Freshwater Bryozoan Species Research Articles

New Record of Two Freshwater Bryozoan Species (Phylactolaemata) from Kagzipura Reservoir, Aurangabad, Maharashtra, India

A reassessment of the freshwater Bryozoa (Phylactolaemata) has carried out for two years at Kagzipura lake, 40 km northwest of Aurangabad, Maharashtra, India. Collected samples were primarily identified on the basis of their colony morphology and statoblast features under light microscope, and species identification was confirmed on the basis of Scanning Electron Microscopic Images (SEM) of statoblast and standard keys of freshwater Bryozoa. In the present study we are reporting two bryozoan species first time at Kagzipura lake which were not reported earlier at this region. So this paper has updated the bryozoan diversity of Kagzipura lake with two more species i.e. Hyalinella lendenfeldi (Ridley, 1886) and Plumatella bombayensis Annandale, 1908. The present study also provided brief descriptions of these species, including images taken with light microscope and Scanning Electron Microscope.

First record of a freshwater bryozoan species in Cuba: Plumatella repens (Linnaeus, 1758) (Phylactolaemata, Bryozoa).

The discovery of Plumatella repens floatoblasts in wetlands of the La Niña Bonita Reservoir and the Ciénaga de Zapata Swamp, Cuba, constitutes the first record of a freshwater bryozoan species on the island and extends the distribution range of the species in the insular Caribbean. Unlike the inland waters of the Lesser Antilles the greater availability of water and lower salinity are likely the main factors that determine the distribution of P. repens in the Greater Antilles.

To remain or leave: Dispersal variation and its genetic consequences in benthic freshwater invertebrates.

Variation in dispersal capacity may influence population genetic variation and relatedness of freshwater animals thus demonstrating how life‐history traits influence patterns and processes that in turn influence biodiversity. The majority of studies have focused on the consequences of dispersal variation in taxa inhabiting riverine systems whose dendritic nature and upstream/downstream gradients facilitate characterizing populations along networks. We undertook extensive, large‐scale investigations of the impacts of hydrological connectivity on population genetic variation in two freshwater bryozoan species whose dispersive propagules (statoblasts) are either attached to surfaces (Fredericella sultana) or are released as buoyant stages (Cristatella mucedo) and that live primarily in either lotic (F. sultana) or lentic environments (C. mucedo). Describing population genetic structure in multiple sites characterized by varying degrees of hydrological connectivity within each of three (or four) UK regions enabled us to test the following hypotheses: (1) genetic diversity and gene flow will be more influenced by hydrological connectivity in populations of C. mucedo (because F. sultana dispersal stages are retained); (2) populations of F. sultana will be characterized by greater genetic divergence than those of C. mucedo (reflecting their relative dispersal capacities); and (3) genetic variation will be greatest in F. sultana (reflecting a propensity for genetic divergence as a result of its low dispersal potential). We found that hydrological connectivity enhanced genetic diversity and gene flow among C. mucedo populations but not in F. sultana while higher overall measures of clonal diversity and greater genetic divergence characterized populations of F. sultana. We suggest that genetic divergence over time within F. sultana populations reflects a general constraint of releasing propagules that might eventually be swept to sea when taxa inhabit running waters. In contrast, taxa that primarily inhabit lakes and ponds may colonize across hydrologically connected regions, establishing genetically related populations. Our study contributes more nuanced views about drivers of population genetic structures in passively dispersing freshwater invertebrates as outlined by the Monopolization Hypothesis (Acta Oecologica, 23, 2002, 121) by highlighting how a range of demographic and evolutionary processes reflect life‐history attributes of benthic colonial invertebrates (bryozoans) and cyclically parthenogenetic zooplankton. In addition, growing evidence that genetic divergence may commonly characterize populations of diverse groups of riverine taxa suggests that organisms inhabiting lotic systems may be particularly challenged by environmental change. Such change may predispose riverine populations to extinction as a result of genetic divergence combined with limited dispersal and gene flow.Open Research Badges This article has earned an Open Data Badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.5061/dryad.1tm8705.

An example of a possible leech-bryozoan association in freshwater.

Associations of various invertebrate species with bryozoans and sponges are a well-known marine phenomenon but such epizooic communities are far less diverse in freshwater environments. Here an occurrence of numerous leeches Alboglossiphoniacf.papillosa (Braun, 1805), in interstitial spaces between zooids of a colony of the freshwater bryozoan species Plumatellaaff.fungosa (Pallas, 1768) in Eastern Siberia is described. To the best of our knowledge, this record appears to be the first known example of a leech-bryozoan association, although such relationships deserve further research.

Freshwater bryozoans of Lithuania (Bryozoa).

Nine species of freshwater bryozoans were recorded in Lithuania in a survey of 18 various types of freshwater bodies. Eight species were assigned to the Class Phylactolaemata and families Plumatellidae and Cristatellidae (Plumatella repens, Plumatella fungosa, Plumatella fruticosa, Plumatella casmiana, Plumatella emarginata, Plumatella geimermassardi, Hyalinella punctata and Cristatella mucedo). The ninth species, Paludicella articulata, represented the Class Gymnolaemata. Plumatella geimermassardi and P. casmiana were recorded for the first time in Lithuania. For the plumatellids, species identification was achieved partly by analysing statoblasts’ morphological ultrastructures by scanning electron microscopy.

Food selection by Plumatella geimermassardi Wood and Okamura, 2004 (Phylactolaemata, Bryozoa)

Bryozoans are sessile filter feeding organisms able to play an important role in the cycling of organic matter in freshwater ecosystems. However, the quality and quantity of food particles ingested by bryozoans are still not well-known. Therefore, an experimental design was performed in order to investigate the clearance rate (CR), food selection and efficiency of assimilation by the freshwater bryozoan species Plumatella geimermassardi. P. geimermassardi was collected from the Colfiorito Marsh (Umbrian Natural Park, Italy), during summer. A higher grazing rate of suspended and dissolved solids was evidenced in the colonies collected in June, July, than in August. Food selection and assimilation of phytoplankton were determined. The algal species ingested as diet food item and those excreted with the faecal pellets were taxonomically identified. The results provide new information on CR and food selection by P. geimermassardi and enhance knowledge on its biology. Insights on feeding preferences by bryozoan species can provide valid information about their feasible distribution and abundance.

New species, genera, families, and range extensions of freshwater bryozoans in Brazil: the tip of the iceberg?

This paper reports the occurrence of 11 species of freshwater bryozoans collected from the States of Pará and São Paulo, Brazil, including two new genera and four new species. Two new families are erected, Tapajosellidae n. fam. in the Class Phylactolaemata, and Natanellidae n. fam. in the Class Gymnolaemata, Order Ctenostomata. One new genus, Tapajosella n. gen., accommodates the new phylactolaemate genus and species, Tapajosella elongata n. sp. The other new genus, Natanella n. gen., includes the former ctenostome, Hislopia natans, now Natanella natans n. comb. Other new species are the phylactolaemates, Plumatella pirassununga n. sp., Plumatella jariensis n. sp., and Fredericella tenax n. sp. Additional species include the ctenostome Hislopia corderoi Mané-Garzón, 1960, and the phylactolamates Plumatella osburni (Rogick & Brown, 1942), Plumatella siolii Wiebach, 1970, Plumatella casmiana Oka, 1907, Plumatella marcusi Wiebach, 1970, and possibly Plumatella philippinensis Kraepelin, 1887. The notable expansion in diversity of freshwater bryozoans from Brazil revealed by material amassed during brief and spatially-limited collection is suggestive of considerable undiscovered diversity in this poorly studied region of the world.

Pectinatella magnifica (Leidy, 1851) (Bryozoa, Phylactolaemata), a biofouling bryozoan recently introduced to China

Freshwater biofouling threatens a variety of human activities, from the supply of water and energy to recreation. Several species of freshwater bryozoans are notorious for clogging pipes and filters but have been relatively poorly studied to date. We report, for the first time, a biofouling species of freshwater bryozoan, Pectinatella magnifica (Leidy, 1851), from several freshwater rivers, lakes and ponds in China. A complete description, national distribution and the fouling problems are provided. Exactly how Pectinatella magnifica arrived in China remains unclear, but anthropochory and zoochory are considered to be important dispersal pathways.

Ecology of Pectinatella magnifica and associated algae and cyanobacteria

The freshwater bryozoan species Pectinatella magnifica was found in 6 sandpits and in 19 mostly extensively managed ponds in the Protected Landscape Area and Biosphere Reserve Třeboňsko (Czech Republic) from its first record (in 2003) to 2012. Mean fresh biomass and abundance of P. magnifica colonies were 0.6 ± 1.5 kg m−2 and 0.7 ± 1.1 colony m−2 (± SD), respectively, in the shoreline zone during the growing season 2006–2011. The maximum biomass was mostly recorded during the first half of August in all basins. Colonization of further localities was recorded rather than increasing of P. magnifica biomass or abundance in 2012. There were no correlations between water temperature or water transparency and biomass/abundance of P. magnifica during the growing season. P. magnifica colonies preferred to grow on the branches or roots (especially of Salix sp.) to aquatic macrophytes and stones. Most of the water bodies, where this bryozoan species occurred, had lower concentration of total phosphorus in the water when compared with the typical fishponds in the Czech Republic. Inner space of colonies of P. magnifica provided suitable higher trophic level substrate when compared with the water of the sandpits/fishponds especially for green coccal algae. A massive algal colonization was indentified in decomposing colonies at the end of the growing season.

Identification of five bryozoan species in the Northern Mallee Pipeline, Australia

Five species of freshwater bryozoans were identified in the Northern Mallee Pipeline (NMP) system in Victoria, Australia, from statoblast morphology using scanning electron microscopy. The five species were Plumatella emarginata, Fredericella australiensis, Plumatella reticulata, Rumarcanella minuta and Fredericella sultana. The latter three of these have never previously been reported as occurring on the Australian continent and samples have been preserved for safekeeping at Victoria University. The statoblasts were isolated from samples collected as intact colonies from filters and membranes at a number of different locations.

Divergence and species discrimination in freshwater bryozoans (Bryozoa: Phylactolaemata)

We explored the suitability of nuclear and mitochondrial ribosomal markers [small subunit nuclear ribosomal RNA gene, large subunit nuclear ribosomal RNA gene, and a region spanning partial small mitochondrial ribosomal RNA subunit, four transfer RNA genes, and partial large mitochondrial ribosomal RNA subunit (referred to as rrnS-rrnL)] for resolving patterns of diversification of 27 freshwater bryozoan species (class: Phylactolaemata) and evaluated the utility of statoblast ultrastructural features and molecular phylogenies for species discrimination in the Fredericellidae and Plumatellidae. Molecular data identified Plumatella fruticosa as distinct from the rest of the plumatellids, rendering the latter polyphyletic. rrnS-rrnL was the most suitable marker for species discrimination and identified two undescribed species of Plumatella and at least two undescribed species of Fredericella. Lack of wide dispersal by fredericellid statoblasts may underlie the observed propensity for cryptic speciation and phylogeographical structure in Fredericella. Conversely, the strong dispersal potential of plumatellid statoblasts may mediate efficient gene flow between distant populations and explain the relatively low intraspecific divergence and lack of evidence for cryptic speciation. We show that species identification based on external features of statoblasts can be problematic in both genera, including for a putatively highly invasive, biofouling species, Plumatella vaihiriae, thereby highlighting the utility of rrnS-rrnL sequences for species barcoding. © 2013 The Linnean Society of London

Form and metabolic scaling in colonial animals

Benthic colonial organisms exhibit a wide variation in size and shape and provide excellent model systems for testing the predictions of models that describe the scaling of metabolic rate with organism size. We tested the hypothesis that colony form will influence metabolic scaling and its derivatives by characterising metabolic and propagule production rates in three species of freshwater bryozoans that vary in morphology and module organisation and which demonstrate two- and three-dimensional growth forms. The results were evaluated with respect to predictions from two models for metabolic scaling. Isometric metabolic scaling in two-dimensional colonies supported predictions of a model based on dynamic energy budget theory (DEB) and not those of a model based on fractally branching supply networks. This metabolic isometry appears to be achieved by equivalent energy budgets of edge and central modules, in one species (Cristatella mucedo) via linear growth and in a second species (Lophopus crystallinus) by colony fission. Allometric scaling characterised colonies of a three-dimensional species (Fredericella sultana), also providing support for the DEB model. Isometric scaling of propagule production rates for C. mucedo and F. sultana suggests that the number of propagules produced in colonies increases in direct proportion with the number of modules within colonies. Feeding currents generated by bryozoans function in both food capture and respiration, thus linking metabolic scaling with dynamics of self-shading and resource capture. Metabolic rates fundamentally dictate organismal performance (e.g. growth, reproduction) and, as we show here, are linked with colony form. Metabolic profiles and associated variation in colony form should therefore influence the outcome of biotic interactions in habitats dominated by colonial animals and may drive patterns of macroevolution.

First finding of freshwater bryozoans Lophopodella carteri Hyatt, 1866 in the Kylian delta of the Danube River

The freshwater bryozoan species Lophopodella carteri (Hyatt, 1866) new to Ukraine was found in the mouth of the Bystryi arm (Kylian delta of the Danube River) as a component of the fouling community.

First record of freshwater bryozoans (Bryozoa: Phylactolaemata) in the aquatic invertebrate fauna of Serbia

Species of freshwater bryozoans are newly recognized in the fauna of aquatic invertebrates in Serbia. This first record includes a total of five species of class Phylactolaemata found at eight localities during limnological investigations in the period from 2002 to 2006. Four species are assigned to family Plumatellidae ( Plumatella casmiana, P. emarginata, P. geimermassardi and Hyalinella punctata). Family Cristatellidae is represented by one species ( Cristatella mucedo). The freshwater bryozoans in the form of intact colonies and especially as dormant bodies were identified to the species level. The identification was done using scanning electron microscopy, analyzing resting bodies’ morphological ultrastructure.

Phylogenetic relationships of freshwater bryozoans (Ectoprocta, Phylactolaemata) inferred from mitochondrial ribosomal DNA sequences

Most species of freshwater bryozoans (Ectoprocta: Phylactolaemata) have few morphological distinctions, and within phylactolaemates, the morphology of the statoblast has been used to determine evolutionary relationships. Here, two controversial phylogenies have been proposed for phylactolaemates with regard to the relationship of Lophopodidae to other families. Two plumatellid genera, Gelatinella and Hyalinella, are candidates for the ancestral type of lophopodids. In addition, the coexistence of spines on the surfaces of the statoblast has led to the suggestion that lophopodids are closely related to the family Cristatellidae. In this study, we analysed mitochondrial DNA sequences of the 12S and 16S rDNA genes of 10 phylactolaemate species. Our results suggest that plumatellids may not be a direct ancestral group of lophopodids and that cristatellids are not a sister group of lophopodids. Fredericella, which was previously thought to be an ancestral group, was revealed to be derived. In addition, our results suggest that Stephanella is the most basal phylactolaemate. Mapping morphological characteristics onto the sequence‐based phylogenetic tree revealed convergent evolution of statoblast characters.

Molecular evidence of release of Tetracapsula bryosalmonae, the causative organism of proliferative kidney disease from infected salmonids into the environment

Keywords: Bryozoa, polymerase chain reaction, pro-liferative kidney disease, Tetracapsula bryosalmonae,transmission.Tetracapsula bryosalmonae is the malacosporeanparasite that causes the commercially importantproliferative kidney disease (PKD) in culturedsalmonids (Canning, Curry, Feist, Longshaw O Kent, Khattra, Hervio & Devlin1998; Morris, Adams & Richards 1999). However,because of the lack of hard spore valves and theinflammatory nature of the disease it was widelyconsidered that the observed spores were not viable(Kent & Hedrick 1986). The discovery that speciesof freshwater bryozoans could be infected withT. bryosalmonae demonstrated that within thesehosts the parasite formed spores that did not possesshard spore valves (Canning et al. 1999). Tetracap-sula bryosalmonae stages obtained from bryozoanswere subsequently proven to be able to infectrainbow trout, Oncorhynchus mykiss (Walbaum),resulting in clinical PKD. This suggested that thespore stages observed in the bryozoan hosts wereviable and capable of transmitting the parasite(Feist, Longshaw, Canning & Okamura 2001).It is well documented that the sporogonic stagesof T. bryosalmonae can persist in the tubulelumens of salmonids many months after the fishhave recovered from clinical PKD (Kent H Kent et al. 1998; Morris, Adams,Feist, McGeorge & Richards 2000). This has ledto suggestions that the T. bryosalmonae sporestages observed in salmonids are viable andcapable of infecting bryozoan hosts (Kent,Khattra, Hedrick & Devlin 2000). Limited workhas been performed examining the release of sporestages from infected salmonid species. Kent &Hedrick (1986) examining 10 rainbow troutcollected from a hatchery in North Americaenzootic for PKD reported the presence of asmall number of sporoblasts in the urine of one ofthe fish which were presumed to be T. bryosal-monae. However, so far T. bryosalmonae spores orsporogonic stages have yet to be identified incollecting ducts, ureters or the urinary bladder ofany salmonid fish.This short communication describes bothmolecular evidence confirming that T. bryosalmonaeis released from salmonids into the freshwaterenvironment and the results of a preliminaryexperiment to transmit T. bryosalmonae from browntrout, Salmo trutta L., to a freshwater bryozoan.

Plumatella mukaii, a new phylactolaemate bryozoan from Asia and South America

A new freshwater bryozoan species, Plumatella mukaii, is recognized from eastern Asia and western South America. Colonies and statoblasts both bear a resemblance to P. emarginata, and have often been confused with that species, especially in Japanese studies. Floatoblasts and sessoblasts are enclosed within a tough, wrinkled, membrane which resists removal by mechanical means. Floatoblasts are generally smaller than those of P. emarginata, but display unusually high variability in their overall dimensions. The species has been reported from both lentic and lotic habitats. In Asia, the range includes Japan, Korea, China, India and Indonesia. It has most recently also been found at several sites in Chile. The recognition of P. mukaii narrows the previously reported range of P. emarginata and invites a re-inspection of that species worldwide.

Reappraisal of Australian freshwater bryozoans with two new species of Plumatella (Ectoprocta : Phylactolaemata)

Of the 10 species of freshwater bryozoans previously reported from Australia, only Fredericella australiensis, Hyalinella lendenfeldi and Lophopodella carteri can be positively confirmed from existing preserved material. From a survey of all known museum collections of freshwater bryozoans comes compelling evidence that a specimen labelled ‘Plumatella toanensis’ is actually Hyalinella lendenfeldi, including the only known statoblasts of this species. Plumatella agilis is recognised tentatively pending new material. Fredericella sultana, Plumatella emarginata and P. repens are not represented by any known specimens, although they are likely to occur in Australia. Hyalinella punctata and Gelatinella toanensis have been previously reported in error. Two other previously misidentified specimens, including Hyalinella vaihiriae, are now reported as new species: Plumatella velata and P. rieki. A taxonomic key is given for Australian freshwater bryozoan species, including species both verified from Australia and others only presumed to occur there.

Differentiation of North American and European forms of Fredericella sultana (Blumenbach) (Ectoprocta: Phylactolaemata)

Fredericella sultana (Blumenbach, 1779) has long been considered one of the few freshwater bryozoan species with a truly cosmopolitan distribution. However, chromosome spreads from European material show 2n = 16 compared to 2n = 14 in North American specimens. In laboratory rearing the two forms are morphologically indistinguishable except for the surface texture of their statoblasts. Smooth statoblasts of European colonies match early illustrations of the species, while the densely pitted statoblasts of the North American form resemble those of F. indica Annandale 1909. On the basis of these observations we tentatively designate the North American ‘F. sultana’ as F. indica. The only known American species with smooth statoblasts is F. australiensis Goddard 1909, in which the 2n = 16 karyotype is similar or identical to European F. sultana; however, despite this karyotypic similarity the two species retain their distinguishing morphology when reared together in the laboratory. Two enzymes from a single specimen of European F. sultana were electrophoretically distinct from the corresponding enzymes present in samples of both F. australiensis and North American ‘F. sultana’. Four phosphoglucose isomerase alleles were present in North American ‘F. aultana’ from four geographically separated collection sites, although only one genotype for this locus was observed in material from any one site. These genetic findings are consistent with a relatively short-range dispersal potential in this species as compared to Plumatella species.