DIFFERENTIAL LIFE HISTORY PHASE EXPRESSION IN TWO COEXISTING SPECIES OF SCYTOSIPHON (PHAEOPHYCEAE) IN NORTHERN CHILE1

The identity of two phaeophycean taxa that monopolized the middle‐lower rocky intertidal zone of a coastal area chronically exposed to copper mine wastes in northern Chile was unraveled. One of them was preliminarily identified as the gametophytic stage of Scytosiphon lomentaria (Lyngbye) Link. The other, a dark crust, resembled the alternate stage of some Scytosiphon species. Comparative analysis of morphology, life history, and DNA sequences strongly suggests that crusts corresponded to sporophytic S. tenellus Kogame and confirm that erect thalli belonged to S. lomentaria. A clear segregation of erect and crustose thalli was found using internal transcribed spacer region 1 and RUBISCO spacer sequences. Furthermore, whereas crusts always grouped with S. tenellus, erect thalli always grouped with S. lomentaria. Life history studies failed to connect the two entities. First, field‐collected S. tenellus produced progeny that either recycled the crust, which reproduced by unilocular zoidangia, or developed into erect thalli. The latter, unlike typical gametophytic S. lomentaria, developed patchy sori of plurilocular zoidangia. Second, S. lomentaria displayed a direct‐type life cycle, in which progeny from erect individuals only developed into erect thalli and produced only plurilocular zoidangia. This constitutes the first experimental study on Scytosiphon from the Pacific coast of South America and the first report of S. tenellus on this coast. It is also the first report of the crustose stage of Scytosiphon appearing as a perennial and dominant algal species in a temperate rocky intertidal system.     

A taxonomic study of Japanese Scytosiphon (Scytosiphonales, Phaeophyceae), including two new species

Morphological and culture studies were carried out on the genus Scytosiphon (Scytosiphonales, Phaeophyceae) growing in Japan. Morphologies of plurilocular zo-idangia and sporophytic thalli were found to be useful as taxonomic characters. Two types of plurilocular zo-idangial sori were recognized: (i) loosely coherent plurilocular zoidangia without a cuticular layer (loose type); (ii) tightly coherent plurilocular zoidangia with a cuticular layer (coherent type). The sporophytic thallus morphology was different among species in general appearance (tufted or discoid), degree of cohesion of erect filaments, and presence or absence of paraphyses. Two new species are described, Scytosiphon gracilis sp. nov. and Scytosiphon tenellus sp. nov, Scytosiphon gracilis is distinguished from other species by a thin medullary layer, coherent plurilocular zoidangia, no ascocysts associated with plurilocular zoidangia, and Compsonema-like sporophytic thalli. Scytosiphon tenellus is characterized by a thin medullary layer, coherent plurilocular zoidangia, ascocysts among plurilocular zoidangial sori, and Stragularia-like sporophytic thalli. Scytosiphon lo-mentaria (Lyngbye) Link is characterized by a constricted gametophytic thallus, loose plurilocular zoidangia, the presence of ascocysts, and sporophytic thaili identified with Microspongium gelatlnosum Reinke.     

Taxonomic study of Scytosiphon (Phaeophyceae) from temperate coasts of Argentina

Scytosiphon is a common intertidal genus widely distributed on temperate coasts worldwide. Recently, eight species have been delimited with molecular tools. Although S. lomentaria is the only species that predominates in the macroalgal literature of the Southwestern Atlantic Ocean (SwAO), unpublished molecular data obtained for a population study of S. lomentaria revealed hidden species diversity of Scytosiphon among the individuals collected from four localities at the SwAO. The aim of this study was to revise the identity and phylogenetic relationships of Scytosiphon from temperate coasts of the SwAO using DNA data. Thalli were collected from the Argentinean coast between 39° S and 43° S, from which cox1 and rbcL gene sequences were obtained. Phylogenies and haplotype networks were inferred and morphology of gametophytes was studied. Four species were recognized, S. lomentaria, S. promiscuus, S. shibazakiorum, and one species that belongs to a complex of species known as “Scytosiphon Atlantic complex.” This complex was known to occur only in the North Atlantic, however, the results found in this study revealed that it has an extended distribution range that includes the southern hemisphere, where its populations have high genetic diversity and unique haplotypes. The morphological differences among the four species were subtle; denoting that previous Scytosiphon records from the SwAO attributed to the renowned S. lomentaria could represent different species. In addition, sex ratio and genome-wide single nucleotide polymorphisms (SNPs) analyses were done for populations of S. promiscuus presumably introduced to the SwAO, and the results indicated that they included female-dominant parthenogenetic populations, which were probably introduced from Japan.     

MORPHOLOGY AND LIFE HISTORY OF SCYTOSIPHON LOMENTARIA (SCYTOSIPHONACEAE,PHAEOPHYCEAE) FROM THE AZORES1

Morphological and culture studies of Scytosiphon lomentaria (Lyngbye) Link and Microspongium gelatinosum Reinke (Scytosiphonaceae, Phaeophyceae) were undertaken on material collected on the Island of São Miguel, Azores, where both species were commonly found. Erect thalli of S. lomentaria collected in the field were up to 33 cm long and 2.3 mm wide, tubular, hollow, and commonly constricted at intervals. The plurilocular sporangia were positioned in continuous sori on the thallus surface. Ascocysts were present. In the field, M. gelatinosum formed crustose to slightly pulvinate plants, were spongy in texture, and dark brown to black in color, which were circular or irregularly spreading over several centimeters and firmly attached to the substratum. Sessile unilocular sporangia were located in sori on the crust surface. In culture S. lomentaria plurispores developed into Microspongium‐like crustose prostrate thalli that formed unilocular sporangia. Unispores developed into new erect thalli that formed plurilocular sporangia. Sexual reproduction was not observed. In culture, M. gelatinosum unispores developed into erect thalli identical with S. lomentaria. These results are similar to those reported for other areas and suggest the occurrence in the Azorean plants of a monophasic and heteromorphic life history, involving both entities studied.     

Complanate Scytosiphon lomentaria (Lyngbye) J. Agardh (Scytosiphonales: Phaeophyta) from Southern Australia: The effects of season,temperature, and daylength on the life history

Cultures of the complanate form of Scytosiphon lomentaria (Lyngbye) J. Agardh were initiated at different times of year, maintained in several temperature daylength regimes, and grown through at least three generations. The composition of the F₁ generation varied on a seasonal basis, with a greater proportion of complanate individuals in winter and a predominance of ralfsioid and and cylindrical individuals in spring-summer.In culture, complanate thalli were only initiated from zooids derived from thalli (complanate or ralfsioid) grown in short days; ralfsioid progeny developed in long days. Some kinds of ralfsioid thalli and the cylindrical thalli developed and reproduced in long and short day conditions. The effects of temperatures between 11° and 20°C were subtle, and principally related to the rate of growth of cultured plants and not to the determination of particular stages in the life history.The relationship between the seasonal occurrence of complanate S. lomentaria, its seasonal pattern of reproduction, and the effects of daylength on the life history are discussed.     

ANTIOXIDANT RESPONSES IN SCYTOSIPHON LOMENTARIA (PHAEOPHYCEAE) INHABITING COPPER‐ENRICHED COASTAL ENVIRONMENTS1

Scytosiphon lomentaria (Lingb.) Link. (Phaeophyceae) is one of the two dominant seaweeds in a coastal area of northern Chile affected by copper mine wastes, where the concentration of copper in water and algal tissues remains higher than in nonimpacted sites. Copper‐loaded plants develop oxidative stress, as demonstrated by the increased levels of reactive oxygen species and lipoperoxides. This stress was associated with 1) an enhanced activity of the antioxidant enzymes catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase and 2) an inhibition of the glutathione reductase activity. Furthermore, stressed plants showed a decrease in glutathione and phenolic compounds levels and an increase in total ascorbate. Reciprocal transplants revealed that plants rapidly adjusted their antioxidant system in response to the conditions of the receiving site. In individuals transplanted from the copper‐enriched environment to the control site, normal levels of lipoperoxides and antioxidant compounds were restored in 48 h and antioxidant enzymes recovered their basal activities in 96 h. Individuals transplanted from the control site to the copper‐enriched area adjusted their antioxidant compounds and antioxidant enzymes within 48 h and 96 h, respectively, and reached the functional status of the local plants. We conclude that S. lomentaria inhabiting the copper‐enriched area buffered oxidative stress by a simultaneous involvement of antioxidant enzymes and water‐soluble antioxidant compounds. These antioxidant responses were rapid and reversible, suggesting that copper resistance in S. lomentaria is a constitutive trait and that copper enrichment of the area did not result in a locally adapted copper‐tolerant ecotype.     

PYRENOID FORMATION ASSOCIATED WITH THE CELL CYCLE IN THE BROWN ALGA,SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES,PHAEOPHYCEAE)1

Vegetative cells of the brown alga Scytosiphon lomentaria (Lyngbye) Link characteristically have only one chloroplast with a prominent protruding pyrenoid, whereas zygotes have both paternal and maternal chloroplasts. In zygotes, before cell and chloroplast division, each chloroplast has an old and a new pyrenoid. In this study, we raised a polyclonal antibody to RUBISCO and examined the distribution of RUBISCO by immunofluorescence microscopy, focusing on new pyrenoid formation in vegetative cells of gametophytes and zygotes in Scytosiphon. In interphase, only one old pyrenoid was positively indicated by anti‐RUBISCO antibody in vegetative cells of gametophytes. From mid‐S phase, small fluorescence aggregates reflecting RUBISCO localization started to appear at stroma positions other than adjacent to the old protruding pyrenoid. The fluorescent spots eventually coalesced into a protrusion into the adjacent cytoplasm. We also used inhibitors to clarify the relationship between the cell cycle and new pyrenoid formation, using zygotes after fertilization. When DNA replication was blocked by aphidicolin, new pyrenoid formation was also inhibited. Washing out aphidicolin permitted new pyrenoid formation with the progression of the cell cycle. When mitosis was prolonged by nocodazole, which disrupted the spindle microtubules, the fluorescent masses indicating RUBISCO localization continued to increase when compared with pyrenoid formation in untreated zygotes. During treatment with chloramphenicol, mitosis and cytokinesis were completed. However, there was no occurrence of new RUBISCO localization within the chloroplast stroma beyond the old pyrenoid. From these observations, it seems clear that new pyrenoid formation in the brown alga Scytosiphon depends on the cell cycle.     

HETEROMORPHIC LIFE-HISTORY STRATEGIES IN THE BROWN ALGA SCYTOSIPHON LOMENTARIA (LYNGB.) LINK1

The adaptive significance of a life-history strategy, expressed as divergent morphological forms, was examined for the heteromorphic alga Scytosiphon lomentaria. Successional studies were performed by physically clearing mature, temporally-constant intertidal communities on San Clemente I., California. At week six, after clearing, complanate thalli dominated the successional plots (mean cover = 23.5%) and began to decline as the cylindrical form became abundant. The latter attained its peak cover (82.3%) at week 13, whereupon it too began a precipitous reduction. The crustose ralfsioid form appeared surprisingly early (4–13 wks) in trace amounts but did not achieve its greatest cover (85.0%) until week 43. The ranking from high to low primary productivity (cylindrical form = 8.1 mg C · g dry. wt^-1·h^-1, complanate form = 6.5 mg, crustose form = 0.5 mg) corresponded closely with the data for photosynthetic vs. structural components (cylindrical = 92.3% pigmented, complanate = 65.3%, crustose = 32.0%). This finding indicates that selection in the crust form, which is more readily accessible to epilithic grazers, has tended to increase allocation of materials to nonpigmented structural tissue at the expense of photosynthetic tissue and reduced production rates. The results for thallus losses to urchin grazing over 48 h were complanate form = 82.7% lost, cylindrical = 81.4% and crustose = 16.2%, which correlates with the calorific contents of the three forms (i.e. complanate = 4.97 kcal · ash-free g dry wt.^-1, cylindrical = 4.46 kcal and crustose = 3.55 kcal). The crustose form had tougher thalli (26 g · mm^-2 to penetrate thallus) than either the complanate form (12 g) or the cylindrical form (15 g). It is likely that opposing selective factors have resulted in the evolutionary divergences observed in algae with heteromorphic life histories. Previous work may have overemphasized the selective role of grazing because the crustose form is also adapted to withstand physical forces (sand-scouring, burial and wave-shearing) or as an overwintering stage under physiologically stressful conditions.     

Characterization of centrin genes from Ochromonas danica (Chrysophyceae) and Scytosiphon lomentaria (Phaeophyceae)

Centrin, the EF‐hand Ca²⁺‐binding protein is localized at the basal apparatus of flagella and in centrioles in many eukaryotic cells. In the present study, centrin genes of the heterokont algae have been clarified for the first time. We isolated and analyzed cDNA and genomic DNA of centrin genes from the crysophycean alga Ochromonas danica Prings (UTEX LB1298) and the brown alga Scytosiphon lomentaria (Lyngbye) Link. The centrin gene of Ochromonas contained an open reading frame of 163 amino acids. The deduced protein, named Odcen, exhibited 85%, 78% and 59% homology to Chlamydomonas, human and Arabidopsis centrin, respectively. The centrin genes of Scytosiphon contained an open reading frame of 164 amino acids. The deduced protein, named Slcen, exhibited 84%, 77% and 59% homology to Chlamydomonas, human and Arabidopsis centrin, respectively. Both Odcen and Slcen possessed N‐terminal extensions before the conserved amino acid among various centrins, four EF‐hand domains and an aromatic amino acid at the C‐terminus. Southern blot hybridization suggested that the centrin gene occurs as a single copy gene in both Ochromonas and Scytosiphon genomes. Comparison of the sequence of the cDNA and the genomic DNA revealed that the Odcen gene was split into three fragments by introns and Slcen gene consisted of five fragments. The junctions of all introns of both genes conformed to the GT–AG rule. The introns of Slcen gene were considerably long and, as a result, the Slcen gene was approximately seven times longer than Odcen gene.     

EFFECTS OF FIXATIVES ON THE ULTRASTRUCTURE OF PHYSODES IN VEGETATIVE CELLS OF SCYTOSIPHON LOMENTARIA (SCYTOSIPHONACEAE,PHAEOPHYTA)1

The effects of different glutaraldehyde-osmium fixation schedules on the ultrastructure of the vegetative cells from the meristematic regions of Scytosiphon lomentaria (Lyngbye) Link fronds are described. The best overall preservation of cell structure was obtained with a 2 h fixation in 2.5–3.5% glutaraldehyde in 0.1 M cacodylate buffered seawater (pH 7.0), followed after washing by 1 h post fixation in 1% osmium tetroxide. The addition of 1% caffeine to the glutaraldehyde fixative resulted in better retention and spatial localization of the electron dense phenolic deposits within the cells. Particular attention was paid to the effects of the various fixation schedules on the electron-dense material within the cells and the images obtained were compared with previous accounts of brown algal cells. It is proposed that the term physode should be restricted to the discrete electron dense spherical bodies within the vacuoles and not applied to electron dense material in general. Although the organization of Scytosiphon cells was similar to that previously reported in the Scytosiphonaceae, the organization of the plasmodesmata into pit fields is at variance with previous accounts.     

A complex species complex: The controversial role of ecology and biogeography in the evolutionary history of Syllis gracilis Grube, 1840 (Annelida,Syllidae)

The cryptic diversity in the polychaete Syllis gracilis Grube, 1840, in the Mediterranean Sea was examined with an integrative morpho-molecular approach. Individuals of S. gracilis were collected at eleven Mediterranean localities to provide an insight into the role of brackish environments in inducing cryptic speciation. The examination of morphological features combined with a molecular genetic analysis based on a partial sequence of the 16S rRNA gene highlighted discrepancies between morphological and molecular diversity. Morphological data allowed to identify a morphotype with short appendages occurring in coralline algae communities and another one with long appendages observed in brackish-water environments and Sabellaria reefs. Multivariate analyses showed that sampling localities were the greatest source of morphological divergence, suggesting that phenotypic plasticity may play a role in local adaptations of S. gracilis populations. Molecular data showed the occurrence of four divergent lineages not corresponding to morphological clusters. Different species delimitation tests gave conflicting results, retrieving, however, at least four separated entities. Some lineages occurred in sympatry and were equally distributed in marine and brackish-water environments, excluding a biogeographic or ecological explanation of the observed pattern and suggesting instead ancient separation between lineages and secondary contact. The co-occurrence of different lineages hindered the identification of the lineage corresponding to S. gracilis sensu stricto. The discrepancy between morphological and molecular diversity suggests that different environmental and biogeographic features may interact in a complex and unpredictable way in shaping diversity patterns. An integrative approach is needed to provide a satisfactory insight on evolutionary processes in marine invertebrates.     

Intraregional variation among Alexandrium catenella (Dinophyceae) strains from southern Chile: Morphological,toxicological and genetic diversity

Morphological, toxicological and phylogenetic analyses, using the partial LSU gene and internal spacer (ITS) regions of the rDNA gene, were combined to evaluate the intraregional diversity of Alexandrium catenella occurring along the southern coast of Chile. Twenty-two strains isolated from different localities along the wide area of distribution of the species (from 42°S to 55°S) were examined by these three approaches. Morphologically, although the strains showed diagnostic characters according to the species definition, variations in these traits within and between strains were also observed. The absence of an apical or posterior attachment pore, for instance, was observed mainly in old isolates. Indirect connection between the apical and 1′ plates, traits normally seen in other species of the same genus, was also noted in some strains. However, the lack of a ventral pore on the 1′ plate was one of the most distinctive characteristics present in all the Chilean strains. Toxicologically, the Chilean strains were characterized by the dominance of N-sulfocarbamate (C1,2) and gonyautoxins (GTX1–4), but also by the scarcity or absence of saxitoxin. Considering the dominance of these toxins in each strain, at least two distinctive toxin patterns were distinguished. Through rDNA sequence analysis, the Chilean strains were segregated as part of Clade I (North American) of the Alexandrium tamarense species complex. Nevertheless, significant genetic diversity was also observed among the Chilean strains, especially using ITS sequences. Through these three approaches, Chilean strains of A. catenella showed significant intraregional variability, which is appropriate for a native species. However, the distribution of its genetic diversity seems to be inconsistent with the apparent northward expansion observed along the west coast of South America.     

Phylogeny and biogeography of Muusoctopus (Cephalopoda: Enteroctopodidae)

Deep‐sea octopuses of the genus Muusoctopus are thought to have originated in the Pacific Northern Hemisphere and then diversified throughout the Pacific and into the rest of the World Ocean. However, this hypothesis was inferred only from molecular divergence times. Here, the ancestral distribution and dispersal routes are estimated by Bayesian analysis based on a new phylogeny including 38 specimens from the south‐eastern Pacific Ocean. Morphological data and molecular sequences of three mitochondrial genes (16S rRNA, COI and COIII) are presented. The morphological data confirm that specimens newly acquired from off the coast of Chile comprise two species: Muusoctopus longibrachus and the poorly described species, Muusoctopus eicomar. The latter is here redescribed and is clearly distinguished from M. longibrachus and other closely related species in the region. A gene tree was built using Bayesian analysis to infer the phylogenetic position of these species within the species group, revealing that a large genetic distance separates the two sympatric Chilean species. M. longibrachus is confirmed as the sister species of Muusooctopus eureka from the Falkland Islands; while M. eicomar is a sister species of Muusoctopus yaquinae from the North Pacific, most closely related to the amphi‐Atlantic species Muusoctopus januarii. Molecular divergence times and ancestral distribution analyses suggest that genus Muusoctopus may have originated in the North Atlantic: one lineage dispersed directly southward to the Magellan region and another dispersed southward along the Eastern Pacific to the Southern Ocean and Antarctica. The Muusoctopus species in the Southern Hemisphere have different phylogenetic origins and represent independent invasions of this region.     

AN ELECTRON MICROSCOPE STUDY OF GAMETE RELEASE AND SETTLING IN THE COMPLANATE FORM OF SCYTOSIPHON (SCYTOSIPHONACEAE,PHAEOPHYTA)1

This paper describes the ultrastructural characteristics of gametes and their liberation from the gametangia in Scytosiphon sp., a brown alga showing only slight sexual differentiation. Both male and female gametes are released initially into a central cavity which forms in the gametangial sorus by the extensive dissolution of the internal cell walls. Scytosiphon sp. gametes possess structural features in common with the zoids of other species of brown algae. Gamete fine structure is discussed in relation to cell function. After release from the gametangial sorus, female gametes can be distinguished from males by the presence of a large number of Golgi-derived vesicles with electron dense cores. It is possible that these vesicles contain the sex attractant compound. When gametes settle they become spherical, the flagella and eyespot are withdrawn into the cell and adhesive material, apparently originating from the activity of the Golgi body, appears on the surface of the cell.     

Species delimitation of Chinese hop‐hornbeams based on molecular and morphological evidence

Species delimitation through which infers species boundaries is emerging as a major work in modern systematics. Hop‐hornbeam species in Ostrya (Betulaceae) are well known for their hard and heavy woods. Five species were described in China and their interspecific delimitations remain unclear. In this study, we firstly explored their distributions in all recorded field sites distributed in China. We then selected 110 samples from 22 natural populations of five species from this genus and one type specimen of O. yunnanensis, for molecular barcoding analyses. We sequenced four chloroplast (cp) DNA fragments (trnH–psbA, trnL–trnF, rps16, and trnG) and the nuclear internal transcribed spacer (ITS) region for all samples. Sequence variations of Ostrya from four cpDNA fragments identified three groups that showed no correspondence to any morphological delimitation because of the incomplete lineage sorting and/or possible interspecific introgression in the history. However, phylogenetic analyses of ITS sequence variations discerned four species, O. japonica, O. rehderiana, O. trichocarpa, and O. multinervis while O. yunnanensis nested within O. multinervis. Morphological clustering also discerned four species and showed the complete consistency with molecular evidence. Moreover, our phylogenetic analyses‐based ITS sequence variations suggested that O. trichocarpa comprised an isolated lineage different from the other Eurasian ones. Based on these results, hop‐hornbeams in China should be treated as four separate species. Our results further highlight the importance of ITS sequence variations in delimitating and discerning the closely related species in plants.     

Description of a New Freshwater Ciliate Epistylis wuhanensis n. sp. (Ciliophora,Peritrichia) from China,with a Focus on Phylogenetic Relationships within Family Epistylididae

Two populations of Epistylis wuhanensis n. sp., a new freshwater peritrich ciliate, were isolated from different freshwater ponds located in Hubei, China. Their morphological characteristics were investigated using live observation, protargol impregnation, and scanning electron microscopy (SEM). Specimens from the two populations showed identical arrangement of the infraciliature and identical small subunit ribosomal RNA (SSU rRNA) gene and ITS1‐5.8S‐ITS2 sequences. The zooids present bell‐shaped and 90–175 × 27–54 μm in vivo. Macronucleus is variable in shape and located in the middle of cell. Pellicle is usually smooth with 139–154 and 97–105 striations above and below the trochal band, respectively. SSU rRNA gene and ITS1‐5.8S‐ITS2 sequences of E. wuhanensis n. sp. did not match any available sequences in GenBank. Phylogenetically, E. wuhanensis n. sp. clusters with the other Epistylis within the family Epistylididae, but is distinct from the major clades of Epistylis. Above all, the morphological characteristics and molecular analyses support that the present Epistylis is a new species. Expanded phylogenetic analyses of sessilids based on both SSU rRNA gene sequences and ITS1‐5.8S‐ITS2 sequences reveal that the genus Epistylis consists of Epistylis morphospecies and taxonomic revision of the genus is needed.     

Genetic divergence of Chilean long‐tailed snake (Philodryas chamissonis) across latitudes: conservation threats for different lineages

Aim The Chilean long‐tailed snake (Philodryas chamissonis) has a wide distribution across different latitudes and ecosystems in Chile ranging from the south of the Atacama Desert (26° S) to the extremely humid Valdivian temperate rain forest (40° S). Throughout this vast distribution, which is isolated by the Andes mountain range on the east and the Pacific Ocean on the west, there are biogeographical boundaries and large geographical barriers that must have played an important role in the distribution of genetic diversity within this species. This study aimed at elucidating the evolutionary history of P. chamissonis in Chile by analysis of mitochondrial DNA sequences. Location Chile (29°41′–38°23′ S). Methods We extracted DNA from 66 tissue samples collected across different latitudes and amplified and sequenced the mitochondrial DNA control region and the NADH dehydrogenase subunit 4 gene for phylogenetic and population analysis. Results Four distinct haplogroups were identified for P. chamissonis. These are highly consistent with a latitudinal geographic pattern, different ecosystems and the increase in topography towards central Chile. Three of the four haplogroups are concentrated in central Chile (33° S latitude) where the highest herpetofaunal diversity of the country is found. The Maipo River acts as historical geographical barrier for the species influenced by Pleistocene glaciation cycles, leading to a marked phylogeographical boundary. A strong population structure was found for the species (Φ_st = 0.78, P < 0.0001), with a high haplotype diversity (h = 0.97 ± 0.01) and nucleotide diversity (π = 0.0151 ± 0.0077). Main conclusions At least three evolutionarily significant units (ESUs) were designated for the species, and these should be taken into account for conservation plans. Three of the four haplogroups found within P. chamissonis are already threatened because their distribution along central Chile overlaps with most of the largest cities in the country.     

Characterization of Prorocentrum elegans and Prorocentrum levis (Dinophyceae) from the southeastern Bay of Biscay by morphology and molecular phylogeny

Benthic Prorocentrum species can produce toxins that adversely affect animals and human health. They are known to co‐occur with other bloom‐forming, potentially toxic, benthic dinoflagellates of the genera Ostreopsis, Coolia, and Gambierdiscus. In this study, we report on the presence of P. elegans M.Faust and P. levis M.A.Faust, Kibler, Vandersea, P.A. Tester & Litaker from the southeastern Bay of Biscay. Sampling was carried out in the Summer‐Autumn 2010–2012 along the Atlantic coast of the Iberian Peninsula, but these two species were only found in the northeastern part of the Peninsula. Strains were isolated from macroalgae collected from rocky‐shore areas bordering accessible beaches. Morphological traits of isolated strains were analyzed by LM and SEM, whereas molecular analyses were performed using the LSU and internal transcribed spacer (ITS)1‐5.8S‐ITS2 regions of the rDNA. A bioassay with Artemia fransciscana and liquid chromatography–high‐resolution mass spectrometry analyses were used to check the toxicity of the species, whose results were negative. The strains mostly corresponded to their species original morphological characterization, which is supported by the phylogenetic analyses in the case of P. levis, whereas for P. elegans, this is the first known molecular characterization. This is also the second known report of P. elegans.