The anatomy of Neotenophycus ichthyosteus gen. et sp. nov. (Rhodomelaceae,Ceramiales), a bizarre red algal parasite from the central Pacific

A minute parasite of Neosiphonia poko (Hollenberg) Abbott from a shallow lagoon on the central-Pacific Johnston Atoll is described as Neotenophycus ichthyosteus Kraft et Abbott, gen. et sp. nov. The infective parasite cell first connects to a central-axial cell of the host, then emerges from between host pericentral cells at a node before dividing into a three- or four-celled primary axis. Epibasal cells of the parasite divide to form three pericentral cells whose derivatives produce a globular head on the basal cell and on which reproductive structures differentiate almost immediately. Trichoblasts on any life-history stage are completely lacking. Spermatangia are borne on mother cells across the whole thallus surface. Procarps consist of four pericentral cells that encircle a subapical fertile-axial cell in an ampullar configuration, one of the pericentral cells serving as the supporting cell and bearing a four-celled carpogonial branch and a single sterile cell. Diploidization results in a longitudinal/concave division of the auxiliary cell and formation of an arching linear series of inner gonimoblast cells, each dividing toward the thallus surface into gonimoblast filaments of very narrow, horizontally aligned cells terminated by initially monopodial, later by sympodial, carposporangia, the whole of the mature female gametophyte consisting of an amalgam of several cystocarps within a lax jacket of sterile gametophytic tissue. Tetrasporophytes are composed of lobes of pericentral-cell-derived filaments, each axial cell of which is ringed by three pericentral cells producing tetrahedral tetrasporangia enclosed by two pre-sporangial cover cells. Affinities of the new genus are discussed and comparison is made particularly to the enigmatic parasite Episporium centroceratis Möbius. It is concluded that relationships with any previously described tribe are so remote or obscure that the new tribe Neotenophyceae should be proposed for it.     

Contrasting patterns of population structure and demographic history in cryptic species of Bostrychia intricata (Rhodomelaceae,Rhodophyta) from New Zealand

Spatial patterns of genetic diversity provide insight into the demography and history of species. Morphologically similar but genetically distinct “cryptic” species are increasingly being recognized in marine organisms through molecular analyses. Such species are, on closer inspection, often discovered to display contrasting life histories or occasionally minor morphological differences; molecular tools can thus be useful indicators of diversity. Bostrychia intricata, a marine red alga, is widely distributed throughout the Southern Hemisphere and comprises many cryptic species. We used mitochondrial cytochrome c oxidase I gene sequences to assess the genetic variation, population genetic structure, and demographic history of B. intricata in New Zealand. Our results supported the existence of three cryptic species of B. intricata (N2, N4, and N5) in New Zealand. Cryptic species N4, which was found throughout New Zealand, showed a higher genetic diversity and wider distribution than the other two species, which were only found in the North Island and northern South Island. Our analyses showed low to moderate genetic differentiation among eastern North Island populations for cryptic species N2, but high differentiation among North and South Island populations for N4, suggesting different population structure between these cryptic species. Data also indicated that N2 has recently undergone population expansion, probably since the Last Glacial Maximum (LGM), while the higher genetic diversity in N4 populations suggests persistence in situ through the LGM. The contrasting population structures and inferred demographic histories of these species highlight that life history can vary greatly even among morphologically indistinguishable taxa.     

Chemical races in the red alga Laurencia nipponica (Rhodomelaceae, Ceramiales)

Genetic variation in the synthesis of halogenated secondary metabolites in the Japanese marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) has been investigated in laboratory crossing experiments and chemical analyses, F₁ tetrasporophytes and F₁ gametophytes resulting from crosses within chemical races produced major metabolites characteristic of these races. F₁ tetrasporophytes derived from reciprocal interracial crosses produced: (i) both parental types of secondary metabolites; (ii) either of the parental types; or (iii) a further major compound in addition to both parental types or in addition to either of the parental types. The latter cases suggest that hybrid-specific products were formed by the combined enzymatic complements of the parents, as F₁ gametophytes derived from these interracial F₁ tetrasporophytes yielded one or other of their parental products in an approximate 1:1 ratio. The population structure was analyzed at localities in Hokkaido, where two of the chemical races occur sympatrically. At Usujiri (Minami-kayabe), where the prepacifenol race and the laureatin race were sym-patric, hybrid gametophytes (recombination type) were found in high frequency in addition to hybrid tetra sporophytes, which strongly suggests that a new, pre-pacifenol/laureatm race is beginning to be produced by natural hybridization and recombination. By contrast, at Oshoro Bay, where the laurencin race and the epi-lauraliene race grew together, the interracial hybrids were rare: only a few tetrasporophytes (probably F₁ generation) were found, suggesting that racial integrity may be retained by habitat segregation and/or the absence of recombination-type gametophytes.     

Echinophycus minutus (Rhodomelaceae, Ceramiales), a new red algal genus and species from north-western Australia

Echinophycus minutus gen. et sp. nov. (Ceramiales, Rhodophyta) is described for specimens collected from a deep‐water habitat in the Dampier Archipelago, northwestern Australia. Plants were dredged from a coarse sand/rubble habitat, where they were partially decumbent and attached to the substratum by numerous unicellular rhizoids, Thalli are to 25 mm in height, uniaxial, with four pericentral cells and a persistent pigmented trichoblast arising on each axial cell. Tricho‐blasts are arranged in a spiral pattern, with a 90° divergence between successive segments. Each trichoblast is composed of a basal cell bearing a cluster of unbranched filaments. Tetrasporangia are tetrahedral and formed in series in normal branches. Procarps have two sterile cell groups. Spermatangia are formed In heads that are terminal on trichoblasts. The new genus is placed in the tribe Brongniartelleae of the family Rhodomelaceae, differing from all other included genera in the morphology of the trichoblasts.     

Neorhodomela enomotoi sp. nov. (Ceramiales, Rhodophyta) from Japan

The red alga Neorhodomela enomotoi Masuda et Kogame (Rhodomelaceae, Ceramiales) is described as a new species from Japan. It is characterized by the following combination of features: (i) thalli reddish-brown and slightly rigid; (ii) first-order branches mostly indeterminately branched; (iii) adventitious branches infrequent, determinately branched and formed chiefly in the axils of lateral branches; (iv) vegetative trichoblasts abundant; (v) tetrasporangia produced on paniculate ultimate and penultimate branches; and (vi) cystocarps flask-shaped (urceolate). This species has been found growing only in the upper subtidal zone in the warm temperate waters of Japan.     

Ultrastructure of trichoblasts in the red alga Osmundea spectabilis var. spectabilis (Rhodomelaceae,Ceramiales)

The apex of the tetrasporangial branches of Osmundea spectabilis var. spectabilis (= Laurencia spectabilis var. spectabilis) exhibits cavities in which tufts of multicellular trichoblasts occur. Trichoblast development in Osmundea spectabilis var. spectabilis begins with the differentiation of an epidermal cell within the crypt. This cell differentiates into a trichoblast mother cell (TMC). The TMC divides to form a two-celled incipient trichoblast. Successive periclinal divisions of the apical cell of the young trichoblast result in the formation of a multicellular developing trichoblast. With the exception of the apical cell all trichoblast cells are at the same developmental stage. They possess a large nucleus, abundant plastids with peripheral and some internal thylakoids and dictyosomes. Daughter chloroplasts result from one constriction or multiple fission of a single chloroplast. Dictyosomal cisternae and mucilage sacs contribute material to wall formation. Each differentiating trichoblast cell is surrounded by a bi-layered wall. The outer wall layer represents the trichoblast mother cell wall and the inner wall layer is the trichoblast cell wall. Mature trichoblast cells have thin walls, probably as a consequence of mucilage extrusion, the most likely function of trichoblasts in Osmundea.     

Dasya adela sp. nov. (Rhodophyta,Ceramiales), an enigmatic new Dasya from a landlocked fjord in southwest Norway

We here report a new Dasya species found in a landlocked fjord or poll in southwestern Norway; Dasya adela sp. nov. The thallus of this species is small (1–3 cm), normally sparsely branched, and its axes are completely covered with cortex cells. The species is set with long (3–4 mm) and flaccid monosiphonous pseudolaterals, and during autumn it showed high growth of adventitious monosiphonous branches. Only a few individuals with tetrasporangia have been recorded, and no sexual reproductive structures have been observed in field collections. In culture stichidia readily developed on the pseudolaterals, with four tetrasporangia per section. The spores showed high mortality. A few sporelings survived in culture, and developed into small and loosely organized filaments with no upright axes. After 2 years in culture a few plants bearing spermatangial branches were observed, but no individuals with carpogonia. The monosiphonous branches are readily shed in culture, attach themselves by rhizoids and rapidly develop into new thalli, some of which have produced tetrasporangial stichidia. Sequences analyses of partial COI and the rbc L gene showed that the new taxon belongs within Dasyoideae. However, no close relationship was found with other European species of Dasya. The new taxon was compared to other Dasya taxa with which it shared a number of selected characters, but none of these taxa shared all characters of the new Dasya.     

Molecular diversity of Amansieae (Ceramiales,Rhodophyta) from the Hawaiian Islands: a multi‐marker assessment reveals high diversity within Amansia glomerata

Sixty‐one Hawaiian algal specimens corresponding to members of the tribe Amansieae (Amansia and Osmundaria) were compared through DNA sequence analysis. Short DNA barcode‐like sequences of mitochondrial cytochrome c oxidase subunit I (COI) and universal plastid amplicon (UPA) markers were obtained for as many of the specimens as possible, and a subset of specimens was also used for amplification and sequencing of the nuclear small‐subunit rRNA (SSU) gene for phylogenetic inference in a broader taxonomic context. Statistical parsimony analysis of the COI and UPA markers for A. glomerata produced relationships among the samples that were largely congruent with each other, although the UPA marker was more conserved. The COI marker yielded three lineages, and nucleotide divergences for these three lineages were intermediate to those typically reported for intraspecific and interspecific comparisons, suggesting that they represent either incipient species or a complex of closely related species. The COI and UPA sequences demonstrated little to no divergence for Osmundaria obtusiloba and the taxon referred to as Amansia fimbrifolia. In contrast, specimens identified as A. daemelii were identical in sequence to lineage 3 sequences of A. glomerata, and it is recommended that this taxon no longer be included in species lists for the Hawaiian flora. Phylogenetic reconstruction based on the SSU gene was largely unresolved, indicating that this marker may be of limited utility for this purpose in this group of algae, but a small amount of nucleotide variation was found for samples of A. glomerata.     

A preliminary molecular phylogeny for New Zealand sheet-web spiders (Cambridgea) and comparison of web-building behaviour

ABSTRACT

Spider webs vary in size to meet the nutritional requirements of the resident spider with the resident’s body size strongly informing these requirements. In this way, the effect of body size on web-building behaviour should be apparent across species. To determine whether the size of analogous web structures scales with body size across closely related species, we first measured mainsheet area and adult female body size of 12 sheet-web spider species (Cambridgea). Using these species, we then generated alignments from the cytochrome c oxidase subunit I (COI) and histone 3 (H3) gene regions. These alignments were phylogenetically analysed using Bayesian inference and maximum likelihood methods. While phylogenetic trees for the COI gene suggested that Cambridgea is monophyletic relative to sampled outgroups, H3 did not. Combining our COI phylogenetic tree’s branch lengths with data on web-building behaviour, we used phylogenetic least squares to determine whether web size scales with spider size across species. While we found evidence that larger species generally build larger webs, the variation in web size across even similarly sized species suggests that environmental characteristics which influence site selection and prey type may play a role in determining the optimal web size for different species.     

A molecular assessment of species diversity and generic boundaries in the red algal tribes Polysiphonieae and Streblocladieae (Rhodomelaceae,Rhodophyta) in Canada

Sequence data generated during a Canadian barcode survey (COI-5P) of the tribes Polysiphonieae and Streblocladieae, a large and taxonomically challenging group of red algae, revealed significant taxonomic confusion and hidden species diversity. Polysiphonia pacifica Hollenberg, P. paniculata Montagne, P. stricta (Dillwyn) Greville and Vertebrata fucoides (Hudson) Kuntze were all complexes of two or more genetically distinct yet overlooked species. One variety of P. pacifica was elevated to the rank of species as P. determinata (Hollenberg) Savoie & Saunders, stat. nov. Several new additions to the Canadian flora were recorded including P. kapraunii Stuercke & Freshwater and P. morrowii Harvey. Subsequent multi-gene (COI-5P, LSU and rbcL) phylogenetic analyses confirmed that the genus Polysiphonia Greville was polyphyletic, and currently assigned species resolved with many other genera. Polysiphonia sensu stricto was restricted to a group of species that formed a monophyletic lineage with the type, Polysiphonia stricta. Carradoriella P.C.Silva was resurrected based on the South African species Carradoriella virgata (C.Agardh) P.C.Silva. Species previously attributed to Polysiphonia were transferred to Carradoriella, Leptosiphonia and Vertebrata as well as to three new genera described here: Acanthosiphonia gen. nov., based on A. echinata (Harvey) comb. nov.; Eutrichosiphonia gen. nov. for E. confusa (Hollenberg) comb. nov. and E. sabulosia (B.Kim & M.S.Kim) comb. nov.; and Kapraunia gen. nov., which includes K. schneideri (Stuercke & Freshwater) comb. nov. and three additional species.     

PCR gut analysis reveals that Tenuiphantes tenuis (Araneae: Linyphiidae) is a potentially significant predator of Argentine stem weevil,Listronotus bonariensis (Coleoptera: Curculionidae), in New Zealand pastures

Polymerase chain reaction (PCR) gut analysis was conducted on specimens of the introduced spider Tenuiphantes tenuis collected from dairy pasture in Canterbury, New Zealand. PCR primers were specifically designed to amplify a fragment of the mitochondrial gene cytochrome c oxidase subunit 1 (COI) from Listronotus bonariensis and revealed that this major pasture pest species is consumed in the field by T. tenuis. The field predation rate of L. bonariensis by T. tenuis was estimated from our PCR results together with published data on the degradation of DNA and the density of T. tenuis in Canterbury pastures. We found that T. tenuis is a potentially significant predator of L. bonariensis in New Zealand pastures.     

Ultrastructure of the early stages of carposporophyte development in the red algaChondria tenuissima (Rhodomelaceae,Ceramiales)

The ultrastructure of the early stages of carposporophyte development in the marine red algaChondria tenuissima has been studied. The diploid carposporophyte grows on the gametophyte. Apical gonimoblast cells develop into diploid carpospores. The basal gonimoblast cells cease to divide and undergo considerable cytoplasmic changes before they become incorporated into the expanding fusion cell. Nucleus and plastids degenerate gradually, while mitochondria remain intact. The smooth endoplasmic reticulum becomes prominent, it seems to produce small vesicles with electron dense contents. Simultaneously, numerous mucilage sacs are formed, presumably from dilating ER cisternae. The contents of the mucilage sacs are secreted by exocytosis. The pit connections between gonimoblast cells flare out. They remain as isolated bodies without connection to a wall after fusion. Secondary pit connections occur between vegetative gametophyte cells and sterile carposporophyte cells. There are three different morphological types of pit connections.     

Two species of Dasya (Ceramiales, Rhodophyta) from Bonin Islands, southern Japan, with the description of Dasya boninensis sp. nov.

Two species of Dasya in the Dasyaceae (Ceramiales, Rhodophyta) are reported from Bonin Islands, southern Japan. Dasya murrayana Abbott et Millar, new to Japan, is characterized by the following set of features: the tufted habit (up to 30 erect axes developing from a basal disc), small‐sized (6–10 mm high and 350–500 μm in diameter in the middle region), thinly but completely corticated axes, rigid and incurved pseudolaterals forming corymbose heads at the apices of axes and branches, the absence of adventitious monosiphonous filaments, a large number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral and slender spermatangial branches (35–45 μm in diameter). Dasya boninensis Masuda, Kurihara et Kogame, sp. nov. is characterized by short but thick (10–30 mm high and 600–1000 μm in diameter at the middle portion), heavily corticated axes, indistinct pericentral cells except for the upper portion in transverse sections, soft, straight pseudolaterals and adventitious monosiphonous filaments densely covering the axis and branches, a small number of tetrasporangial stichidia and spermatangial branches per fertile pseudolateral, thick spermatangial branches (65–90 μm in diameter), and short‐necked cystocarps. A dichotomous key to the taxa found in Japanese waters is given.     

New red alga, Acanthopeltis longiramulosa sp. nov. (Gelidiales, Rhodophyta) from Jeju Island, Korea

A new red alga from Jeju Island, Korea is described. The alga is assigned to Acanthopeltis, Gelidiaceae by the characteristics of terete erect axes, sympodial growth, and suborbicular branchlets that are amplexi‐caul at the base. Acanthopeltis longiramulosaY. Lee et Kim is characterized by a discoid holdfast with a few stolons, rhizoids arising from the apex of the branchlet, an erect terete axis diverging into a few branches, longish obpyriform to lanceolate branchlets with smooth surfaces, and tetrasporangial stichidia or sper‐matangial and cystocarps appendages on the marginal region of the branchlet. A. longiramulosa is more closely related to Acanthopeltis japonica than Acanthopeltis hirsuta in terms of thallus morphology. However, A. longiramulosa is easily distinguished from A. japonica, which has suborbicular branchlets with setaceous processes on both surfaces.     

Additional analysis of chemical diversity of the red algal genus Laurencia (Rhodomelaceae) from Japan

The halogenated secondary metabolite constitution of four species of the red algal genus Laurencia (Rhodomelaceae) from southern Japan is reported. Laurencia composita Yamada from Tanegashima Island (Kagoshima Prefecture) bears five sesquiterpenoids (2,10‐dibromo‐3‐chloro‐α‐chamigrene and 2,10‐dibromo‐3‐chloro‐9‐hydroxy‐α‐chamigrene, in addition to pre‐pacifenol epoxide, johnstonol and pacifenol, which are known in other populations of this species). Laurencia intricata Lamouroux from Chinzei (Saga Prefecture) and Oomura Bay (Nagasaki Prefecture) bear a C₁₅ aceto‐genin, okamurallene. Laurencia majuscula (Harvey) Lucas from Tanegashima Island produces three sesquiterpenoids, (Z)‐10,15‐dibromo‐9‐hydroxy‐chamigra‐1, 3(15),7(14)‐triene, 10‐bromo‐7‐hydroxylaurene and 10,11‐dibromo‐7‐hydroxylaurene, corresponding to those of one of its chemical races. Laurencia venusta Yamada from Tanegashima Island produces two sesquiterpenoids, cupalaurenol and cyclolaurenol, which were known only from a sea hare, Aplysia dactylomela Rang. This strongly suggests that Aplysia consumes L. venusta and concentrates these halogenated compounds.     

Maullinia ectocarpii gen. et sp. nov. (Plasmodiophorea), an intracellular parasite in Ectocarpus siliculosus (Ectocarpales, Phaeophyceae) and other filamentous brown algae

An obligate intracellular parasite infecting Ectocarpus spp. and other filamentous marine brown algae is described. The pathogen forms an unwalled multinucleate syncytium (plasmodium) within the host cell cytoplasm and causes hypertrophy. Cruciform nuclear divisions occur during early development. Mature plasmodia become transformed into single sporangia, filling the host cell completely, and then cleave into several hundred spores. The spores are motile with two unequal, whiplash-type flagella inserted subapically and also show amoeboid movement. Upon settlement, cysts with chitinous walls are formed. Infection of host cells is accomplished by means of an adhesorium and a stachel apparatus penetrating the host cell wall, and injection of the cyst content into the host cell cytoplasm. The parasite is characterized by features specific for the plasmodiophorids and is described as a new genus and species, Maullinia ectocarpii.     

Incongruence of morphology and genetic markers in Hyles tithymali (Lepidoptera: Sphingidae) from the Canary Islands

Hyles t. tithymali on the Canary Islands has been observed to occur in two larval morphotypes, connected by intermediate forms along a geographical cline from east to west. In this study, it was tested whether this distribution of phenotypes reflects a genealogical division of the population. mtDNA sequence data (COI + II, tRNA-leu) and genomic fingerprints from intersimple sequence repeat (ISSR)-PCR data were used. The sequence data had low variation (max. 0.4%), and phylogenetic analyses did not reveal groups that correlated with the morphotype. The samples did not group according to their island of origin and the most common haplotype was shared among all islands. Although nine haplotypes occurred only on the westernmost islands, the data showed little phylogeographical structure. The population of H. t. tithymali appears to reflect a comparatively rapid and recent colonization event of the Canary Islands. The ISSR-PCR data were very variable and did not reveal patterns corresponding to morphological variation or geographical distribution. Although the two morphs observed may represent the first stage of differentiation between two lineages, the recent origin of H. t. tithymali provided insufficient time for complete lineage sorting of ancestral polymorphism. Hence, the population of Hyles t. tithymali on the Canary Islands appears genetically more homogeneous than that was expected from the phenotypic distribution of the two morphotypes in the population.     

Neosiphonia flavimarina gen. et sp. nov. with a taxonomic reassessment of the genus Polysiphonia (Rhodomelaceae, Rhodophyta)

Vegetative and reproductive development of Neosiphonia flavimarina gen. et sp. nov. (Rhodomelaceae, Ceramiales) from Bangpo on the western coast of Korea was investigated. This species is superficially similar to Polysiphonia, but differs distinctly from the latter in vegetative and reproductive structures. The plants attach by a solid disk composed of a dense cluster of rhizoids cut off from the pericentral cell wall, and bear erect indeterminate branches producing the lateral-branch initials from successive segments in a spiral arrangement. The procarps have a three-celled carpo-gonial branch. Spermatangial branches are formed on a primary branch of the trichoblasts, terminating in a single or occasionally two large, sterile cells. Tetra-sporangia are produced from the second pericentral cell adjacent to the trichoblast basal cell on indeterminate branches, and arranged spirally. Comparing several taxonomic characters among related genera, Neosiphonia occupies an independent phylogenetic position from Polysiphonia and leads to the conclusion that the genus may have a strong link with Fernandosiphonia which has a unilateral branching system. Relevant nomenclatural changes for several Polysiphonia species are also proposed.