zealand circumscribed for basal taxa in the Bangiales (Rhodophyta). Phycologia 44: 139–145. Two new monospecific genera of filamentous red algae from New Zealand are described, Dione arcuata and Minerva aenigmata (Bangiales, Rhodophyta). Although these taxa conform to the morphological concept of the genus Bangia that is in current use, analyses of nuclear small-subunit ribosomal RNA gene (nSSU) sequences have revealed that these taxa are basal in the order Bangiales and differ significantly from each other and all other filamentous species in the order Bangiales for which nSSU sequence data exist (Broom et al. 2004). Dione arcuata can be distinguished in the field by its width, growth habit and the niche it occupies in the upper subtidal zone, whereas Minerva aenigmata is found on upper intertidal rocks in areas of sand abrasion, and is indistinguishable morphologically from other filamentous Bangiales taxa.

The identity of Porphyra columbina (Bangiales, Rhodophyta) originally described from the New Zealand subantarctic islands

Porphyra columbina Mont. (Bangiales, Rhodophyta) was collected in 1840 from the Auckland Islands in the New Zealand subantarctic region. This name has been applied to bladed Bangiales exhibiting a wide range of morphological forms, and found throughout the New Zealand region and in much of the southern hemisphere, particularly in Australia and Chile. By using morphological and anatomical characters as well as nSSU and rbcL sequence data, Montagne’s description of P. columbina is re-examined in the light of recent collections from the New Zealand region and the Southern Ocean. We conclude that P. columbina is primarily distributed in cold temperate conditions, including the Auckland, Campbell, Antipodes, Chatham and Falkland Islands, and is only rarely present on mainland New Zealand. Specimens from the type locality and other subantarctic locations have a rosette to ovate growth form and are typically less than 5 cm in height/width, with specimens from more northern locations including some ribbon-like growth forms. Thalli are purple to grey, bleaching golden green. Mature specimens have a distinctly spotted appearance, with conspicuous large, purple–red clusters of phyllospores and golden marginal areas of spermatangia. Five unique rbcL haplotypes, differing by 1–6 substitutions, were obtained from 26 specimens, with the most common haplotype found in specimens from the Auckland, Campbell and the Falkland Islands.