Tracy J. Farr

A NEW LOOK AT AN ANCIENT ORDER: GENERIC REVISION OF THE BANGIALES (RHODOPHYTA)†

The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU (rbcL) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia, and Wildemania. Four of the seven filamentous genera recognized in our analyses already have generic names (Bangia, Dione, Minerva, and Pseudobangia), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbcL sequence data should be obtained so that they can be assigned to the appropriate genus.

A NEW LOOK AT AN ANCIENT ORDER: GENERIC REVISION OF THE BANGIALES (RHODOPHYTA)(1).

The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU (rbcL) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia, and Wildemania. Four of the seven filamentous genera recognized in our analyses already have generic names (Bangia, Dione, Minerva, and Pseudobangia), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbcL sequence data should be obtained so that they can be assigned to the appropriate genus.

Utility of psbA and nSSU for phylogenetic reconstruction in the Corallinales based on New Zealand taxa

A number of molecular studies of the Corallinales, a calcified order of the red algae, have used the conservative nSSU gene to investigate relationships within the order. However interspecific variation at this locus is low for closely related species, limiting resolution of recently diverged groups. In this study, we obtained psbA sequence data from specimens of the order from New Zealand that had been identified according to current taxonomic criteria. We compared phylogenetic analyses based on psbA with those based on nSSU for the same dataset, and also analysed nSSU sequences of the New Zealand material with nSSU sequences of Corallinales taxa from other parts of the world. Our study shows that psbA has considerable potential as a marker for this group, being easily amplified and considerably more variable than nSSU. Combined analyses using both markers provide significant support for relationships at both distal and terminal nodes of the analysis. Our analysis supports the monophyly of all three families currently defined in Corallinales: the Sporolithaceae, Hapalidiaceae and Corallinaceae, and indicates cryptic speciation in Mesophyllum and Spongites.

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.

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.

A new look at an ancient order: generic revision of the Bangiales

The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU (rbcL) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia, and Wildemania. Four of the seven filamentous genera recognized in our analyses already have generic names (Bangia, Dione, Minerva, and Pseudobangia), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbcL sequence data should be obtained so that they can be assigned to the appropriate genus.

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.

Phylogenetic diversity of New Zealand Gelidiales as revealed by rbcL sequence data

Diversity and phylogenetic relationships of New Zealand representatives of the red algal order Gelidiales have been examined using rbcL sequence data. Extensive field collections have been made from throughout the New Zealand region. Six genera have been reported previously from New Zealand (Capreolia, Gelidium, Pterocladia, Pterocladiella, Pterocladiastrum, Ptilophora). This research has revealed species with very restricted local distributions, as well as the discovery of several undescribed, cryptic taxa. The common and widespread Gelidium caulacantheum is confirmed to be more closely related to Capreolia than to other species of Gelidium. The generic concept of Capreolia, based on life history characters, will need to be modified to accommodate additional species possessing “Gelidium” life histories. A species endemic to New Zealand, Gelidium ceramoides, has been found to differ significantly from all other members of the Gelidiales and requires reclassification in another genus and order. Examination of field collections and herbarium specimens in addition to molecular sequence data have led us to conclude that specimens previously placed in the genera Ptilophora and Pterocladiastrum belong within Pterocladia lucida.

Pyrophyllon and Chlidophyllon (Erythropeltidales, Rhodophyta): two new genera for obligate epiphytic species previously placed in Porphyra, and a discussion of the orders Erythropeltidales and Bangiales

Abstract Two new genera, Pyrophyllon and Chlidophyllon, are described to accommodate three species of obligately epiphytic red algae endemic to the New Zealand region, which were previously placed in the genus Porphyra. Although these species all possess rhizoidal holdfasts and packets of spores, and two of the three species produce archeosporangia (characters consistent with the morphological concept of the genus Porphyra), molecular sequence analyses (nuclear small-subunit ribosomal DNA gene) and polysaccharide chemistry data confirm that these epiphytes are more closely related to members of the Erythropeltidales than to the Bangiales. The criteria used to distinguish members of these orders are discussed.