New branched Porolithon species (Corallinales, Rhodophyta) from the Great Barrier Reef, Coral Sea, and Lord Howe Island.

Porolithon is one of the most ecologically important genera of tropical and subtropical crustose (non-geniculate) coralline algae growing abundantly along the shallow margins of coral reefs and functioning to cement reef frameworks. Thalli of branched, fruticose Porolithon specimens from the Indo-Pacific Ocean traditionally have been called P. gardineri, while massive, columnar forms have been called P. craspedium. Sequence comparisons of the rbcL gene both from type specimens of P. gardineri and P. craspedium and from field-collected specimens demonstrate that neither species is present in east Australia and instead resolve into four unique genetic lineages. Porolithon howensis sp. nov. forms columnar protuberances and loosely attached margins and occurs predominantly at Lord Howe Island; P. lobulatum sp. nov. has fruticose to clavate forms and free margins that are lobed and occurs in the Coral Sea and on the Great Barrier Reef (GBR); P. parvulum sp. nov. has short (<2 cm), unbranched protuberances and attached margins and is restricted to the central and southern GBR; and P. pinnaculum sp. nov. has a mountain-like, columnar morphology and occurs on oceanic Coral Sea reefs. A rbcL gene sequence of the isotype of P. castellum demonstrates it is a different species from other columnar species. In addition to the diagnostic rbcL and psbA marker sequences, the four new species may be distinguished by a combination of features including thallus growth form, margin shape (attached or unattached), and medullary system (coaxial or plumose). Porolithon species, because of their ecological importance and sensitivity to ocean acidification, need urgent documentation of their taxonomic diversity.

Taxonomic contributions to Hapalidiales (Corallinophycidae, Rhodophyta): Boreolithothamnion gen. nov., Lithothamnion redefined and with three new species and Roseolithon with new combinations.

Phylogenetic analyses of rbcL gene sequences and of concatenated rbcL, psbA, and nuclear SSU rRNA gene sequences resolved the generitype of Lithothamnion, L. muelleri, in a clade with three other southern Australian species, L. kraftii sp. nov., L. saundersii sp. nov., and L. woelkerlingii sp. nov. Cold water boreal species currently classified in Lithothamnion and whose type specimens have been sequenced are transferred to Boreolithothamnion gen. nov., with B. glaciale comb. nov. as the generitype. The other species are B. giganteum comb. nov., B. phymatodeum comb. nov., and B. sonderi comb. nov., whose type specimens are newly sequenced, and B. lemoineae comb. nov., B. soriferum comb. nov., and B. tophiforme comb. nov., whose type specimens were already sequenced. Based on rbcL sequences from the type specimens of Lithothamnion crispatum, L. indicum, and L. superpositum, each is recognized as a distinct species and transferred to the recently described Roseolithon as R. crispatum comb. nov., R. indicum comb. nov., and R. superpositum com. nov., respectively. To correctly assign species to these three genera based only on morpho-anatomy, specimens must have multiporate conceptacles and some epithallial cells with flared walls. The discussion provides examples demonstrating that only with phylogenetic analyses of DNA sequences can the evolution of morpho-anatomical characters of non-geniculate corallines be understood and applied at the correct taxonomic rank. Finally, phylogenetic analyses of DNA sequences support recognition of the Hapalidiales as a distinct order characterized by having multiporate tetra/bisporangial conceptacles, and not as a suborder of Corallinales whose tetra/bisporangial conceptacles are uniporate.

Complete Chloroplast Genome of an Endophytic Ostreobium sp. (Ostreobiaceae) from the U.S. Virgin Islands.

We present the complete chloroplast genome sequence of an endophytic Ostreobium sp. isolated from a 19th-century coralline red algal specimen from St. Croix, U.S. Virgin Islands. The chloroplast genome is 84,848 bp in length, contains 114 genes, and has a high level of gene synteny to other Ostreobiaceae.

Resolving some of the earliest names for Corallina species (Corallinales, Rhodophyta) in the North Pacific by sequencing type specimens and describing the cryptic C. hakodatensis sp. nov. and C. parva sp. nov.

Partial rbcL sequences from type specimens of three of the earliest described Corallina species showed that C. arbuscula (type locality: Unalaska Island, Alaska, USA) and C. pilulifera (type locality: Okhotsk Sea, Russia) are synonymous, with C. pilulifera as the taxonomically accepted name and that C. vancouveriensis (type locality: Botanical Beach, Vancouver Island, Canada) is a distinct species. To identify molecular species limits and clarify descriptions and distributions of C. pilulifera and C. vancouveriensis, we sequenced and analyzed portions of one mitochondrial and two plastid genes from historical and recent collections. The single-gene phylogenetic reconstructions support the recognition of both species as distinct, as well as two additional species, C. hakodatensis sp. nov. and C. parva sp. nov., which are sister to, and often morphologically indistinguishable from C. pilulifera and C. vancouveriensis, respectively. DNA sequence data currently illustrate that C. pilulifera is found in the cold northern Pacific waters from the Okhotsk Sea of Russia to Hokkaido, Japan, eastward across the Aleutian Islands to Knoll Head, Alaska, and as far south as Nanaimo, British Columbia. Corallina vancouveriensis is distributed as far west as Attu Island in the Aleutian Islands to Sitka, Alaska, and southeasterly at numerous sites from British Columbia to the north of Point Conception, California, USA. The cryptic species C. hakodatensis and C. parva occur sympatrically with their sister species but with narrower ranges. The complex phylogenetic relationships shown by the single gene trees recommend Corallina as a model genus to explore coralline algal biogeography, evolution, and patterns of speciation.

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.

Type specimen sequencing, multilocus analyses, and species delimitation methods recognize the cosmopolitan Corallina berteroi and establish the northern Japanese C. yendoi sp. nov. (Corallinaceae, Rhodophyta).

A partial rbcL sequence of the lectotype specimen of Corallina berteroi shows that it is the earliest available name for C. ferreyrae. Multilocus species delimitation analyses (ABGD, SPN, GMYC, bPTP, and BPP) using independent or concatenated COI, psbA, and rbcL sequences recognized one, two, or three species in this complex, but only with weak support for each species hypothesis. Conservatively, we recognize a single worldwide species in this complex of what appears to be multiple, evolving populations. Included in this species, besides C. ferreyrae, are C. caespitosa, the morphologically distinct C. melobesioides, and, based on a partial rbcL sequence of the holotype specimen, C. pinnatifolia. Corallina berteroi, not C. officinalis, is the cosmopolitan temperate species found thus far in the NE Atlantic, Mediterranean Sea, warm temperate NW Atlantic and NE Pacific, cold temperate SW Atlantic (Falkland Islands), cold and warm temperate SE Pacific, NW Pacific and southern Australia. Also proposed is C. yendoi sp. nov. from Hokkaido, Japan, which was recognized as distinct by 10 of the 13 species discrimination analyses, including the multilocus BPP.

DNA sequencing of type material and newly collected specimens reveals two heterotypic synonyms for Harveylithon munitum (Metagoniolithoideae, Corallinales, Rhodophyta) and three new species.

Nongeniculate coralline algae are difficult to identify based solely on morpho-anatomy. To address the systematics of several taxonomically challenging taxa, we analyzed DNA sequences of a short portion (118-296 base pairs) of the 3' end of the rbcL gene from three type specimens. The analyses revealed that Harveylithon munitum (basionym: Lithophyllum munitum), described in 1906 from Cave Cays, Exuma Chain, Bahamas, is conspecific with both Goniolithon accretum and Goniolithon affine, described in 1906 from Sand Key, Florida and in 1907 from Culebra Island, Puerto Rico, respectively. Lithophyllum munitum and G. accretum were described in the same 1906 publication and have equal priority. We have selected the currently accepted and most commonly used name H. munitum to apply to this entity. Comparative analyses of rbcL, psbA, UPA, COI, and LSU sequences from contemporary field-collected specimens revealed that H. munitum currently inhabits mesophotic rhodolith beds in the northwestern Gulf of Mexico, as well as the intertidal zone in the Florida Keys, Honduras, Atlantic Mexico, Caribbean Panama, and Guadeloupe, French West Indies. Species delimitation analyses reveal that the Western Atlantic and Australian H. munitum populations may be separate species. Two new species of Harveylithon from the northwestern Gulf of Mexico and one new species from the southwestern Gulf of Mexico, the Caribbean, and the Red Sea were also identified in the analyses and are described.

DNA Sequencing of Type Material Reveals Pneophyllum marlothii comb. nov. from South Africa and P. discoideum comb. nov. (Chamberlainoideae, Corallinales, Rhodophyta) from Argentina.

A partial rbcL sequence from the type material of Spongites discoideus from southern Argentina showed that it was distinct from rbcL sequences of South African specimens to which that name had been applied based on morpho-anatomy. A partial rbcL sequence from an original syntype specimen, herein designated the lectotype, of Lithophyllum marlothii, type locality Camps Bay, Western Cape Province, South Africa, was identical to rbcL sequences of South African field-collected specimens assigned to S. discoideus. Based on phylogenetic analyses of rbcL and/or psbA sequences, both of these species belong in Pneophyllum and are transferred there as P. discoideum comb. nov. and P. marlothii comb. nov. The two species exhibit a distinct type of development where thick, secondary, monomerous disks are produced from thin, primary, dimerous crusts. Whether this type of development represents an example of convergent evolution or is characteristic of a clade of species within Pneophyllum remains to be resolved.

Genetic analysis of the Linnaean Ulva lactuca (Ulvales, Chlorophyta) holotype and related type specimens reveals name misapplications, unexpected origins, and new synonymies.

Current usage of the name Ulva lactuca, the generitype of Ulva, remains uncertain. Genetic analyses were performed on the U. lactuca Linnaean holotype, the U. fasciata epitype, the U. fenestrata holotype, the U. lobata lectotype, and the U. stipitata lectotype. The U. lactuca holotype is nearly identical in rbcL sequence to the epitype of U. fasciata, a warm temperate to tropical species, rather than the cold temperate species to which the name U. lactuca has generally been applied. We hypothesize that the holotype specimen of U. lactuca came from the Indo-Pacific rather than northern Europe. Our analyses indicate that U. fasciata and U. lobata are heterotypic synonyms of U. lactuca. Ulva fenestrata is the earliest name for northern hemisphere, cold temperate Atlantic and Pacific species, with U. stipitata a junior synonym. DNA sequencing of type specimens provides an unequivocal method for applying names to Ulva species.

Mediterranean Lithophyllum stictiforme (Corallinales, Rhodophyta) is a genetically diverse species complex: implications for species circumscription, biogeography and conservation of coralligenous habitats.

Lithophyllum species in the Mediterranean Sea function as algal bioconstructors, contributing to the formation of biogenic habitats such as coralligenous concretions. In such habitats, thalli of Lithophyllum, consisting of crusts or lamellae with entire or lobed margins, have been variously referred to as either one species, L. stictiforme, or two species, L. stictiforme and L. cabiochiae, in the recent literature. We investigated species diversity and phylogenetic relationships in these algae by sequencing three markers (psbA and rbcL genes, cox2,3 spacer), in conjunction with methods for algorithmic delimitation of species (ABGD and GMYC). Mediterranean subtidal Lithophyllum belong to a well-supported lineage, hereby called the L. stictiforme complex, which also includes two species described from the Atlantic, L. lobatum and L. searlesii. Our results indicate that the L. stictiforme complex consists of at least 13 species. Among the Mediterranean species, some are widely distributed and span most of the western and central Mediterranean, whereas others appear to be restricted to specific localities. These patterns are interpreted as possibly resulting from allopatric speciation events that took place during the Messinian Salinity Crisis and subsequent glacial periods. A partial rbcL sequence from the lectotype of L. stictiforme unambiguously indicates that this name applies to the most common subtidal Lithophyllum in the central Mediterranean. We agree with recent treatments that considered L. cabiochiae and L. stictiforme conspecific. The diversity of Lithophyllum in Mediterranean coralligenous habitats has been substantially underestimated, and future work on these and other Mediterranean corallines should use identifications based on DNA sequences.

Evolutionary reversals in Bossiella (Corallinales, Rhodophyta): first report of a coralline genus with both geniculate and nongeniculate species.

This is the first report of a coralline genus with both geniculate (upright fronds with non-calcified joints) and nongeniculate species that has been verified by DNA sequence data. Two nongeniculate (crustose) species of Bossiella are recognized, B. mayae sp. nov. and B. exarticulata sp. nov. DNA sequencing of the lectotype specimen of Pseudolithophyllum whidbeyense revealed that this name had been misapplied and instead belongs to an undescribed coralline species in the Hapalidiales. Phylogenetic analyses of concatenated DNA sequences (psbA, rbcL, COI-5P) indicate that B. mayae and B. exarticulata represent phenotypic reversals from the geniculate character state back to the nongeniculate character state. Secondary loss of genicula has occurred three times in the subfamily Corallinoideae, once to generate the entirely nongeniculate genus Crusticorallina and twice in the now morphologically heterotypic Bossiella. Since phenotypic reversals have occurred several times during the evolution of coralline algae, we speculate about the putative mechanism and adaptive significance of this phenomenon.

Systematic Revision of Symbiodiniaceae Highlights the Antiquity and Diversity of Coral Endosymbionts.

The advent of molecular data has transformed the science of organizing and studying life on Earth. Genetics-based evidence provides fundamental insights into the diversity, ecology, and origins of many biological systems, including the mutualisms between metazoan hosts and their micro-algal partners. A well-known example is the dinoflagellate endosymbionts ("zooxanthellae") that power the growth of stony corals and coral reef ecosystems. Once assumed to encompass a single panmictic species, genetic evidence has revealed a divergent and rich diversity within the zooxanthella genus Symbiodinium. Despite decades of reporting on the significance of this diversity, the formal systematics of these eukaryotic microbes have not kept pace, and a major revision is long overdue. With the consideration of molecular, morphological, physiological, and ecological data, we propose that evolutionarily divergent Symbiodinium "clades" are equivalent to genera in the family Symbiodiniaceae, and we provide formal descriptions for seven of them. Additionally, we recalibrate the molecular clock for the group and amend the date for the earliest diversification of this family to the middle of the Mesozoic Era (∼160 mya). This timing corresponds with the adaptive radiation of analogs to modern shallow-water stony corals during the Jurassic Period and connects the rise of these symbiotic dinoflagellates with the emergence and evolutionary success of reef-building corals. This improved framework acknowledges the Symbiodiniaceae's long evolutionary history while filling a pronounced taxonomic gap. Its adoption will facilitate scientific dialog and future research on the physiology, ecology, and evolution of these important micro-algae.

Genomics reveals abundant speciation in the coral reef building alga Porolithon onkodes (Corallinales, Rhodophyta).

An essential suite of coral reef ecosystem engineers is coralline red algae. Among these, the smooth, encrusting Porolithon onkodes has historically been considered the most important and common reef building species worldwide. We assess P. onkodes biodiversity by performing a genomic analysis of the lectotype specimen collected in 1892 from the Tami Islands, Gulf of Huon, east of New Guinea. Comparisons of DNA sequences from the lectotype specimen to those deposited in GenBank and to newly generated sequences from both field-collected and historical specimens demonstrate that at least 20 distinct species are passing under P. onkodes. We hypothesize that there were multiple evolutionary drivers including ecophysiology, hydrodynamic regimes, and biotic interactions as well as historical biogeography, which resulted in this high diversity of smooth, encrusting Porolithon species throughout the tropics. Our results emphasize the need to document the biodiversity, ecophysiology, and habitats of these tropical, reef-building algae in light of climate change and ocean acidification.

Mitogenome analysis of a green tide forming Ulva from California, USA confirms its identity as Ulva expansa (Ulvaceae, Chlorophyta).

An unknown species of marine sea lettuce was observed forming green tides consecutive years from 2014 to 2016 in Seaside, California. This Ulva sp. was similar in thallus size and shape to U. expansa. To confirm this identification, whole genome sequencing was performed on the bloom-forming species of Ulva and the holotype specimen of U. expansa. The complete green tide Ulva mitogenome is 64,143 bp in length, contains 65 genes, and displays high gene synteny with U. pertusa Kjellman. The mitogenome was incomplete for the holotype of U. expansa, but the analysis yielded the mitoexome, plastid, and nuclear genetic markers. These data verify that the native U. expansa is responsible for the blooms in central California.

Calcifying algae maintain settlement cues to larval abalone following algal exposure to extreme ocean acidification.

Ocean acidification (OA) increasingly threatens marine systems, and is especially harmful to calcifying organisms. One important question is whether OA will alter species interactions. Crustose coralline algae (CCA) provide space and chemical cues for larval settlement. CCA have shown strongly negative responses to OA in previous studies, including disruption of settlement cues to corals. In California, CCA provide cues for seven species of harvested, threatened, and endangered abalone. We exposed four common CCA genera and a crustose calcifying red algae, Peyssonnelia (collectively CCRA) from California to three pCO2 levels ranging from 419-2,013 µatm for four months. We then evaluated abalone (Haliotis rufescens) settlement under ambient conditions among the CCRA and non-algal controls that had been previously exposed to the pCO2 treatments. Abalone settlement and metamorphosis increased from 11% in the absence of CCRA to 45-69% when CCRA were present, with minor variation among CCRA genera. Though all CCRA genera reduced growth during exposure to increased pCO2, abalone settlement was unaffected by prior CCRA exposure to increased pCO2. Thus, we find no impacts of OA exposure history on CCRA provision of settlement cues. Additionally, there appears to be functional redundancy in genera of CCRA providing cues to abalone, which may further buffer OA effects.

The coralline genera Sporolithon and Heydrichia (Sporolithales, Rhodophyta) clarified by sequencing type material of their generitypes and other species.

Interspecific systematics in the red algal order Sporolithales remains problematic. To re-evaluate its species, DNA analyses were performed on historical type material and recently collected specimens assigned to the two genera Sporolithon and Heydrichia. Partial rbcL sequences from the lectotype specimens of Sporolithon ptychoides (the generitype species) and Sporolithon molle, both from El Tor, Egypt, are exact matches to field-collected topotype specimens. Sporolithon crassum and Sporolithon erythraeum also have the same type locality; material of the former appears to no longer exist, and we were unable to PCR amplify DNA from the latter. A new species, Sporolithon eltorensis, is described from the same type locality. We have not found any morpho-anatomical characters that distinguish these three species. No sequenced specimens reported as S. ptychoides from other parts of the world represent this species, and likely reports of S. ptychoides and S. molle based on morpho-anatomy are incorrect. A partial rbcL sequence from the holotype of Sporolithon dimotum indicates it is not a synonym of S. ptychoides, and data from the holotype of S. episporum confirm its specific recognition. DNA sequences from topotype material of Heydrichia woelkerlingii, the generitype species, and isotype material of Heydrichia cerasina confirm that these are distinct species; the taxon reported to be H. woelkerlingii from New Zealand is likely an undescribed species. Type specimens of all other Sporolithon and Heydrichia species need to be sequenced to confirm that they are distinct species; morpho-anatomical studies have proved inadequate for this task.

The complete mitogenome of the rockweed Fucus distichus (Fucaceae, Phaeophyceae).

The rockweed F. distichus is a one of the most common intertidal seaweeds in the northern hemisphere. The systematics of F. distichus however remains open to discussion. Here, we contribute to the bioinformatics and systematics of F. distichus by deciphering its complete mitogenome. The F. distichus mitogenome is 36,400 bp in length, contains 67 genes, and has a gene content, organization, and sequence that are similar to the generitype, F. vesiculusus. These data support the continued recognition of F. distichus as a polymorphic entity with a broad distribution and high degree of ecological diversity.

Analysis of the complete plastomes of three species of Membranoptera (Ceramiales, Rhodophyta) from Pacific North America.

Next generation sequence data were generated and used to assemble the complete plastomes of the holotype of Membranoptera weeksiae, the neotype (designated here) of M. tenuis, and a specimen examined by Kylin in making the new combination M. platyphylla. The three plastomes were similar in gene content and length and showed high gene synteny to Calliarthron, Grateloupia, Sporolithon, and Vertebrata. Sequence variation in the plastome coding regions were 0.89% between M. weeksiae and M. tenuis, 5.14% between M. weeksiae and M. platyphylla, and 5.18% between M. tenuis and M. platyphylla. We were unable to decipher the complete mitogenomes of the three species due to low coverage and structural problems; however, we assembled and analyzed, the cytochrome oxidase I, II, and III loci and found that M. weeksiae and M. tenuis differed in sequence by 1.3%, M. weeksiae and M. platyphylla by 8.4%, and M. tenuis and M. platyphylla by 8.1%. Evaluation of standard marker genes indicated that sequences from the rbcL, RuBisCO spacer, and CO1 genes closely approximated the pair-wise genetic distances observed between the plastomes of the three species of Membranoptera. A phylogenetic tree based on rbcL sequences showed that M. tenuis and M. weeksiae were sister taxa. Short rbcL sequences were obtained from type specimens of M. dimorpha, M. multiramosa, and M. edentata and confirmed their conspecificity with M. platyphylla. The data support the recognition of three species of Membranoptera occurring south of Alaska: M. platyphylla, M. tenuis, and M. weeksiae.

Crusticorallina gen. nov., a nongeniculate genus in the subfamily Corallinoideae (Corallinales, Rhodophyta).

Molecular phylogenetic analyses of 18S rDNA (SSU) gene sequences confirm the placement of Crusticorallina gen. nov. in Corallinoideae, the first nongeniculate genus in an otherwise geniculate subfamily. Crusticorallina is distinguished from all other coralline genera by the following suite of morpho-anatomical characters: (i) sunken, uniporate gametangial and bi/tetrasporangial conceptacles, (ii) cells linked by cell fusions, not secondary pit connections, (iii) an epithallus of 1 or 2 cell layers, (iv) a hypothallus that occupies 50% or more of the total thallus thickness, (v) elongate meristematic cells, and (vi) trichocytes absent. Four species are recognized based on rbcL, psbA and COI-5P sequences, C. painei sp. nov., the generitype, C. adhaerens sp. nov., C. nootkana sp. nov. and C. muricata comb. nov., previously known as Pseudolithophyllum muricatum. Type material of Lithophyllum muricatum, basionym of C. muricata, in TRH comprises at least two taxa, and therefore we accept the previously designated lectotype specimen in UC that we sequenced to confirm its identity. Crusticorallina species are very difficult to distinguish using morpho-anatomical and/or habitat characters, although at specific sites, some species may be distinguished by a combination of morpho-anatomy, habitat and biogeography. The Northeast Pacific now boasts six coralline endemic genera, far more than any other region of the world.

Resolving cryptic species of Bossiella (Corallinales, Rhodophyta) using contemporary and historical DNA.

PREMISE OF THE STUDY: Phenotypic plasticity and convergent evolution have long complicated traditional morphological taxonomy. Fortunately, DNA sequences provide an additional basis for comparison, independent of morphology. Most importantly, by obtaining DNA sequences from historical type specimens, we are now able to unequivocally match species names to genetic groups, often with surprising results. METHODS: We used an integrative taxonomic approach to identify and describe Northeast Pacific pinnately branched species in the red algal coralline genus Bossiella, for which traditional taxonomy recognized only one species, the generitype, Bossiella plumosa. We analyzed DNA sequences from historical type specimens and modern topotype specimens to assign species names and to identify genetic groups that were different and that required new names. Our molecular taxonomic assessment was followed by a detailed morphometric analysis of each species. KEY RESULTS: Our study of B. plumosa revealed seven pinnately branched Bossiella species. Three species, B. frondescens, B. frondifera, and B. plumosa, were assigned names based on sequences from type specimens. The remaining four species, B. hakaiensis, B. manzae, B. reptans, and B. montereyensis, were described as new to science. In most cases, there was significant overlap of morphological characteristics among species. CONCLUSIONS: This study underscores the pitfalls of relying upon morpho-anatomy alone to distinguish species and highlights our likely underestimation of species worldwide. Our integrative taxonomic approach can serve as a model for resolving the taxonomy of other plant and algal genera.