Quantifying pigment content in crustose coralline algae using hyperspectral imaging: A case study with Tethysphytum antarcticum (Ross Sea, Antarctica).

Crustose coralline algae (CCA) are a highly diverse group of habitat-forming, calcifying red macroalgae (Rhodophyta) with unique adaptations to diverse irradiance regimes. A distinctive CCA phenotype adaptation, which allows them to maximize photosynthetic performance in low light, is their content of a specific group of light-harvesting pigments called phycobilins. In this study, we assessed the potential of noninvasive hyperspectral imaging (HSI) in the visible spectrum (400-800 nm) to describe the phenotypic variability in phycobilin content of an Antarctic coralline, Tethysphytum antarcticum (Hapalidiales), from two distinct locations. We validated our measurements with pigment extractions and spectrophotometry analysis, in addition to DNA barcoding using the psbA marker. Targeted spectral indices were developed and correlated with phycobilin content using linear mixed models (R2 = 0.64-0.7). Once applied to the HSI, the models revealed the distinct phycoerythrin spatial distribution in the two site-specific CCA phenotypes, with thin and thick crusts, respectively. This study advances the capabilities of hyperspectral imaging as a tool to quantitatively study CCA pigmentation in relation to their phenotypic plasticity, which can be applied in laboratory studies and potentially in situ surveys using underwater hyperspectral imaging systems.

Investigating seed bank potential of crustose coralline algae using DNA metabarcoding.

To examine the potential for the autogenic ecosystem engineers, crustose coralline algae (CCA), to serve as seed banks or refugia for life stages of other species, it is critical to develop sampling protocols that reflect the diversity of life present. In this pilot study on two shallow water species of CCA collected from Raoul Island (Kermadec Islands; Rangitahua) New Zealand, we investigated two preservation methods (ethanol vs. silica gel), sampled inner and outer regions of the crusts, and used DNA metabarcoding and seven genes/gene regions (16S rRNA, 18S rRNA, 23S rRNA, cox1, rbcL, and tufA genes and the ITS rRNA region) to develop a protocol for taxa identification. The results revealed immense diversity, with typically more taxa identified within the inner layers than the outer layers. As highlighted in other metabarcoding studies and in earlier work on rhodoliths (nodose coralline algae), reference databases are incomplete, and to some extent, the use of multiple markers mitigates this issue. Specifically, the 23S rRNA and rbcL genes are currently more suitable for identifying algae, while the cox1 gene fares better at capturing the diversity present inclusive of algae. Further investigation of these autogenic ecosystem engineers that likely act as marine seed banks is needed.

Levelling-up rhodolith-bed science to address global-scale conservation challenges.

Global marine conservation remains fractured by an imbalance in research efforts and policy actions, limiting progression towards sustainability. Rhodolith beds represent a prime example, as they have ecological importance on a global scale, provide a wealth of ecosystem functions and services, including biodiversity provision and potential climate change mitigation, but remain disproportionately understudied, compared to other coastal ecosystems (tropical coral reefs, kelp forests, mangroves, seagrasses). Although rhodolith beds have gained some recognition, as important and sensitive habitats at national/regional levels during the last decade, there is still a notable lack of information and, consequently, specific conservation efforts. We argue that the lack of information about these habitats, and the significant ecosystem services they provide, is hindering the development of effective conservation measures and limiting wider marine conservation success. This is becoming a pressing issue, considering the multiple severe pressures and threats these habitats are exposed to (e.g., pollution, fishing activities, climate change), which may lead to an erosion of their ecological function and ecosystem services. By synthesizing the current knowledge, we provide arguments to highlight the importance and urgency of levelling-up research efforts focused on rhodolith beds, combating rhodolith bed degradation and avoiding the loss of associated biodiversity, thus ensuring the sustainability of future conservation programs.

Molecular analyses of turf algae reveal a new species and an undetected introduction in the Pterosiphonieae (Rhodomelaceae, Rhodophyta).

Introduced seaweeds and undescribed species often remain undetected because marine regional floras are as yet poorly understood. DNA sequencing facilitates their detection, but databases are incomplete, so their improvement will continue to lead the discovery of these species. Here we aim to clarify the taxonomy of two turf-forming red algal Australian species that morphologically resemble the European Aphanocladia stichidiosa. We also aim to elucidate whether either of these species could have been introduced in Europe or Australia. We studied their morphology, analyzed 17 rbcL sequences of European and Australian specimens, examined their generic assignment using a phylogeny based on 24 plastid genomes, and investigated their biogeography using a taxon-rich phylogeny including 52 rbcL sequences of species in the Pterosiphonieae. The rbcL sequences of one of the Australian species were identical to A. stichidiosa from Europe, considerably expanding its known distribution. Unexpectedly, our phylogenetic analyses resolved this species in the Lophurella clade rather than in Aphanocladia and the new combination L. stichidiosa is proposed. The other Australian species is described as L. pseudocorticata sp. nov. Although L. stichidiosa was originally described in the Mediterranean ca. 70 years ago, our phylogenetic analyses placed it in a lineage restricted to the southern hemisphere, showing that it is native to Australia and introduced to Europe. This study confirms that further work using molecular tools is needed to characterize seaweed diversity, especially among the poorly explored algal turfs, and showcases the usefulness of phylogenetic approaches to uncover introduced species and to determine their native ranges.

Pre-domestication bottlenecks of the cultivated seaweed Gracilaria chilensis.

Gracilaria chilensis is the main cultivated seaweed in Chile. The low genetic diversity observed in the Chilean populations has been associated with the over-exploitation of natural beds and/or the founder effect that occurred during post-glacial colonization from New Zealand. How these processes have affected its evolutionary trajectory before farming and incipient domestication is poorly understood. In this study, we used 2232 single nucleotide polymorphisms (SNPs) to assess how the species' evolutionary history in New Zealand (its region of origin), the founder effect linked to transoceanic dispersion and colonization of South America, and the recent over-exploitation of natural populations have influenced the genetic architecture of G. chilensis in Chile. The contrasting patterns of genetic diversity and structure observed between the two main islands in New Zealand attest to the important effects of Quaternary glacial cycles on G. chilensis. Approximate Bayesian Computation (ABC) analyses indicated that Chatham Island and South America were colonized independently near the end of the Last Glacial Maximum and emphasized the importance of coastal and oceanic currents during that period. Furthermore, ABC analyses inferred the existence of a recent and strong genetic bottleneck in Chile, matching the period of over-exploitation of the natural beds during the 1970s, followed by rapid demographic expansion linked to active clonal propagation used in farming. Recurrent genetic bottlenecks strongly eroded the genetic diversity of G. chilensis prior to its cultivation, raising important challenges for the management of genetic resources in this incipiently domesticated species.

Phymatolithopsis gen. nov. (Hapalidiales, Corallinophycidae, Rhodophyta) based on molecular and morpho-anatomical evidence.

A multigene (psbA, rbcL, 18S rDNA) molecular phylogeny of the genus Phymatolithon showed a polyphyletic grouping of two monophyletic clades within the Hapalidiales. DNA sequence data integrated with morpho-anatomical comparisons of type material and of recently collected specimens were used to establish Phymatolithopsis gen. nov. with three species, P. prolixa comb. nov., the generitype, P. repanda comb. nov. and P. donghaensis sp. nov. Phymatolithopsis is sister to Mesophyllum and occurs in a clade distinct from Phymatolithon and boreal species currently assigned to Lithothamnion. Morpho-anatomically, Phymatolithopsis is comprised of species that are non-geniculate and encrusting, bear epithallial cells with rounded walls (not flared), subepithallial initials that are usually as short as or shorter than their immediate inward derivatives, conceptacle primordia from all stages forming superficially directly from subepithallial initials, mature carposporangial conceptacles with a discontinuous fusion cell, gonimoblast filaments that develop at the margins of the fusion cell around the periphery of the carposporangial conceptacle chambers, and multiporate tetra/bisporangial conceptacles. Phymatolithopsis can be distinguished from Phymatolithon by the origin of its conceptacle primordia, which are initiated superficially, directly from the layer of subepithallial initials below the epithallial cells and the distribution of gonimoblast filaments in carposporangial conceptacles, that are at the margins of the fusion cells.

Corallinapetrales and Corallinapetraceae: A new order and family of coralline red algae including Corallinapetra gabrielii comb. nov.

The coralline algal genus Corallinapetra is currently monospecific and was established on the species Corallinapetra novaezelandiae, known from a single collection from north-eastern New Zealand. On the basis of multi-gene phylogenetic analyses, Corallinapetra has been resolved apart from all currently recognized families and orders within the Corallinophycidae. We analyzed DNA sequence data from the holotype of Lithothamnion gabrielii, which has been considered a heterotypic synonym of L. muelleri, and an unidentified sample collected from Stewart Island in New Zealand, using psbA, rbcL, and COI-5P genes. We also observed detailed morpho-anatomical characters with light and scanning electron microscopy. Our phylogenetic analyses showed that L. gabrielii and the sample from New Zealand belonged to the same clade as Corallinapetra, distinct from other families and orders in the Corallinophycidae. Members of this clade are distinguishable from other families and orders in the Corallinophycidae by possessing sporangia that are surrounded by remnant sterile filaments that are weakly calcified in mature multiporate sporangial conceptacles that produce zonately divided tetrasporangia. Therefore, we propose that Corallinapetra be placed in its own family, Corallinapetraceae and order, Corallinapetrales, and that L. gabrielii should be assigned to Corallinapetra, as C. gabrielii, to reflect their phylogenetic relationships. We also obtained a partial rbcL sequence data from the lectotype of L. muelleri, the generitype of Lithothamnion. Comparison of the L. muelleri type sequence with L. gabrielii unambiguously demonstrated that these two species are not conspecific, and confirm the placement of L. muelleri within the Hapalidiales.

Inorganic carbon utilization of tropical calcifying macroalgae and the impacts of intensive mariculture-derived coastal acidification on the physiological performance of the rhodolith Sporolithon sp.

Fish farming in coastal areas has become an important source of food to support the world's increasing population. However, intensive and unregulated mariculture activities have contributed to changing seawater carbonate chemistry through the production of high levels of respiratory CO2. This additional CO2, i.e. in addition to atmospheric inputs, intensifies the effects of global ocean acidification resulting in localized extreme low pH levels. Marine calcifying macroalgae are susceptible to such changes due to their CaCO3 skeleton. Their physiological response to CO2-driven acidification is dependent on their carbon physiology. In this study, we used the pH drift experiment to determine the capability of 9 calcifying macroalgae to use one or more inorganic carbon (Ci) species. From the 9 species, we selected the rhodolith Sporolithon sp. as a model organism to investigate the long-term effects of extreme low pH on the physiology and biochemistry of calcifying macroalgae. Samples were incubated under two pH treatments (pH 7.9 = ambient and pH 7.5 = extreme acidification) in a temperature-controlled (26 ± 0.02 °C) room provided with saturating light intensity (98.3 ± 2.50 µmol photons m-2 s-1). After the experimental treatment period (40 d), growth rate, calcification rate, nutrient uptake rate, organic content, skeletal CO3-2, pigments, and tissue C, N and P of Sporolithon samples were compared. The pH drift experiment revealed species-specific Ci use mechanisms, even between congenerics, among tropical calcifying macroalgae. Furthermore, long-term extreme low pH significantly reduced the growth rate, calcification rate and skeletal CO3-2 content by 79%, 66% and 18%, respectively. On the other hand, nutrient uptake rates, organic matter, pigments and tissue C, N and P were not affected by the low pH treatments. Our results suggest that the rhodolith Sporolithon sp. is susceptible to the negative effects of extreme low pH resulting from intensive mariculture-driven coastal acidification.

Comparative phylogeography of two Agarophyton species in the New Zealand archipelago.

Molecular studies have reported the coexistence of two species of Agarophyton in New Zealand: the newly described A.transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more widespread A.chilense. Here, we compared the distribution, genetic diversity, and structure of both Agarophyton species throughout the archipelago using sequences of the nuclear Internal Transcribed Spacer 2 (ITS2) marker. Agarophyton chilense's distribution was continuous and extensive along the North and South Islands, Stewart Island, and Chatham Island, and the genetic clusters were mostly concordant with boundaries between biogeographic regions. In contrast, specimens of A.transtasmanicum were collected in four sites broadly distributed in both the North and South Islands, with no clear spatial structure of the genetic diversity. Populations, where the species co-occurred, tended to display similar levels in genetic diversity for the two species. Demographic inferences supported a postglacial demographic expansion for two A.chilense genetic clusters, one present in the South Island and the eastern coast of the North Island, and the other present in northern South Island. A third genetic cluster located on the western coast of the North Island had a signature of long-term demographic stability. For A.transtasmanicum, the skyline plot also suggested a postglacial demographic expansion. Last, we developed a new molecular tool to quickly and easily distinguish between the two Agarophyton species, which could be used to ease future fine-scale population studies, especially in areas where the two species coexist.

The Biogeographic Importance of Buoyancy in Macroalgae: A Case Study of the Southern Bull-Kelp Genus Durvillaea (Phaeophyceae), Including Descriptions of Two New Species1.

Long-distance dispersal plays a key role in evolution, facilitating allopatric divergence, range expansions, and species movement in response to environmental change. Even species that seem poorly suited to dispersal can sometimes travel long distances, for example via hitchhiking with other, more intrinsically dispersive species. In marine macroalgae, buoyancy can enable adults-and diverse hitchhikers-to drift long distances, but the evolution and role of this trait are poorly understood. The southern bull-kelp genus Durvillaea includes several non-buoyant and buoyant species, including some that have only recently been recognized. In revising the genus, we not only provide updated identification tools and describe two new species (D. incurvata comb. nov. from Chile and D. fenestrata sp. nov. from the Antipodes Islands), but also carry out biogeographic analyses to determine the evolutionary history of buoyancy in the genus. Although the ancestral state was resolved as non-buoyant, the distribution of species suggests that this trait has been both gained and lost, possibly more than once. We conclude that although buoyancy is a trait that can be useful for dispersal (creating evolutionary pressure for its gain), there is also evolutionary pressure for its loss as it restricts species to narrow environmental ranges (i.e., shallow depths).

High diversity of coralline algae in New Zealand revealed: Knowledge gaps and implications for future research.

Coralline algae (Corallinophycideae) are calcifying red algae that are foundation species in euphotic marine habitats globally. In recent years, corallines have received increasing attention due to their vulnerability to global climate change, in particular ocean acidification and warming, and because of the range of ecological functions that coralline algae provide, including provisioning habitat, influencing settlement of invertebrate and other algal species, and stabilising reef structures. Many of the ecological roles corallines perform, as well as their responses to stressors, have been demonstrated to be species-specific. In order to understand the roles and responses of coralline algae, it is essential to be able to reliably distinguish individual species, which are frequently morphologically cryptic. The aim of this study was to document the diversity and distribution of coralline algae in the New Zealand region using DNA based phylogenetic methods, and examine this diversity in a broader global context, discussing the implications and direction for future coralline algal research. Using three independent species delimitation methods, a total of 122 species of coralline algae were identified across the New Zealand region with high diversity found both regionally and also when sampling at small local spatial scales. While high diversity identified using molecular methods mirrors recent global discoveries, what distinguishes the results reported here is the large number of taxa (115) that do not resolve with type material from any genus and/or species. The ability to consistently and accurately distinguish species, and the application of authoritative names, are essential to ensure reproducible science in all areas of research into ecologically important yet vulnerable coralline algae taxa.

Mitochondrial and Plastid Genomes from Coralline Red Algae Provide Insights into the Incongruent Evolutionary Histories of Organelles.

Mitochondria and plastids are generally uniparentally inherited and have a conserved gene content over hundreds of millions of years, which makes them potentially useful phylogenetic markers. Organelle single gene-based trees have long been the basis for elucidating interspecies relationships that inform taxonomy. More recently, high-throughput genome sequencing has enabled the construction of massive organelle genome databases from diverse eukaryotes, and these have been used to infer species relationships in deep evolutionary time. Here, we test the idea that despite their expected utility, conflicting phylogenetic signal may exist in mitochondrial and plastid genomes from the anciently diverged coralline red algae (Rhodophyta). We generated complete organelle genome data from five coralline red algae (Lithothamnion sp., Neogoniolithon spectabile, Renouxia sp., Rhodogorgon sp., and Synarthrophyton chejuensis) for comparative analysis with existing organelle genome data from two other species (Calliarthron tuberculosum and Sporolithon durum). We find strong evidence for incongruent phylogenetic signal from both organelle genomes that may be explained by incomplete lineage sorting that has maintained anciently derived gene copies or other molecular evolutionary processes such as hybridization or gene flow during the evolutionary history of coralline red algae.

Mismatch of morphological and molecular identifications in native and invasive subspecies of Codium fragile (Bryopsidophyceae, Chlorophyta).

Several subspecies are defined within Codium fragile, including the invasive C. fragile ssp. fragile, first reported in New Zealand in 1973. An endemic subspecies, C. fragile ssp. novae-zelandiae, is also found throughout New Zealand. The two subspecies exhibit morphological and molecular variation, although these have never been evaluated together. We compared variation between subspecies at locations in Auckland, identifying subspecies using rps3-rpl16 DNA sequence data, and assessing gross morphological differences, anatomical utricle characters and morphometrics. The taxonomic utility of the morphometric data sets was assessed by linear discriminant analysis. Utricle characters and measurements varied within individual thalli and between different preservation methods. The phenotypes of both subspecies were highly variable and influenced by environment. Accurate subspecies delimitation using morphological data was not possible; the discriminant analyses performed no better than chance for all combinations of the morphological data. Specimens from New Zealand, Canada, Australia and Ireland were sequenced using both the rps3-rpl16 and tufA plastid markers. The tufA elongation factor was shown to be a good candidate for differentiating subspecies of C. fragile. This marker is twice the length of the rps3-rpl16 spacer, shows greater variation between ssp. fragile and novae-zelandiae, and is less prone to sequencing error. A simple restriction enzyme digest of the tufA amplicon can distinguish ssp. fragile and ssp. novae-zelandiae. Our study expands the known range of the ssp. fragile in New Zealand, including the first record of this subspecies from the west coast of Auckland, and points to a need to re-evaluate morphological and molecular criteria for subspecies currently defined within C. fragile.

Highly Conserved Mitochondrial Genomes among Multicellular Red Algae of the Florideophyceae.

Two red algal classes, the Florideophyceae (approximately 7,100 spp.) and Bangiophyceae (approximately 193 spp.), comprise 98% of red algal diversity in marine and freshwater habitats. These two classes form well-supported monophyletic groups in most phylogenetic analyses. Nonetheless, the interordinal relationships remain largely unresolved, in particular in the largest subclass Rhodymeniophycidae that includes 70% of all species. To elucidate red algal phylogenetic relationships and study organelle evolution, we determined the sequence of 11 mitochondrial genomes (mtDNA) from 5 florideophycean subclasses. These mtDNAs were combined with existing data, resulting in a database of 25 florideophytes and 12 bangiophytes (including cyanidiophycean species). A concatenated alignment of mt proteins was used to resolve ordinal relationships in the Rhodymeniophycidae. Red algal mtDNA genome comparisons showed 47 instances of gene rearrangement including 12 that distinguish Bangiophyceae from Hildenbrandiophycidae, and 5 that distinguish Hildenbrandiophycidae from Nemaliophycidae. These organelle data support a rapid radiation and surprisingly high conservation of mtDNA gene syntheny among the morphologically divergent multicellular lineages of Rhodymeniophycidae. In contrast, we find extensive mitochondrial gene rearrangements when comparing Bangiophyceae and Florideophyceae and multiple examples of gene loss among the different red algal lineages.

Complete mitochondrial genome of a rhodolith, Sporolithon durum (Sporolithales, Rhodophyta).

We present the first mitochondrial genome of the nongeniculate coralline red alga, Sporolithon durum (Sporolithales). The genome consists of 45 genes, including 24 protein-coding, 2 rRNA and 19 tRNA genes in a circular molecule of 26,202 bp with overall 28.4% GC content.

Multi-gene phylogenetic analyses of New Zealand coralline algae: Corallinapetra Novaezelandiae gen. et sp. nov. and recognition of the Hapalidiales ord. nov.

Coralline red algae from the New Zealand region were investigated in a study focused on documenting regional diversity. We present a multi-gene analysis using sequence data obtained for four genes (nSSU, psaA, psbA, rbcL) from 68 samples. The study revealed cryptic diversity at both genus and species levels, confirming and providing further evidence of problems with current taxonomic concepts in the Corallinophycidae. In addition, a new genus Corallinapetra novaezelandiae gen. et sp. nov. is erected for material from northern New Zealand. Corallinapetra is excluded from all currently recognized families and orders within the Corallinophycidae and thus represents a previously unrecognized lineage within this subclass. We discuss rank in the Corallinophycidae and propose the order Hapalidiales.

A phylogenetic re-appraisal of the family Liagoraceae sensu lato (Nemaliales, Rhodophyta) based on sequence analyses of two plastid genes and postfertilization development.

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.

Pyropia plicata sp. nov. (Bangiales, Rhodophyta): naming a common intertidal alga from New Zealand.

A commonly found red alga of the upper intertidal zone of New Zealand rocky coasts is described for the first time as Pyropia plicata sp. nov. This species has been incorrectly known as Porphyra columbina Mont. (now Pyropia columbina (Mont.) W.A.Nelson) for many years. Pyropia plicata is widespread and common, and it is readily distinguished from other species of bladed Bangiales in New Zealand by its distinctive morphology, with pleated blades attached by a central rhizoidal holdfast.

Insights from natural history collections: analysing the New Zealand macroalgal flora using herbarium data.

Herbaria and natural history collections (NHC) are critical to the practice of taxonomy and have potential to serve as sources of data for biodiversity and conservation. They are the repositories of vital reference specimens, enabling species to be studied and their distribution in space and time to be documented and analysed, as well as enabling the development of hypotheses about species relationships. The herbarium of the Museum of New Zealand Te Papa Tongarewa (WELT) contains scientifically and historically significant marine macroalgal collections, including type specimens, primarily of New Zealand species, as well as valuable exsiccatae from New Zealand and Australia. The herbarium was initiated in 1865 with the establishment of the Colonial Museum and is the only herbarium in New Zealand where there has been consistent expert taxonomic attention to the macroalgae over the past 50 years. We examined 19,422 records of marine macroalgae from around New Zealand collected over the past 164 years housed in WELT, assessing the records in terms of their spatial and temporal coverage as well as their uniqueness and abundance. The data provided an opportunity to review the state of knowledge of the New Zealand macroalgal flora reflected in the collections at WELT, to examine how knowledge of the macroalgal flora has been built over time in terms of the number of collections and the number of species recognised, and identify where there are gaps in the current collections as far as numbers of specimens per taxon, as well as with respect to geographical and seasonal coverage.

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.