Heavy infection of Diodon hystrix by the copepod Peniculisa wilsoni (Siphonostomatoida, Pennellidae

Heavy infections of the copepod Peniculisa wilsoni are reported from the fins of Diodon hystrix.     

The biology of the spiny icefish <Emphasis Type="Italic">Chaenodraco wilsoni</Emphasis> Regan, 1914

The most abundant ice fish species observed in catches off the northern tip of the Antarctic Peninsula in the last 25–30 years has been the spiny ice fish Chaenodraco wilsoni Regan 1914. C. wilsoni has been exploited on a commercial scale from the late 1970s to the end of the 1980s off Joinville–D’Urville Islands (CCAMLR Statistical Subarea 48.1) and in the Cosmonauts and Cooperation Seas and Prydz Bay in the Indian Ocean sector (CCAMLR Statistical Division 58.4.2). This paper presents new information on biological features and life history characteristics of C. wilsoni, based on research survey collections along the northern Antarctic Peninsula in 2006 and 2007 and samples taken in the commercial fishery in 1987. Length frequency compositions from the research surveys demonstrated that fish 21–34 cm long predominated in the catches. Sexual maturity is attained at 24–25 cm. Absolute fecundity and relative fecundity is low (1,000–2,500 eggs; 6–12 eggs). Oocyte diameter varied from 4.0 to 4.9 mm very close to spawning. Spawning at the tip of the Antarctic Peninsula is likely to occur in October–November. Remotely operated vehicle deployments in the northern Weddell Sea demonstrated that C. wilsoni exhibit parental nest guarding where males protect the eggs. The incubation period is likely to be 8 months long. Fish feed primarily on Antarctic krill (Euphausia superba) in the Antarctic Peninsula region and in the Cosmonauts and Cooperation Seas while fish take ice krill (Euphausia crystallorophias), Pleuragramma antarcticum and myctophids to some extent in other areas. Age determination still awaits validation. Preliminary ageing attempts suggested a maximum age of about 8–10 years.     

A phylogeny of Vesiculariidae (Bryozoa,Ctenostomata) supports synonymization of three genera and reveals possible cryptic diversity

Compared to their calcified sister group, order Cheilostomata, uncalcified ctenostome bryozoans exhibit relatively simple and often inconsistent morphologies, making them particularly suitable candidates for the use of molecular tools to delimit species and examine their interrelationships. The family Vesiculariidae is composed of six genera, three of which, Zoobotryon, Avenella and Watersiana are monotypic, and one, Vesicularia, encompasses four species. The majority of vesiculariid diversity, however, is found in Amathia (39 species) and Bowerbankia (21 species). The respective monophyletic status for Amathia and Bowerbankia has recently been put into question by molecular evidence and is being further examined in this study. Multigene (ssrDNA, rrnL, cox1) phylogenetic analysis revealed that Bowerbankia is paraphyletic to the inclusion of Zoobotryon and Amathia, where the latter was resolved as non‐monophyletic. Although Vesicularia also nested within this paraphyletic assemblage in some of the analyses, Bayesian topology testing did not support this result. Our results are discussed within the context of published morphological evidence and lead to the conclusion that Bowerbankia and Zoobotryon should be classified as junior subjective synonyms of Amathia. A revised nomenclature is provided. Furthermore, we examined genetic divergences between widely distributed supposed conspecific species and discovered possible cryptic diversity in the outgroup taxon Anguinella palmata and in Bowerbankia citrina, Amathia vidovici and Amathia crispa.     

The diet of the Weddell Seal Leptonychotes weddellii at the Danco Coast, Antarctic Peninsula

The diet of the Weddell Seal Leptonychotes weddellii at the Danco Coast, Antarctic Peninsula, was investigated by the analysis of 105 and 39 faeces collected at beaches surrounding Cierva Point during January–March 1998 and 2000, respectively. The diet was diverse and composed of both pelagic and benthic-demersal organisms. Fish, followed by cephalopods, constituted the bulk of the diet by number and mass. Among fish, Pleuragramma antarcticum, Chaenodraco wilsoni and Gobionotothen gibberifrons were the dominant fish by mass in 1998, whereas Chionodraco rastrospinosus, P. antarcticum and C. wilsoni predominated by mass in 2000. The contribution of channichthyid species to the diet of seals at the Danco Coast was higher than previously reported. Besides those species, the myctophid Electrona antarctica was also an important prey by number in the diet of seals in both summer seasons. The results are compared with information from other study areas and the possibility of using information on the diet of this seal as a gross indicator of fish availability/distribution is considered.     

Bryozoan populations reflect nutrient enrichment and productivity gradients in rivers

1. The hypothesis that nutrient enrichment will affect bryozoan abundance was tested using two complementary investigations; a field‐based method determining bryozoan abundance in 20 rivers of different nutrient concentrations by deploying statoblast (dormant propagule) traps and an experimental laboratory microcosm study measuring bryozoan growth and mortality. These two methods confirmed independently that increased nutrient concentrations in water promote increases in the biomass of freshwater bryozoans. 2. Statoblasts of the genus Plumatella were recorded in all rivers, regardless of nutrient concentrations, demonstrating that freshwater bryozoans are widespread. Concentrations of Plumatella statoblasts were high in rivers with high nutrient concentrations relative to those with low to moderate nutrient concentrations. Regression analyses indicated that phosphorus concentrations, in particular, significantly influenced statoblast concentrations. 3. Concentrations of Lophopus crystallinus statoblasts were also higher in sites characterised by high nutrient concentrations. Logistic regression analysis revealed that the presence of L. crystallinus statoblasts was significantly associated with decreasing altitude and increasing phosphorus concentrations. This apparently rare species was found in nine rivers (out of 20), seven of which were new sites for L. crystallinus. 4. Growth rates of Fredericella sultana in laboratory microcosms increased with increasing nutrient concentration and high mortality rates were associated with low nutrient concentrations. 5. Our results indicate that bryozoans respond to increasing nutrient concentrations by increased growth, resulting in higher biomasses in enriched waters. We also found that an important component of bryozoan diets can derive from food items lacking chlorophyll a. Finally, bryozoans may be used as independent proxies for inferring trophic conditions, a feature that may be especially valuable in reconstructing historical environments by assessing the abundance of statoblasts in sediment cores.     

Symbiosis of cornulitids with the cystoporate bryozoan Fistulipora in the Pridoli of Saaremaa,Estonia

Cornulites sp. and Fistulipora przhidolensis formed a symbiotic association in the Pridoli (latest Silurian) of Saaremaa Island, Estonia. This Cornulites sp.–F. przhidolensis association is the youngest example of cornulitid–bryozoan symbiosis. Symbiosis is indicated by intergrowth of both organisms. The cornulitids are completely embedded within the cystoporate bryozoan colony, leaving only their apertures free on the growth surface of bryozoan. In terms of food competition, this association could have been slightly harmful to F. przhidolensis as Cornulites sp. may have been a kleptoparasite. There may have been a small escalation in the evolution of the endobiotic life mode of cornulitids as the number of such associations increased from the Ordovician to Silurian. It is likely that Palaeozoic bryozoan symbiosis reached its maximum in the Late Ordovician. Most of the symbiotic bryozoans in the Palaeozoic are trepostomes, and the diversity of symbiotic associations was also greatest among trepostomes.     

Epibiont foraminifera of Sertella frigida (Waters) (Bryozoa, Cheilostomata) from Terranova Bay, Ross Sea, Antarctica

Several arenaceous and calcareous foraminifera epibionts of Sertella frigida (Waters) (Bryozoa, Cheilostomata), collected in Terranova Bay during the 1989–90 Italian Antarctic expedition, were studied. Arenaceous species, such as Psammosphaera fusca Schulze f. adhearescens Rhumbler, Haplophragmoides canariensis d'Orbigny, Portatrochammina antarctica (Parr), and Trochammina arctica Hedley, Hurdle and Burdett, are a conspicuous component of the epifaunal community. The calcareous foraminifers encrusting S. frigida are mostly represented by Cibicides refulgens Montfort and Rosalina globularis d'Orbigny. Foraminifera were found only in the basal part of the bryozoan colonies. The presence of many juveniles provided evidence that foraminifers were reproducing at the time of sampling. Psammosphaera fusca f. adhaerescens was found exclusively inside the zooids of S. frigida. The large number of individuals associated with the bryozoan suggest that P. fusca f. adhaerescens finds optimum conditions (shelter, food, and grains for shell building) for growth inside the zooids of S. frigida. The other species occurred most commonly adhered to the trabeculae or to the zooid orifices of S. frigida. An elevated position offers a better chance to catch food particles from the overlying water column. Foraminifers could benefit also from bryozoan feeding currents. The availability of resuspended organic material could provide a more consistent source of food in a highly seasonal oligotrophic environment. Received: 8 February 1995/Accepted: 30 June 1996     

Synthesis and biological activities of the marine bryozoan alkaloids convolutamines A, C and F, and lutamides A and C

Synthesis of convolutamines and lutamides, new 2,4,6-tribromo-3-methoxyphenethylamine alkaloids isolated from Floridian marine bryozoan Amathia convoluta, was accomplished by a sequence of reactions starting from 3-hydroxyphenethylamines. Cytotoxities of the synthetic lutamides, convolutamines and their de-O-methyl derivatives were examined using drug-sensitive and -resistant P388 as well as KB cell lines. The bioassay suggests that the 2,4,6-tribromo-3-methoxyphenethylamine is an indispensable unit for detection of the activities. Additionally, a reversal of drug resistance by those alkaloids is recognized.     

New trepostome Bryozoa from the Early Triassic (Smithian/Spathian) of Nevada

Two new bryozoan species of the trepostome family Dyscritellidae,Dyscritellopsis thaynesianus n. sp. andDyscritellopsis montelloensis n. sp., are described from the Early Triassic (Smithian/Spathian) Thaynes Limestone, Nevada (USA). The bryozoan fauna documents the survival of Paleozoic lineages into the earliest Triassic on northern open shelves outside the tropics. The fauna holds paleobiogeo-graphic connections to the Early Triassic bryozoan faunas of Spitsbergen.      

Monohalogenated maleimides as potential agents for the inhibition of Pseudomonas aeruginosa biofilm

New monohalogenated maleimide derivatives (with bromine, chlorine or iodine) were synthesized to test the effect of halogen atoms in inhibiting the formation of Pseudomonas aeruginosa biofilm. The evaluation of their biological activities clearly defines a structure–activity relationship. In this study, the bactericidal action of the three compounds was observed at the concentration range 0.3–5.0 mM on Luria-Bertani agar plates. The halogen atom of these molecules was critical in modulating the antibacterial activity, with a slightly higher effectiveness for chlorine. Confocal laser scanning microscopy was used to examine P. aeruginosa biofilms cultivated in flow cells. At concentration as low as 40 μM, the bromine and iodine compounds displayed a total inhibition towards the formation of bacterial biofilm. At this concentration, the bacterial attachment to glass surfaces was strongly affected by the presence of bromine and iodine whereas the chlorine derivative behaved as a bactericidal compound. A bioluminescent reporter strain was then used to detect the effect of the chemically synthesized maleimides on quorum sensing (QS) in P. aeruginosa. At the concentration range 10–100 μM, bioluminescence assays reveal that halogenated maleimides were able to interfere with the QS of the bacterium. Although the relationship between the weak inhibition of cell-to-cell communication (15–55% of the signal) and the high inhibition of biofilm formation has not been elucidated clearly, the results demonstrate that bromo- and iodo-N-substituted maleimides bromine and iodine may be used as new potent inhibitors that control bacterial biofilms.     

Anatomy of the larva of Amathia vidovici (Bryozoa: Ctenostomata) and phylogenetic significance of the vesiculariform larva

Amathia vidovici (Vesiculariidae) has a lecithotrophic coronate larva. The apical disc of A. vidovici larvae is more complex than that of other vesiculariids and includes a new cell type, which may be glial-like in function. A massive nerve nodule consists only of neural processes; as no ganglia or other evidence of interneurons were found, sensory cells apparently innervate their effectors directly. Putative synaptic junctions within the nerve nodule indicate that both receptor and effector cells send processes to this neuropile. Some 44 intercoronal cells of three types, two of which are new, are interspersed among the approximately 40 coronal cells. Juxtapapillary bodies, a unique sensory complex previously known only from Bowerbankia gracilis larvae, also occur in A. vidovici. A large refractile body, which is of uncertain function and is positioned near the center of the larva, is described for the first time. A comparison of vesiculariid larvae that have been studied at the ultrastructural level reveals that larvae of Amathia vidovici and Bowerbankia gracilis are more similar to each other than either is to B. imbricata. Differences between the two Bowerbankia species, however, may reflect relative detail of their study and differences in interpretation rather than intergenic plasticity. Nevertheless. a distinctive suite of larval characteristics are shared by other members of the family Vesiculariidae, justifying a specific name—vesiculariform—for their larvae. A number of the defining characteristics of vesiculariform larvae also appear in the carnosan superfamily Victorelloidae. This finding is consistent with arguments based on adult characteristics that the Victorelloidea are ancestral to the Vesicularioidea. If this geneology is correct, one can predict that those vesiculariform traits which originated in the victorellids are plesiomorphic not only to the Family Vesiculariidae but to all sister taxa placed in the Vesicularioidea. © 1993 Wiley-Liss, Inc.     

Four new species of Gomphocythere (Crustacea, Ostracoda) from Lake Tanganyika, East Africa

Four new species of the ostracod genus Gomphocythere are described from Lake Tanganyika (East Africa): Gomphocythere downingi n. sp. G. coheni n. sp., G. wilsoni n. sp., and G. woutersi n. sp. All species are endemic to the lake and are found within a variety of substrates and depths. The addition of these four new species brings the total number of endemic Gomphocythere species in Lake Tanganyika to nine. Other Gomphocythere species are known from water bodies throughout East and South Africa and in the Levant. Brooding is an important, but not a unique, preadaptation for the persistence and taxic prolific speciation of this lineage in Lake Tanganyika.     

Cryptostomid Bryozoans From The Sassito Formation,Upper Ordovician Cool‐Water Carbonates of the Argentinean Precordillera

Abstract: Two new bryozoan species are described from the Upper Ordovician Sassito Formation of the Argentinean Precordillera: Moyerella  spinata sp. nov. and Phylloporina  sassitoensis sp. nov. The bryozoans are found in cool‐water carbonates. The Silurian genus Moyerella is reported the first time in the Ordovician, showing palaeobiogeographic connections with Estonia and Siberia.     

The Resemblance of Bryozoan Gizzard Teeth to “Annelid-like” Setae

Abstract The gizzard teeth of a bryozoan (Bowerbankia imbricata) are found to be the structural homologues of certain epidermal derivatives, popularly known as “annelid-like” setae.     

BRACHIOPOD PALAEOECOLOGY IN MIDDLE DANIAN LIMESTONES AT FAKSE, DENMARK

The Danian limestone in the Fakse quarry displays banks of coral limestone interfingering with banks of bryozoan limestone. (1) Previous and present studies on the brachiopods show that ‘Rhynchonella’ flustracea Buch, ‘R.’ faxensis Posselt, ‘Terebratula’ mobergi Lundgren, and Argyrotheca pindborgi (Nielsen) are restricted to the coral limestone of Fakse. (2) Crania (Danocrania) transversa (Lundgren), C. (D.) tuberculata (Nilsson), Isocrania aff. egnabergensis (Retzius), ‘Terebratula’ fallax Lundgren, and Carneithyris incisa (Buch) are known from bryozoan limestone at Fakse and other Middle Danian localities. (3) Common to both kinds of sediments in Fakse quarry and found at other Middle Danian bryozoan limestone localities as well are Terebratulina aff. chrysalis (Schlotheim), Argyrotheca scabricula (Koenen), Megathiris bruennichi (Rosenkrantz), Platidia sp., and Thecidellina? groenwalli (Nielsen). (4) ‘Terebratula cincta’ Nielsen is restricted to Fakse quarry and occurs in both kinds of sediments. (5) Some of the species restricted to the coral limestone appear to be morphologically adapted to fit in between the branches of the dominant coral in Fakse quarry, Dendrophyllia candelabrum Hennig.     

Biodegradation of 2,4,6-Tribromophenol by Ochrobactrum sp. Strain TB01

A bacterium that utilizes 2,4,6-tribromophenol (2,4,6-TBP) as sole carbon and energy source was isolated from soil contaminated with brominated pollutants. This bacterium, designated strain TB01, was identified as an Ochrobactrum species. The organism degraded 100 μM of 2,4,6-TBP within 36 h in a growing culture. In addition, it released 3 mol of bromine ions from 1 mol of 2,4,6-TBP during the complete degradation of 2,4,6-TBP in a resting cell assay. Moreover, cells grown on 2,4,6-TBP degraded 2,6-dibromophenol (2,6-DBP), 4-bromophenol (4-BP), 2,4,6-trichlorophenol (2,4,6-TCP) and phenol. Metabolic intermediates were detected in the reaction mixture of an in vitro assay for 2,4,6-TBP, and they were identified as 2,4-DBP and 2-BP. NADH was required for the debromination of 2,4,6-TBP. These results suggest that 2,4,6-TBP is converted to phenol through sequential reductive debromination reactions via 2,4-DBP and 2-BP by this strain.     

The onset of invasion of bryozoan <Emphasis Type="Italic">Pectinatella magnifica</Emphasis> in South Bohemia (Czech Republic)

Pectinatella magnifica is an invasive freshwater bryozoan with ability to produce large colonies reaching a capacity of up to several tens dm³. In the Protected Landscape Area and Biosphere reserve Třeboňsko the bryozoan was first found in 2003 in one mesotrophic sandpit. The species gradually spread to many other sites around the Třeboň area and at most of these locations its occurrence has invasion properties. Pectinatella expanded to some other sandpits, fishponds without intensive pisciculture. Pectinatella colonies are found mainly on submerged branches of willow trees. The differences between biomass in transects with the occurrence of shrub willow and biomass in transects without their presence were statistically significant in the total biomass weight and the number of colonies. The average weight of several colonies did not differ. The most important parameter affecting the occurrence was the low trophy of water. The water temperature is evidently an important factor affecting the seasonal dynamics of occurence. Differences in nitrogen and phosphorous content between the water outside and inside the colonies were statistically significant. The colonies also accumulate other elements, including microelements.     

Colony Structure and Seasonal Differences in Light and Nitrogen Modify the Impact of Sessile Epifauna on the Giant Kelp Macrocystis pyrifera (L.) C Agardh

The presence of the stoloniferous hydroid Obelia geniculata (L.) had no effect on the pigment concentration or nitrogen status of underlying blade tissue of the giant kelp Macrocystis pyrifera (L.) C. Agardh. The sheet-like colonies of the bryozoan Membranipora membranacea (L.) markedly reduced the pigment concentration of colonized blade tissue, but only during winter. Reductions in pigment concentration are most likely a result of damage to underlying tissue due to some factor related to the presence of bryozoan colonies on blade surfaces. Blade tissue colonized by M. membranacea also had higher δ¹⁵N signatures than surrounding bryozoan-free tissue, possibly indicating the provision of nitrogen to M. pyrifera by bryozoan colonies. Results show that seasonal changes in nitrogen and colony size can strongly modify the effect of epifauna on macroalgae they colonize. Unlike bryozoans, hydroid colonies provided no barrier to nitrogen uptake by colonized M. pyrifera tissue and enhanced ammonium uptake was observed for tissue colonized by O. geniculata during nitrogen limitation. Epifauna with stoloniferous growth forms such as hydroids are more likely to have benign or even mutualistic relationships with macroalgae they colonize than the sheet-like colonies of bryozoans.     

Wenlock carbonate,level bottom,brachiopod-dominated communities from Wales and the Welsh Borderland

Four marine level bottom communities are described from Wenlock carbonate rocks (i.e. the Wenlock and Woolhope limestones) of Wales and the Welsh Borderland. The communities are: (1) Sphaerirhynchia wilsoni, (2) Isorthis clivosa, (3) Eoplectodonta duvalii, and (4) Visbyella trewerna. The Sphaerirhynchia wilsoni community is divided into: (a) an argillaceous micrite phase, and (b) a biomicrite phase. The communities and the phases are defined on the basis of consistent and recurrent numerical species combinations.The community spectrum from Sphaerirhynchia wilsoni to Visbyella trewerna is broadly correlated with an increase in water depth. The communities show no correlation with major limestone facies types. It is suggested that turbulence, rates of sedimentation and substrate type are some of the environmental parameters, in the shallow near-shore regime, which determine the distribution of brachiopods.