Assessment of rhodolith-forming species diversity in British Columbia uncovers novel cryptic diversity in the genera Boreolithothamnion and Rhodolithia gen. nov. (Florideophyceae, Rhodophyta) and the occurrence of hybrid rhodoliths.

Rhodolith collections in British Columbia have historically been limited, and published regional species diversity data are poor. The acquisition of recent collections, notably from rhodolith beds in Haida Gwaii, provided an opportunity to assess diversity in these waters. The DNA barcode markers COI-5P, rbcL-3P, and psbA were used to identify unique genetic groups, which were then placed into a phylogenetic context with other coralline algae and subsequently observed anatomically.

First report of articuliths (free-living geniculate corallines, Corallinales, Rhodophyta) in the northern hemisphere revealed during diversity surveys of Haida Gwaii, British Columbia, Canada.

Free-living coralline beds are typically composed of rhodoliths, or unattached non-geniculate coralline algae. In 2017, the first beds comprised primarily of free-living geniculate coralline algae, termed articuliths, were documented in Arraial do Cabo Bay in southeastern Brazil. During routine barcode surveys of the Haida Gwaii, British Columbia, Canada flora, 16 rhodolith-like specimens were collected from a rhodolith bed that DNA sequences assigned to the geniculate taxa Calliarthron tuberculosum and Bossiella sp.

Revisiting the species problem in Northeast Pacific ribbon kelp lineages (genus Alaria): Lessons learned using whole genome data.

The transition from interbreeding populations to species continues to represent difficult terrain for phylogenetic investigations. Genotyping entire genomes holds promise for enhancing insights into the process of speciation and evolutionary relationships among recently speciated taxa. Northeast Pacific ribbon kelp was once recognized as four species before they were folded into Alaria marginata based on DNA barcodes, although several lineages continue to be recognized.

Fluvioralfsia iberica gen. et sp. nov., Fluvioralfsiaceae fam. nov.: The first freshwater member of the Ralfsiales (Phaeophyceae), collected from streams in Spain.

A novel brown alga inhabiting freshwater streams in Spain is described herein as Fluvioralfsia iberica gen. et sp. nov.

A revision of the genus Wrangelia (Wrangeliaceae, Ceramiales) in Bermuda resolves six new species including W. ryancraigii from the mesophotic zone.

Four species of the genus Wrangelia are presently known from the western Atlantic Ocean: W. argus, W. bicuspidata, W.

Of sea, rivers and symbiosis: Diversity, systematics, biogeography and evolution of the deeply diverging florideophycean order Hildenbrandiales (Rhodophyta).

The Hildenbrandiales, a typically saxicolous red algal order, is an early diverging florideophycean group with global significance in marine and freshwater ecosystems across diverse temperature zones. To comprehensively elucidate the diversity, phylogeny, biogeography, and evolution of this order, we conducted a thorough re-examination employing molecular data derived from nearly 700 specimens. Employing a species delimitation method, we identified Evolutionary Species Units (ESUs) within the Hildenbrandiales aiming to enhance our understanding of species diversity and generate the first time-calibrated tree and ancestral area reconstruction for this order.

The Dasya baillouviana and D. cryptica complexes (Delesseriaceae, Rhodophyta) in Bermuda with three additional new species from the archipelago.

Continuing molecular studies of the red algal genus Dasya collected off the coast of Bermuda have revealed two new species in the developing D. cryptica species complex-one from each the euphotic and mesophotic zones, D. orae sp.

Unique biodiversity in Arctic marine forests is shaped by diverse recolonization pathways and far northern glacial refugia.

The Arctic is experiencing a rapid shift toward warmer regimes, calling for a need to understand levels of biodiversity and ecosystem responses to climate cycles. This study presents genetic data for 109 Arctic marine forest species (seaweeds), which revealed contiguous populations extending from the Bering Sea to the northwest Atlantic, with high levels of genetic diversity in the east Canadian Arctic. One-fifth of the species sampled appeared restricted to Arctic waters.

Collections from the mesophytic zone off Bermuda reveal three species of Kallymeniaceae (Gigartinales, Rhodophyta) in genera with transoceanic distributions.

A molecular survey of red algae collected by technical divers and submersibles from 90 m in the mesophotic zone off the coast of Bermuda revealed three species assignable to the Kallymeniaceae. Two of the species are representative of recently described genera centered in the western Pacific in Australia and New Zealand, Austrokallymenia and Psaromenia and the third from the Mediterranean Sea and the eastern Atlantic, Nothokallymenia. A phylogenetic analysis of concatenated mitochondrial (COI-5P) and chloroplast (rbcL) genes, as well as morphological characteristics, revealed that two are shown to be new species with distant closest relatives (N.

Glacial vicariance drives phylogeographic diversification in the amphi-boreal kelp Saccharina latissima.

Glacial vicariance is regarded as one of the most prevalent drivers of phylogeographic structure and speciation among high-latitude organisms, but direct links between ice advances and range fragmentation have been more difficult to establish in marine than in terrestrial systems. Here we investigate the evolution of largely disjunct (and potentially reproductively isolated) phylogeographic lineages within the amphi-boreal kelp Saccharina latissima s. l.

Phylogenetic analyses of transcriptome data resolve familial assignments for genera of the red-algal Acrochaetiales-Palmariales Complex (Nemaliophycidae).

Phylogenetic analyses of transcriptome data for representatives of the red algal Acrochaetiales-Palmariales Complex provided robust support for the assignment of genera to the constituent families. In the Acrochaetiales, the genera Acrochaetium, Grania, and an unnamed genus-level lineage (Acrochaetiac sp._1Aus) were assigned to the Acrochaetiaceae, while Audouinella is placed in a resurrected Audouinellaceae and Rhodochorton and Rhododrewia constitute the resurrected Rhodochortonaceae.

Ottia meiospora (Ottiaceae, Rhodophyta), a new genus and family endophytic within the thallus of Nothocladus (Batrachospermales, Rhodophyta).

A new genus, Ottia, and family, Ottiaceae, are proposed within the Acrochaetiales to accommodate the uniseriate red algal endophyte of batrachspermalean taxa previously named Balbiania meiospora. Prior to this study, Balbiania investiens was transferred to its own family and order (Balbianiales) based on comparative DNA sequence data and a distinctive reproductive morphology. However, the second species described in this genus, B.

PCR fishing for red endophytes in British Columbia Kallymeniaceae (Gigartinales, Florideophyceae) uncovers the species-rich Kallymenicola gen. nov. (Palmariales, Nemaliophycidae).

Unexpected contaminants uncovered during routine COI-5P DNA barcoding of British Columbia Kallymeniaceae indicated the presence of a novel lineage allied to the family Meiodiscaceae, Palmariales. Available rbcL data for species of this family were used to design specific primers to screen for the presence of the meiodiscacean species in 534 kallymeniacean specimens primarily from British Columbia, Canada. Ultimately, 43 positive PCR products representing six diverse genetic groups from nine host species were uncovered; three are described here in the new genus Kallymenicola gen.

Kelp transcriptomes provide robust support for interfamilial relationships and revision of the little known Arthrothamnaceae (Laminariales).

If ever there were "charismatic megaflora" of the sea, the Laminariales (kelp) would undoubtedly meet that designation. From the Northeast Pacific kelp forests to the less diverse, but nonetheless dense, kelp beds ranging from the Arctic to the cold temperate waters of the Southern Hemisphere, kelp provide habitat structure and food for a variety of productive marine systems. Consequently, kelp are well represented in the literature, however, understanding their evolution has proven challenging.

Multigene analyses resolve early diverging lineages in the Rhodymeniophycidae (Florideophyceae, Rhodophyta).

Multigene phylogenetic analyses were directed at resolving the earliest divergences in the red algal subclass Rhodymeniophycidae. The inclusion of key taxa (new to science and/or previously lacking molecular data), additional sequence data (SSU, LSU, EF2, rbcL, COI-5P), and phylogenetic analyses removing the most variable sites (site stripping) have provided resolution for the first time at these deep nodes. The earliest diverging lineage within the subclass was the enigmatic Catenellopsis oligarthra from New Zealand (Catenellopsidaceae), which is here placed in the Catenellopsidales ord.

Application of multigene phylogenetics and site-stripping to resolve intraordinal relationships in the Rhodymeniales (Rhodophyta).

Previous molecular assessments of the red algal order Rhodymeniales have confirmed its monophyly and distinguished the six currently recognized families (viz. Champiaceae, Faucheaceae, Fryeellaceae, Hymenocladiaceae, Lomentariaceae, and Rhodymeniaceae); however, relationships among most of these families have remained unresolved possibly as a result of substitution saturation at deeper phylogenetic nodes. The objective of the current study was to improve rhodymenialean systematics by increasing taxonomic representation and using a more robust multigene dataset of mitochondrial (COB, COI/COI-5P), nuclear (LSU, EF2) and plastid markers (psbA, rbcL).

Endemic or introduced? Phylogeography of Asparagopsis (Florideophyceae) in Australia reveals multiple introductions and a new mitochondrial lineage.

The red seaweed Asparagopsis taxiformis embodies five cryptic mitochondrial lineages (lineage 1-5) introduced worldwide as a consequence of human mediated transport and climate change. We compared globally collected mitochondrial cox2-3 intergenic spacer sequences with sequences produced from multiple Australian locations and South Korea to identify Asparagopsis lineages and to reveal cryptic introductions. We report A.

Etheliaceae fam. nov. (Gigartinales, Rhodophyta), with a clarification of the generitype of Ethelia and the addition of six novel species from warm waters.

Based upon COI-5P, LSU rDNA, and rbcL sequence data and morphological characteristics, six new members of the noncalcified crustose genus of red algae Ethelia are described in a new family, Etheliaceae (Gigartinales), sister to the recently described Ptilocladiopsidaceae. The novel species are described from subtropical to tropical Atlantic and Indo-Pacific Ocean basins; E. mucronata sp.

Reproductive morphology and DNA sequences of the brown alga Platysiphon verticillatus support the new combination Platysiphon glacialis.

Platysiphon verticillatus, a brown alga endemic to the Arctic, was described based on vegetative specimens collected at Inglefield Bay, West Greenland. The species is distinctive in having a lanceolate blade-like thallus terminated by a terete portion, both covered with hair-like assimilatory filaments. Punctaria glacialis was described from Eastern Greenland, and the species differs from other Punctaria species in lacking hairs and plurilocular zoidangia.

Divergence time estimates and the evolution of major lineages in the florideophyte red algae.

The Florideophyceae is the most abundant and taxonomically diverse class of red algae (Rhodophyta). However, many aspects of the systematics and divergence times of the group remain unresolved. Using a seven-gene concatenated dataset (nuclear EF2, LSU and SSU rRNAs, mitochondrial cox1, and plastid rbcL, psaA and psbA genes), we generated a robust phylogeny of red algae to provide an evolutionary timeline for florideophyte diversification.

Population genetic analyses are consistent with the introduction of Ceramium secundatum (Ceramiaceae, Rhodophyta) to Narragansett Bay, Rhode Island, USA.

During ongoing DNA barcode (COI-5P) surveys of the macroalgal flora along the northwest Atlantic coast, we discovered a population of Ceramium secundatum in Narragansett Bay, Rhode Island, USA. This species is regarded as common and widespread in the northeast Atlantic, ranging from Norway to Morocco, but until now has not been reported from the western Atlantic. Several lines of evidence suggest that C.

Multigene phylogeny of the red algal subclass Nemaliophycidae.

The red algae (Rhodophyta) are a lineage of primary endosymbionts whose ancestors represent some of the first photosynthetic eukaryotes on the planet. They primarily inhabit marine ecosystems, with only ∼5% of species found in freshwater systems. The subclass Nemaliophycidae is very diverse in ecological and life history features and therefore a useful model to study these traits, but the phylogenetic relationships among the orders are, for the most part, poorly resolved.

Evidence for the introduction of the Asian red alga Neosiphonia japonica and its introgression with Neosiphonia harveyi (Ceramiales, Rhodophyta) in the Northwest Atlantic.

There is currently conflict in the literature on the taxonomic status of the reportedly cosmopolitan species Neosiphonia harveyi, a common red alga along the coast of Atlantic Canada and New England, USA. Neosiphonia harveyi sensu lato was assessed using three molecular markers: COI-5P, ITS and rbcL. All three markers clearly delimited three genetic species groups within N.

Long distance kelp rafting impacts seaweed biogeography in the Northeast Pacific: the kelp conveyor hypothesis.

Routine DNA barcoding of the Haida Gwaii seaweed flora revealed "endemic species" attributed initially to this region's past as a glacial refugium. However, subsequent barcode records from central California rapidly eroded this list leaving species characterized by disjunct distributions (DD) between California and Haida Gwaii. This observation prompted a more detailed look at species for California and British Columbia and revealed that 33 of 180 DNA-barcoded genetic groups in common between these regions (~18%) predominantly displayed DD between California and northern British Columbia.

The monospecific genus Meredithia (Kallymeniaceae, Gigartinales) is species rich and geographically widespread with species from temperate Atlantic, Pacific, and Indian Oceans.

Using sequences of 5' region of the cytochrome oxidase subunit 1 gene, large subunit rDNA, and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene as genetic markers to elucidate their phylogenetic positions, six unknown species from Western Australia, Tasmania, Lord Howe Is., and Norfolk Is. cluster with Meredithia in the Kallymeniaceae (Gigartinales), and are described as new members of this previously monospecific genus.