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Coralline red algae in the non-geniculate genera Clathromorphum, Phymatolithon and Lithothamnion are important benthic ecosystem engineers in the photic zone of the Arctic and Subarctic. In these regions, the systematics and biogeography of Clathromorphum and Phymatolithon have mostly been resolved whereas Lithothamnion has not, until now. Seventy-three specific and infraspecific names were given to Arctic and Subarctic Lithothamnion specimens in the late 19th and early 20th century by Frans R. Kjellman and Mikael H. Foslie. DNA sequences from 36 type specimens, five historical specimens, and an extensive sampling of recent collections resulted in the recognition of four Arctic and Subarctic Lithothamnion species, L. glaciale, L. lemoineae, L. soriferum and L. tophiforme. Three genes were sequenced, two plastid-encoded, rbcL and psbA, and the mitochondrial encoded COI-5P; rbcL and COI-5P segregated L. glaciale from L. tophiforme but psbA did not. Partial rbcL sequences obtained from type collections enabled us to correctly apply the earliest available names and to correctly place the remainder in synonymy. We were unable to sequence another 22 type specimens, but all of these are more recent names than those that are now applied. It is difficult to identify these species solely on morpho-anatomy as they can all occur as encrusting corallines or as maerl (rhodoliths). We demonstrate the importance of sequencing historical type specimens by showing that the recently proposed North-east Atlantic L. erinaceum is a synonym of one of the earliest published Arctic species of Lithothamnion, L. soriferum, itself incorrectly placed in synonymy under L. tophiforme based on morpho-anatomy. Based on sequenced specimens, we update the distributions and ecology of these species. [ABSTRACT FROM AUTHOR]

Calcified coralline algae are ecologically important in rocky habitats in the marine photic zone worldwide and there is growing concern that ocean acidification will severely impact them. Laboratory studies of these algae in simulated ocean acidification conditions have revealed wide variability in growth, photosynthesis and calcification responses, making it difficult to assess their future biodiversity, abundance and contribution to ecosystem function. Here, we apply molecular systematic tools to assess the impact of natural gradients in seawater carbonate chemistry on the biodiversity of coralline algae in the Mediterranean and the NW Pacific, link this to their evolutionary history and evaluate their potential future biodiversity and abundance. We found a decrease in the taxonomic diversity of coralline algae with increasing acidification with more than half of the species lost in high pCO2 conditions. Sporolithales is the oldest order (Lower Cretaceous) and diversified when ocean chemistry favoured low Mg calcite deposition; it is less diverse today and was the most sensitive to ocean acidification. Corallinales were also reduced in cover and diversity but several species survived at high pCO2; it is the most recent order of coralline algae and originated when ocean chemistry favoured aragonite and high Mg calcite deposition. The sharp decline in cover and thickness of coralline algal carbonate deposits at high pCO2 highlighted their lower fitness in response to ocean acidification. Reductions in CO2 emissions are needed to limit the risk of losing coralline algal diversity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Adeylithon gen. nov. with one species, A. bosencei sp. nov., belonging to the subfamily Hydrolithoideae is described from Pacific coral reefs based on psbA sequences and morpho‐anatomy. In contrast with Hydrolithon, A. bosencei showed layers of large polygonal "cells," which resulted from extensive lateral fusions of perithallial cells, interspersed among layers of vegetative cells. This anatomical feature is shared with the fossil Aethesolithon, but lacking DNA sequences from the fossils and the fragmentary nature of Aethesolithon type material, we cannot ascertain if Adeylithon and Aethesolithon are congeneric. Morpho‐anatomical features of A. bosencei were generally congruent with diagnostic features of the subfamily Hydrolithoideae: (i) outline of cell filaments entirely lost in large portions due to pervasive and extensive cell fusions, (ii) trichocytes not arranged in tightly packed horizontal fields, (iii) basal layer without palisade cells, and (iv) cells lining the canal pore oriented more or less perpendicular to roof surface and not protruding into the canal. However, it showed a predominant monomerous thallus organization and trichocytes were disposed in large pustulate, horizontal fields, although they were not tightly packed and did not become distinctly buried in the thallus. Only mature tetrasporangial conceptacles were observed, therefore the type of conceptacle roof formation remained undetermined. Adeylithon bosencei occurs on shallow coral reefs, in Australia, Papua New Guinea, and South Pacific islands (Fiji, Vanuatu). Fossil Aethesolithon is considered an important component of shallow coral reefs since the Miocene; fossil records showed a broad Indo‐Pacific distribution, but a long‐term process of range contraction in the last 2.6 million years, resulting in an overlap with the distribution of the extant Adeylithon. While the congeneric nature of extant and fossil taxa remained uncertain, similarities in morpho‐anatomy, habitat, and distribution may indicate that both taxa likely shared a common ancestor. [ABSTRACT FROM AUTHOR]

To address the taxonomic uncertainty of Sporolithon species named in the early to mid-20th century, targeted PCR sequencing was performed on eight historical type specimens and on recently collected specimens. Six type specimens amplified for the rbcL gene and were Sanger sequenced yielding sequences ranging in length from 118 to 280 base pairs (bp). One, S. australasicum, failed to amplify and another, S. howei, was amplified for the psbA gene yielding a sequence 544 bp in length. The 118 bp long rbcL sequence of the lectotype of S. crassiramosum showed that it is a later, heterotypic synonym of S. molle. The rbcL sequences of type specimens of S. episoredion, S. schmidtii, S. sibogae and S. timorense ranged from 118 to 228 bp, and each is a distinct species. The 544 bp long psbA sequence of S. howei is also unique. The 280 bp long rbcL sequence of the lectotype of S. durum did not match any sequence with that name in any public repository, including the previously published complete plastome and mitogenome sequences. However, it was identical in sequence to a specimen in GenBank from the southern coast of Western Australia as well as several other sequences generated from field-collected specimens from the states of South Australia and Western Australia. The rhodolith specimens from New Zealand previously called S. durum are S. nodosum sp. nov. The species is endemic to New Zealand. The epilithic specimens from New Zealand previously called S. durum are S. immotum sp. nov., which is also found along the southeastern coast of Australia. Sporolithon crypticum sp. nov. is described from the southern coast of Western Australia. RAxML and Bayesian phylogenetic analyses of Sporolithon psbA and rbcL sequences are congruent between the two plastid encoded genes. DNA sequencing of type specimens of species of corallines is demonstrated to be the only reliable method to correctly apply names. [ABSTRACT FROM AUTHOR]

DNA sequences obtained from the isolectotype of Jania crassa, collected from Dusky Sound, Fiordland, New Zealand, have revealed the identity of this poorly understood taxon, and enabled comparison with modern material. The name Jania crassa has been previously widely applied in New Zealand and Australia. Data presented here show that Jania crassa differs from other species within the New Zealand region: of the eight species of Jania currently recognized, three are dichotomously branched, and two of these are known from southern New Zealand. Jania crassa can be distinguished from the smaller and epiphytic species of Jania in southern New Zealand, J. sphaeroramosa, on the basis of size and growth habit. Jania crassa appears to be an infrequently collected, possibly endemic species of southern New Zealand, with only one recent collection confirmed. Further collections and sequence data are needed to better understand the distribution of this species, particularly in neighbouring regions. [ABSTRACT FROM AUTHOR]

A constant effort in sequencing an extensive number of specimens originating from comprehensive sampling had return an unprecedented amount of information fostering our understanding of diversity, evolution and distribution of coralline algae; however, many sequences lack reliable assignation of a taxonomic name, specially at the species level. Recently, the sequencing of type material allowed to bridge this gap by providing a direct link between the DNA sequence and the type bearing name. For instance, in the genus Lithophyllum, the identity of three species, generally abundant along the European Atlantic and the Mediterranean, was demonstrated by including sequences of the type material. Nevertheless, for less conspicious species, such as Lithophyllum nitorum, data are still needed to assess distribution, anatomy, phylogenetic affinities and taxonomic status. Using DNA sequences recovered from the type material of L. nitorum, further recent collections were resolved as conspecific and used to improve the description and refine the distribution of this species. Lithophyllum nitorum consisted of subtidal, thin crusts overgrowing fragments of dead maerl, pebbles and drifted fragments of fishing lines. The presence of uniporate conceptacles markedly protruding can be considered an external morphological feature useful to identify L. nitorum from other subtidal Lithophyllum species with similar habitat. Lithophyllum nitorum is reported for the Mediterranean Sea and confirmed in the North East Atlantic, a similar distribution as for L. incrustans and L. hibernicum. [ABSTRACT FROM AUTHOR]

Phymatolithon lusitanicum is a new maerl species described based on an integrative systematic approach including molecular (COI-5P, psbA) and morphological data obtained from recent collections, as well as comparison of type material from the morphologically and ecologically alike NE Atlantic species P. lamii and P. laevigatum. Molecular analyses including type material of P. lamii and P. laevigatum were congruent in delimiting P. lusitanicum as an independent lineage from these crustose species. The three species shared a common external morphology of multiporate asexual conceptacles, but P. lusitanicum has been detected only unattached as maerl while P. lamii and P. laevigatum are crustose. Phymatolithon lusitanicum is particularly abundant in subtidal maerl beds of the Atlantic Iberian Peninsula (Galicia and the Algarve); however it has also been detected northwards in Ireland intertidally and in Western Mediterranean Sea (Alborán Sea, Balearic Islands) down to 64 m. Phymatolithon lusitanicum differs from other Phymatolithon species reported for the European coasts mainly by the external shape of the multiporate asexual conceptacles (pore plate flush with surface or slightly sunken without a conspicuous thick raised rim) and its unattached habit as maerl/rhodolith. In addition, the lectotype of Lithothamnion hamelii turned out to be conspecific to Phymatolithon calcareum, therefore this taxon is proposed as a heterotypic synonym of P. calcareum. Finally, our molecular analyses detected cryptic diversity within the European collections of Phymatolithon, while collections identified as P. lenormandii from Canada or P. repandum from New Zealand were resolved as unrelated to the remaining Phymatolithon. In the light of these results, it is clear that further work is necessary to resolve species diversity within the genus Phymatolithon and its relationship with related genera. [ABSTRACT FROM AUTHOR]

The red algal genus Stenogramma (Gigartinales, Phyllophoraceae) was not recorded in the Indian Ocean. In this study, we used molecular assisted alpha taxonomy to assess the algal diversity of the algal flora of the southern coasts of Madagascar. Using COI-5P sequences as barcode marker and LSU and rbcL sequences to infer phylogenetic relationships, a novel species of Stenogramma has been uncovered at Manantenina, Anosy, Madagascar, which is here described. The species diversity within the genus Stenogramma is discussed and in light of our phylogenetic inference we hypothesized that species of northern and southern hemispheres may have diversified separately. This novel species, being found on subtidal rocks surrounded by sands, the habitat preference of the genus is discussed. [ABSTRACT FROM AUTHOR]

DNA barcodes and morphological observation were used to evaluate the number of species within the genus Corallina sensu lato in Atlantic Iberia and to identify a set of morphological characters that may discriminate them. Five species were detected: (i) C. officinalis, (ii) C. caespitosa, (iii) Ellisolandia elongata, (iv) Corallina sp. 1, and (v) Corallina sp. 2. The first three species were widespread whereas Corallina sp. 1 was only detected in southern Atlantic coasts of Iberia and Corallina sp. 2 occurred both in the Atlantic and the Mediterranean, nevertheless, with morphological and molecular differences. The widespread occurrence of the recently described C. caespitosa along Atlantic Iberia is substantiated with sequence data for the first time; it spans from the Bay of Biscay to Andalusia and the French Mediterranean. Molecular support is also provided for the presence of C. officinalis and E. elongata in Atlantic Iberia. Plants of C. officinalis were correctly identified attending to their external morphology, however two distinct species were detected under the two forms of C. elongata ('typical' and 'elongated') reported for Galicia in the literature ( C. caespitosa and Ellisolandia elongata, respectively). Plant size, habit, branching, and shape of intergenicula seem the most informative morphological characters to discriminate among the various members of Corallina s.l. in Atlantic Iberia. [ABSTRACT FROM AUTHOR]

For the first time, a comprehensive assessment ofMesophyllumspecies diversity and their distribution in Atlantic Europe and the Mediterranean Sea is presented based on molecular (COI-5P,psbA) and morphological data. The distribution ranges were redefined for the four species collected in this study:M. alternans, M. expansum, M. macroblastumandM. sphaericum. Mesophyllum sphaericum,which was previously known only from a single maerl bed in Galicia (NW Spain), is reported from the Mediterranean Sea. The known range ofM. expansum(Mediterranean and Macaronesia) was extended to the Atlantic Iberian Peninsula. The occurrence ofM. alternanswas confirmed along the Atlantic French coast south to Algarve (southern Portugal).Mesophyllum lichenoideswas only recorded from the Atlantic, whereasM. macroblastumappears to be restricted to the Mediterranean Sea. A positive correlation was observed between maximum Sea Surface Temperature (SSTmax) and the depth at whichM. expansumwas collected, suggesting that this species may compensate for higher SST by growing in deeper habitats where the temperature is lower. The latter indicates that geographic shifts in the distribution of coastal species as a result of global warming can possibly be mitigated by changes in the depth profile at which these species occur.Mesophyllum expansum, an important builder of Mediterranean coralligenous habitats, may be a good target species to assess its response to climate change. [ABSTRACT FROM PUBLISHER]

Coralline red algae are important habitat builders in coastal waters around the world but their population genetics has been largely overlooked because of a lack of appropriate markers. Here, next generation sequencing was used to identify the first set of microsatellite loci ever developed for a coralline alga, Phymatolithon calcareum, a common builder of maerl beds, particularly in Europe. Eleven polymorphic microsatellite markers were identified, of which eight were particularly suitable for population and individual-based applications. In these, the number of alleles ranged from two to five, while expected heterozygosities varied from 0.143 to 0.803. Two multiplex polymerase chain reactions were designed and proved to successfully amplify these loci in specimens collected along the European Atlantic. The new set of markers will enable the study of population genetic diversity and connectivity patterns of these non-geniculate corallines that are especially relevant to propose conservation actions. [ABSTRACT FROM AUTHOR]

Fertile gametangial plants of Phymatolithon calcareum, which are seldom reported in the Atlantic European coasts, were collected as encrusting, epilithic plants in a subtidal maerl bed in Brittany (France). Based on their morphological features, the plants were identified as P. calcareum. This identification was further confirmed by DNA barcodes using as a reference COI-5P sequences obtained from the neotype together with recent collections from the Atlantic European maerl beds. The reproductive structures were empty but they were regarded as mature female conceptacles. Compared to the two previous records of gametangial plants of P. calcareum for the Atlantic European waters, the uniporate conceptacles observed in this study are larger, and were collected at a different time of the year. To our knowledge, this is the first time that the occurrence of gametangial plants of P. calcareum is corroborated with molecular tools (DNA barcodes). [ABSTRACT FROM AUTHOR]

In recent years (2007-2009), the distribution and associated flora of maerl beds in southern Portugal (Algarve) were investigated by dredging and SCUBA diving (12-30 m depth). The present work provides the first data on the non-coralline crustose flora associated with maerl beds in Portugal. Peyssonnelia bornetii is a new record for Atlantic European coasts, and new records for Portugal are "Rhododiscus pulcherrimus" (sporophyte phase of Atractophora hypnoides), Contarinia peyssonneliaeformis, "Cruoria rosea" (sporophyte phase of Halarachnion ligulatum), Peyssonnelia armorica, and "Aglaozonia chilosa" (sporophyte phase of Cutleria chilosa). In addition, the records of three other species (Hildenbrandia crouaniorum, Peyssonnelia dubyi, and Peyssonnelia harveyana) completed the distribution gap between the North Iberian Peninsula and the Macaronesian region. The female and carposporangial structures of C. peyssonneliaeformis and P. bornetii are described for the first time. The diversity and species composition observed are compared with previous studies from maerl beds in the northwestern Iberian Peninsula (Galicia) and neighboring areas in the Atlantic Ocean and Mediterranean Sea. In order to facilitate and promote further studies of the crustose flora of subtidal habitats along European coasts, an identification key is provided for the 26 crustose taxa associated with maerl and gravel beds of the Atlantic coast of the Iberian Peninsula. [ABSTRACT FROM AUTHOR]

Mesophyllum sphaericum sp. nov. is described based on spherical maërl individuals (up to 10 cm) collected in a shallow subtidal maërl bed in Galicia (NW Spain). The thalli of these specimens are radially organized, composed of arching tiers of compact medullary filaments. Epithallial cells have flattened to rounded outermost walls, and they occur in a single layer. Subepithallial initials are as long as, or longer than the daughter cells that subtend them. Cell fusions are abundant. Multiporate asexual conceptacles are protruding, mound-like with a flattened pore plate, lacking a peripheral raised rim. Filaments lining the pore canal and the conceptacle roof are composed of five to six cells with straight elongate and narrow cells at their base. Carposporangial conceptacles are uniporate, protruding, and conical. Spermatangial conceptacles were not observed. Molecular results placed M. sphaericum near to M. erubescens, but M. sphaericum is anatomically close to M. canariense. The examination of the holotype and herbarium specimens of M. canariense indicated that both species have pore canal filaments with elongate basal cells, but they differ in number of cells (five to six in M. sphaericum vs. four in M. canariense). Based on the character of pore canal filaments, M. canariense shows similarities with M. erubescens (three to five celled). The outermost walls of epithallial cells of M. canariense are flared compared to the round to flattened ones of M. erubescens, the latter being widely accepted for the genus Mesophyllum. The addition of M. sphaericum as new maërl-forming species suggests that European maërl beds are more biodiverse than previously understood. [ABSTRACT FROM AUTHOR]

We studied crustose seaweeds associated with subtidal maërl beds and gravel bottoms in the Galician rías (NW Iberian Peninsula). Each species is described as well as its habitat and occurrence in maërl beds and gravel bottoms. We confirmed the great crustose species richness associated with European Atlantic maërl beds. We report a new species for the Atlantic Ocean ( Contarinia peyssonneliaeformis) and six new records for the Iberian Peninsula ( Atractophora hypnoides stage “ Rhododiscus pulcherrimus” , Peyssonnelia immersa, Scytosiphon lomentaria stage “ Microspongium gelatinosum” , Petroderma maculiforme, Pseudolithoderma roscoffense and Phycocelis foecunda). Peyssonnelia armorica is a new record for the Atlantic Iberian Peninsula and Peyssonnelia harveyana is a new record for the Galician coast. We provide for the first time observations on spermatangial structures in Cruoria cruoriaeformis occurring on the Atlantic Iberian Peninsula. The Galician crustose algal flora of subtidal maërl beds and gravel bottoms is increased up to 23 species (15 Rhodophyta and 8 Ochrophyta). Peyssonnelia rubra is excluded from the Galician flora. [ABSTRACT FROM AUTHOR]

We studied the conservation status of a maërl bed off Benencia Island (NW Spain) over a 2-year period using SCUBA and dredging. The maërl bed, which includes a maërl beach, extended from the intertidal to subtidal zones (18 m), and occupied an area of 215 ha. It was composed of a pure unattached coralline algal deposit occasionally mixed with broken shells. The area estimated for the highest maërl cover (76–100%) was greater than reported in previous research. The living maërl layer reached 15 cm in depth and the living/dead maërl ratio was high (80–100% living maërl cover). The dominant maërl-forming species was Phymatolithon calcareum, although unattached plants of Mesophyllum sp. reaching 10 cm in diameter were found in two sites. Both maërl species are fruticose. The proportion of discoidal specimens of P. calcareum was related to depth. The associated flora comprised 137 species whose seasonal variations were very marked, with high floristic richness in summer (71 species) and low in winter (35 species). Crustose and turf-like species were the dominant floral components throughout the year, whereas the presence of other species was restricted to specific periods. We propose that Benencia Island be included in future Atlantic Iberian maërl bed conservation schemes. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the IV International Rhodolith Workshop held in Granada, Spain from September 17 to 21, 2012. A total of 51 presentations were made on a variety of research carried out on coralline algae. The workshop provides the international scientific community a unique scenario to be updated and to discuss advances in coralline algae research. Topics discussed include descriptions of new rhodolith beds, ecology and long-term stability of present-day rhodolith beds.

• A time-calibrated phylogeny of the subclass Corallinophycidae is presented. • A comprehensive database of >2000 fossil records were used for the calibration. • Crown group diversification started in the Lower Jurassic and sped up in the Lower Cretaceous. • Families Mastophoraceae, Corallinaceae and Lithophyllaceae are proposed for Corallinales. • Evolutionary trends of vegetative and reproductive features are discussed. The subclass Corallinophycidae is the only group of red algae characterized by the presence of calcite crystals in their cell walls. Except for the Rhodogorgonales, the remaining orders - collectively called corallines - are diverse and widely distributed, having calcified cell walls and highly variable morphology. Corallines constitute the group with the richest fossil record among marine algae. In the present study, we investigate the evolutionary history of the subclass Corallinophycidae and provide a time-calibrated phylogeny to date the radiation of the crown group and its main lineages. We use a multi-locus dataset with an extensive taxon sampling and comprehensive collection of fossil records, carefully assigned to corallines, to reconstruct a time-calibrated phylogeny of this subclass. Our molecular clock analyses suggest that the onset of crown group diversification of Corallinophycidae started in the Lower Jurassic and sped up in the Lower Cretaceous. The divergence time of the oldest order Sporolithales is estimated in the Lower Cretaceous followed by the remaining orders. We discuss the long period of more than 300 million years between the early Paleozoic records attributed to the stem group of Corallinophycidae and the radiation of the crown group. Our inferred phylogeny yields three highly-supported suprageneric lineages for the order Corallinales; we confirm the family Mastophoraceae and amend circumscription of the families Corallinaceae and Lithophyllaceae. These three families are distinguished by a combination of vegetative and reproductive features. In light of the phylogeny, we discuss the evolutionary trends of eleven morphological characters. In addition, we also highlight homoplasious characters and selected autapomorphies emerging in particular taxa. [ABSTRACT FROM AUTHOR]

Background and Aims Kelps are the primary foundation species in temperate subtidal rocky shores worldwide. However, global change is causing their decline with consequences for the organisms that rely on them. An accurate assessment of these consequences may depend on which attributes of the associated community are considered. This study shows that conventional α-diversity approaches may overlook some of these consequences compared to spatially explicit approaches such as with β-diversity. Methods A 1-year seasonal study was conducted to compare the macroalgal understorey between healthy reefs with a Laminaria ochroleuca canopy and degraded reefs where the canopy collapsed years ago due to excessive fish herbivory. At each reef, the understorey seaweed assemblage was recorded in five replicate quadrats to estimate α-diversity (total richness, species density, Shannon index) and β-diversity (intra- and inter-reef scale). Key Results The understorey assemblage exhibited a distinct seasonal dynamic in both healthy and degraded reefs. α-Diversity attributes increased in spring and summer; turf-forming algae were particularly dominant in degraded reefs during summer. β-Diversity also showed seasonal variability, but mostly due to the changes in degraded reefs. None of the α-diversity estimates differed significantly between healthy and degraded reefs. In contrast, spatial β-diversity was significantly lower in degraded reefs. Conclusions Although the loss of the kelp canopy affected the composition of the macroalgal understorey, none of the conventional indicators of α-diversity detected significant differences between healthy and degraded reefs. In contrast, small-scale spatial β-diversity decreased significantly as a result of deforestation, suggesting that the loss of kelp canopy may not significantly affect the number of species but still have an effect on their spatial arrangement. Our results suggest that small-scale β-diversity may be a good proxy for a more comprehensive assessment of the consequences of kelp forest decline. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The analysis of biological and ecological traits has a long history in evolutionary and ecological research. However, trait data are often scattered and standardised terminology that transcends taxonomic and biogeographical context are generally missing. As part of the development of a global trait database of marine species, we collated trait information for European seaweeds and structured the data within the standardised framework of the World Register of Marine Species (WoRMS). We collected 45 175 trait records for 21 biologically and ecologically relevant traits of seaweeds. This resulted in a trait database for 1745 European seaweed species of which more than half (56 %) of the records were documented at the species level, while the remaining 44 % were documented at a higher taxonomic level and subsequently inherited at lower levels. The trait database for European seaweeds will serve as a foundation for future research on diversity and evolution of seaweeds and their responses to global changes. The data will contribute to developing detailed trait-based ecosystem models and will be an important tool to inform marine conservation policies. The data are publicly accessible through the AlgaeTraits portal, 10.14284/574 (AlgaeTraits, 2022). [ABSTRACT FROM AUTHOR]

The temporal dimension of the most recent Corallinaceae (order Corallinales) phylogeny was presented here, based on first occurrence time estimates from the fossil record. Calibration of the molecular clock of the genetic marker SSU entailed a separation of Corallinales from Hapalidiales in the Albian (Early Cretaceous ~105 mya). Neither the calibration nor the fossil record resolved the succession of appearance of the first three emerging subfamilies: Mastophoroideae, Corallinoideae, and Neogoniolithoideae. The development of the tetra/ bisporangial conceptacle roofs by filaments surrounding and interspersed among the sporangial initials was an evolutionary novelty emerging at the Cretaceous--Paleogene boundary (~66 mya). This novelty was shared by the subfamilies Hydrolithoideae, Metagoniolithoideae, and Lithophylloideae, which diverged in the early Paleogene. Subclades within the Metagoniolithoideae and Lithophylloideae diversified in the late Oligocene--middle Miocene (~28-12 mya). The most common reef corallinaceans (Hydrolithon, Porolithon, Harveylithon, "Pneophyllum" conicum, and subclades within Lithophylloideae) appeared in this interval in the Indo-Australian Archipelago. [ABSTRACT FROM AUTHOR]

Rhodolith seabeds are 'ecosystem engineers' composed of free-living calcareous red macroalgae, which create extensive marine habitats. This study addressed how depth influenced the structure (size and morphology) of rhodoliths and the abundance of associated floral and faunal epibionts across the Eastern Atlantic Ocean. Sampling was carried out at two sites within five regions (Brittany, Galicia, Madeira, Gran Canaria, and Principe Island), from temperate to tropical, covering a latitudinal gradient of 47°, in three depth strata (shallow, intermediate and deep), according to the rhodolith bathymetrical range in each region. Depth typically affected the rhodolith size at all regions; the largest nodules were found in the intermediate and deep strata, while rhodolith sphericity was larger at the shallow depth strata. Higher biomasses of attached macroalgae (epiphytes) were observed at depths where rhodoliths were larger. The abundance of epifauna was variable across regions and depth strata. In general, the occurrence, structure, and abundance of the associated biota across rhodolith habitats were affected by depth, with local variability (i.e., sites within regions) often displaying a more significant influence than the regional (large-scale) variation. Overall, this study showed that the rhodolith morphology and associated epibionts (flora and fauna) were mostly affected by depth, irrespective of latitude. [ABSTRACT FROM AUTHOR]

The analysis of biological and ecological traits has a long history in evolutionary and ecological research. However, trait data are often scattered and standardised terminology that transcends taxonomic and biogeographical context are generally missing. As part of the development of a global trait database of marine species, we collated trait information for European seaweeds and structured the data within the standardised framework of the World Register of Marine Species (WoRMS). We collected 45,175 records for 21 biologically and ecologically relevant traits of seaweeds. This resulted in a trait database for 1,745 European seaweed species of which more than half (56%) of the records were documented at the species level, while the remaining 44% was documented at a higher taxonomic level and subsequently inherited at lower levels. The trait database for European seaweeds will serve as a foundation for future research on diversity and evolution of seaweeds, and their responses to global changes. The data will contribute to developing detailed trait-based ecosystem models, and will be an important tool to inform marine conservation policies. The data is publicly accessible through the AlgaeTraits portal, algaetraits.org, doi: https://doi.org/10.14284/574, (AlgaeTraits, 2022). [ABSTRACT FROM AUTHOR]