The unplumatellid Plumatella fruticosa found its home: Hirosella gen. nov. morphological arguments for the systematic placement of a freshwater bryozoan.

Bryozoans are colonial, suspension-feeding lophotrochozoans. The phylum consists of the large group of chiefly marine Myolaemata and the exclusively limnic Phylactolaemata. Each colony consists of individual zooids that comprise the protective cystid and the retractable polypide. Phylactolaemates are a small group of approximately 90 species in 6 families. They feature a body wall, that can either be gelatinous, as in the families Stephanellidae, Lophopodidae, Cristatellidae and Pectinatellidae, or encrusted, as in Plumatellidae and Fredericellidae. Morphological investigations of the most specious plumatellids are rare and focus on few species. Plumatella fruticosa is of particular interest in this regard, as it shows a mosaic of plumatellid and fredericellids characters. The most recent phylogeny clusters P. fruticosa with cristatellids and pectinatellids as sister groups to fredericellids. Hence, there is considerable doubt, whether P. fruticosa is truly a plumatellid. Therefore, this study aims to reinvestigate the morphology of P. fruticosa with confocal microscopy and section-based three-dimensional reconstruction. The new data show that P. fruticosa has numerous conspicuous stumps from fragmented proliferation buds, which are otherwise only known from fredericellids. Like fredericellids, P. fruticosa grows erect, but in contrast, has a horseshoe-shaped lophophore and floatoblasts. Besides the proportions of the lophophore, the tentacle sheath and digestive tract resemble a fredericellid-like situation. Myoanatomical details like the pronounced longitudinal muscles of the vestibular wall and tentacle sheath differ from plumatellids and favour the recently proposed scenario, which places P. fruticosa next to Pectinatellidae and Cristatellidae. In addition, the intertentacular membrane of P. fruticosa shows structural similarity to cristatellids as it is attached to the tentacles via lamellae. Taking all aspects into account, we erect a new family: Hirosellidae fam. nov. including the new genus Hirosella gen. nov.

Protomelission is an early dasyclad alga and not a Cambrian bryozoan.

The animal phyla and their associated body plans originate from a singular burst of evolution occurring during the Cambrian period, over 500 million years ago1. The phylum Bryozoa, the colonial 'moss animals', have been the exception: convincing skeletons of this biomineralizing clade have been absent from Cambrian strata, in part because potential bryozoan fossils are difficult to distinguish from the modular skeletons of other animal and algal groups2,3. At present, the strongest candidate4 is the phosphatic microfossil Protomelission5. Here we describe exceptionally preserved non-mineralized anatomy in Protomelission-like macrofossils from the Xiaoshiba Lagerstätte6. Taken alongside the detailed skeletal construction and the potential taphonomic origin of 'zooid apertures', we consider that Protomelission is better interpreted as the earliest dasycladalean green alga-emphasizing the ecological role of benthic photosynthesizers in early Cambrian communities. Under this interpretation, Protomelission cannot inform the origins of the bryozoan body plan; despite a growing number of promising candidates7-9, there remain no unequivocal bryozoans of Cambrian age.

Revision of the type species of some cheilostome bryozoan genera in the collection of the Swedish Museum of Natural History.

The zoological dry collection of the Swedish Museum of Natural History in Stockholm includes an important, historical bryozoan section that is rich in species and specimens and also diverse from a geographical point of view. This collection also contains the type specimens of the type species of some cheilostome bryozoan genera introduced by several naturalists and bryozoologists between the mid-1800s and 1900s. With a few exceptions, these have not been revised since the advent of scanning electron microscopy as a standard tool for bryozoan taxonomy. Here, the type specimen(s) of the type species of the following six cheilostome genera are described and illustrated using SEM micrographs for the first time: Cheilopora Levinsen, 1909; Fedorella Siln, 1947; Floridina Jullien, 1882; Lepraliella Levinsen, 1917; Smittipora Jullien, 1882; and Stenopsella Bassler, 1952. The type specimen(s) of the type species of the recently introduced Terwasipora Reverter-Gil Souto, 2019 and the relatively recently revised Doryporella Norman, 1903 are also illustrated for the first time. This revision has identified some erroneous geographical records for some of the species/genera examined, and has led to the proposed synonymy of Stenopsella with Gigantopora Ridley, 1881. Lectotypes have also been selected. All of the images produced will also be publicly available through the SMNH online catalogue. The digitisation of natural history museum collections, with prioritisation of historical type specimens, is of paramount importance to facilitate access to the fundamental taxonomic units for scientists worldwide.

Further species and range extensions of Amazonian bryozoans: chipping away at the iceberg.

A bryozoan survey conducted in the Amazon Basin in the vicinities of Manaus and Santarm during the high water season (May, 2018) revealed four new species described here: Fredericella adrianoi n. sp., Plumatella divae n. sp., Plumatella hartikainenae n. sp., and Plumatella spencerjonesae n. sp. Two of these species were encountered only once, suggesting that other undescribed species are likely to occur in the area. Range extensions were determined for two additional species: Plumatella pirassununga and Timwoodiellina natans. In addition, colonies were collected for the first time for two species previously known only by their statoblasts: Plumatella siolii and Plumatella marcusi. Statoblasts of Tapajosella elongata were encountered near Manaus, but the colonies remained elusive. The discovery of new species collected during two expeditions to the Amazon Basin in different seasons and years suggests that further diversity remains undetected in this and other poorly studied regions of the world. With few exceptions, plumatellid colonies described so far from the Amazon Basin are very similar in appearance, with branches wholly attached to the substratum and body walls that are soft, colorless, and transparent.

Fossil evidence unveils an early Cambrian origin for Bryozoa.

Bryozoans (also known as ectoprocts or moss animals) are aquatic, dominantly sessile, filter-feeding lophophorates that construct an organic or calcareous modular colonial (clonal) exoskeleton1-3. The presence of six major orders of bryozoans with advanced polymorphisms in lower Ordovician rocks strongly suggests a Cambrian origin for the largest and most diverse lophophorate phylum2,4-8. However, a lack of convincing bryozoan fossils from the Cambrian period has hampered resolution of the true origins and character assembly of the earliest members of the group. Here we interpret the millimetric, erect, bilaminate, secondarily phosphatized fossil Protomelission gatehousei9 from the early Cambrian of Australia and South China as a potential stem-group bryozoan. The monomorphic zooid capsules, modular construction, organic composition and simple linear budding growth geometry represent a mixture of organic Gymnolaemata and biomineralized Stenolaemata character traits, with phylogenetic analyses identifying P. gatehousei as a stem-group bryozoan. This aligns the origin of phylum Bryozoa with all other skeletonized phyla in Cambrian Age 3, pushing back its first occurrence by approximately 35 million years. It also reconciles the fossil record with molecular clock estimations of an early Cambrian origination and subsequent Ordovician radiation of Bryozoa following the acquisition of a carbonate skeleton10-13.

Coral reef-associated bryozoans of Jamaica.

As part of a long-term ecological study of the cryptic comunity of Jamaican coral reefs carried out by Jeremy B.C. Jackson and associates during the 1970s and early 1980s, collections were made of reef bryozoans found at 14 sites around the island. Space occupied by bryozoans on undercoral surfaces is dominated by relatively few species. However, during scanning electrone microscopy study and monograph preparation a diverse assortment of relatively rare species was discovered. Of the 132 species found, 56%, 74 species (70 cheilostomes and 4 cyclostomes) are new, as are one family (Inversiscaphidae) and 5 genera (Planospinella, Caribaria, Spirocoleopora, Gemellitheca, and Palliocella).

Phylum Bryozoa Ehrenberg, 1831 in the first twenty years of Zootaxa.

This short account is an invited contribution to the Zootaxa special volume 'Twenty years of Zootaxa.' Zootaxa was first published on 28 May 2001. Between this date and December 2020, 116 papers were published in Zootaxa that mention Bryozoa, comprising mostly descriptions of new species and higher taxa, but also including molecular sequencing (e.g. Fehlauer-Ale et al. 2011; Taylor et al. 2011; Franjevic et al. 2015), invasive-species research (e.g. Ryland et al. 2014; Vieira et al. 2014), checklists (e.g. Vieira et al. 2008), classification (e.g. Bock Gordon 2013), bryozoans as associates of other organisms (e.g. Rudman 2007; Chatterjee Dovgal 2020; Chatterjee et al. 2020), metazoan phylogeny (e.g. Giribet et al. 2013), biographies of historical figures who worked on bryozoans (e.g. Calder Brinkmann-Voss 2011; Calder 2015) and a catalogue of the fossil invertebrate taxa described by William Gabb (including 67 bryozoan species) (Groves Squires 2018). Of the 116 papers, 15 (13%) were open-access.

Bryozoa from the reefs off the Amazon River mouth: checklist, thirteen new species, and notes on their ecology and distribution.

The reef system off the Amazon River mouth extends from Amapá state to Maranhão state along the Brazilian Equatorial Margin, encompassing more than 10,000 km2 of rhodolith beds and high-relief hard structures on the outer shelf and upper slope. This unique hard bottom mosaic is remarkable for being influenced by the turbid and hyposaline plume from the world's largest river, and also for representing a connectivity corridor between the Caribbean and Brazil. Bryozoans were recently recognized as major reef builders in the Southwestern Atlantic, but their diversity off the Amazon River mouth remained unknown. Here, we report on recent collections obtained from 23 to 120 m depth in Northern Brazil. Sixty-five bryozoan taxa were characterized using scanning electron microscopy, including 57, five and three taxa of Cheilostomatida, Cyclostomatida and Ctenostomatida, respectively. Cribrilaria smitti and three genera (Cranosina, Glabrilaria and Thornelya) are new records for Brazil, and 13 new species are herein described: Antropora cruzeiro n. sp., Cranosina gilbertoi n. sp., Cribrilaria lateralis n. sp., Crisia brasiliensis n. sp., Glabrilaria antoniettae n. sp., Micropora amapaensis n. sp., Parasmittina amazonensis n. sp., Plesiocleidochasma arcuatum n. sp., Poricella bifurcata n. sp., Pourtalesella duoavicularia n. sp., Stephanollona domuspusilla n. sp., Therenia dianae n. sp., and Thornelya atlanticoensis n. sp. Our results highlight the biodiversity significance of the Amazon reefs and the need for more comprehensive sampling to clarify the role of bryozoans in modern turbid-zone reefs and rhodolith beds.

A broadly resolved molecular phylogeny of New Zealand cheilostome bryozoans as a framework for hypotheses of morphological evolution.

Larger molecular phylogenies based on ever more genes are becoming commonplace with the advent of cheaper and more streamlined sequencing and bioinformatics pipelines. However, many groups of inconspicuous but no less evolutionarily or ecologically important marine invertebrates are still neglected in the quest for understanding species- and higher-level phylogenetic relationships. Here, we alleviate this issue by presenting the molecular sequences of 165 cheilostome bryozoan species from New Zealand waters. New Zealand is our geographic region of choice as its cheilostome fauna is taxonomically, functionally and ecologically diverse, and better characterized than many other such faunas in the world. Using this most taxonomically broadly-sampled and statistically-supported cheilostome phylogeny comprising 214 species, when including previously published sequences, and 17 genes (2 nuclear and 15 mitochondrial) we tested several existing systematic hypotheses based solely on morphological observations. We find that lower taxonomic level hypotheses (species and genera) are robust while our inferred trees did not reflect current higher-level systematics (family and above), illustrating a general need for the rethinking of current hypotheses. To illustrate the utility of our new phylogeny, we reconstruct the evolutionary history of frontal shields (i.e., a calcified body-wall layer in ascus-bearing cheilostomes) and ask if its presence has any bearing on the diversification rates of cheilostomes.

Mitochondrial gene order of the freshwater bryozoan Cristatella mucedo retains ancestral lophotrochozoan features.

Bryozoans are aquatic colonial suspension-feeders abundant in many marine and freshwater benthic communities. At the same time, the phylum is under studied on both morphological and molecular levels, and its position on the metazoan tree of life is still disputed. Bryozoa include the exclusively marine Stenolaemata, predominantly marine Gymnolaemata and exclusively freshwater Phylactolaemata. Here we report the mitochondrial genome of the phylactolaemate bryozoan Cristatella mucedo. This species has the largest (21,008 bp) of all currently known bryozoan mitogenomes, containing a typical metazoan gene compendium as well as a number of non-coding regions, three of which are longer than 1500 bp. The trnS1/trnG/nad3 region is presumably duplicated in this species. Comparative analysis of the gene order in C. mucedo and another phylactolaemate bryozoan, Pectinatella magnifica, confirmed their close relationships, and revealed a stronger similarity to mitogenomes of phoronids and other lophotrochozoan species than to marine bryozoans, indicating the ancestral nature of their gene arrangement. We suggest that the ancestral gene order underwent substantial changes in different bryozoan cladesshowing mosaic distribution of conservative gene blocks regardless of their phylogenetic position. Altogether, our results support the early divergence of Phylactolaemata from the rest of Bryozoa.

Morphology of ctenostome bryozoans: 2. Haywardozoon pacificum, with implications of the phylogenetic position of the genus.

The genus Haywardozoon represent a little known genus of ctenostome bryozoans that has only been found in the deep-sea. It forms small, mostly uniserial colonies lacking polymorphs. Zooids have a conspicuous apertural closure mechanism consisting of a cuticular lower lip that closes the aperture. The systematic placement of the genus remains uncertain, detailed morphological studies that include soft-body morphological traits are missing. Consequently, this is the first study analyzing H. pacificum by means of histological serial sections and 3d-reconstruction. Zooids are ovoid and in some cases solitary, that is, showing no interconnected zooids. Most prominent is the large vestibular wall that can be more than half of the total length of the zooid. Its vestibular wall is particularly lined by a complex, multilayered and branched cuticle. A single pair of lateral parieto-diaphragmatic muscles is present. The polypide is small and comprises about 17 tentacles. The digestive tract is short, has an elongated cardia, a vestigial caecum and a vestibular anus. An ovipositor/intertentacular organ and several oligolecithal oocytes were detected. Several aspects of zooidal morphology, including the structure of the bilateral aperture, parieto-diaphragmatic muscles, general structure of the gut and the thick cuticle, clearly indicate an association to the ctenostome superfamily Alcyonidioidea. Therefore, we reject the previous placement into Hislopioidea and suggest a possible association to pherusellid ctenostomes. New reproductive characters show that H. pacificum is a broadcaster contrary to some other deep-sea forms that are brooding. RESEARCH HIGHLIGHT: Morphology of ctenostome bryozoans remain little investigated. This contribution is the second of a series of detailed morphological analyses of this understudied clade of bryozoans. The morphological investigation of Haywardozoon pacificum revealed numerous characters that show a closer relationship to Flustrellididrae rather than Hislopiidae as previously assumed.

The Phylum Bryozoa: From Biology to Biomedical Potential.

Less than one percent of marine natural products characterized since 1963 have been obtained from the phylum Bryozoa which, therefore, still represents a huge reservoir for the discovery of bioactive metabolites with its ~6000 described species. The current review is designed to highlight how bryozoans use sophisticated chemical defenses against their numerous predators and competitors, and which can be harbored for medicinal uses. This review collates all currently available chemoecological data about bryozoans and lists potential applications/benefits for human health. The core of the current review relates to the potential of bryozoan metabolites in human diseases with particular attention to viral, brain, and parasitic diseases. It additionally weighs the pros and cons of total syntheses of some bryozoan metabolites versus the synthesis of non-natural analogues, and explores the hopes put into the development of biotechnological approaches to provide sustainable amounts of bryozoan metabolites without harming the natural environment.

Key novelties in the evolution of the aquatic colonial phylum Bryozoa: evidence from soft body morphology.

Molecular techniques are currently the leading tools for reconstructing phylogenetic relationships, but our understanding of ancestral, plesiomorphic and apomorphic characters requires the study of the morphology of extant forms for testing these phylogenies and for reconstructing character evolution. This review highlights the potential of soft body morphology for inferring the evolution and phylogeny of the lophotrochozoan phylum Bryozoa. This colonial taxon comprises aquatic coelomate filter-feeders that dominate many benthic communities, both marine and freshwater. Despite having a similar bauplan, bryozoans are morphologically highly diverse and are represented by three major taxa: Phylactolaemata, Stenolaemata and Gymnolaemata. Recent molecular studies resulted in a comprehensive phylogenetic tree with the Phylactolaemata sister to the remaining two taxa, and Stenolaemata (Cyclostomata) sister to Gymnolaemata. We plotted data of soft tissue morphology onto this phylogeny in order to gain further insights into the origin of morphological novelties and character evolution in the phylum. All three larger clades have morphological apomorphies assignable to the latest molecular phylogeny. Stenolaemata (Cyclostomata) and Gymnolaemata were united as monophyletic Myolaemata because of the apomorphic myoepithelial and triradiate pharynx. One of the main evolutionary changes in bryozoans is a change from a body wall with two well-developed muscular layers and numerous retractor muscles in Phylactolaemata to a body wall with few specialized muscles and few retractors in the remaining bryozoans. Such a shift probably pre-dated a body wall calcification that evolved independently at least twice in Bryozoa and resulted in the evolution of various hydrostatic mechanisms for polypide protrusion. In Cyclostomata, body wall calcification was accompanied by a unique detachment of the peritoneum from the epidermis to form the hydrostatic membraneous sac. The digestive tract of the Myolaemata differs from the phylactolaemate condition by a distinct ciliated pylorus not present in phylactolaemates. All bryozoans have a mesodermal funiculus, which is duplicated in Gymnolaemata. A colonial system of integration (CSI) of additional, sometimes branching, funicular cords connecting neighbouring zooids via pores with pore-cell complexes evolved at least twice in Gymnolaemata. The nervous system in all bryozoans is subepithelial and concentrated at the lophophoral base and the tentacles. Tentacular nerves emerge intertentacularly in Phylactolaemata whereas they partially emanate directly from the cerebral ganglion or the circum-oral nerve ring in myolaemates. Overall, morphological evidence shows that ancestral forms were small, colonial coelomates with a muscular body wall and a U-shaped gut with ciliary tentacle crown, and were capable of asexual budding. Coloniality resulted in many novelties including the origin of zooidal polymorphism, an apomorphic landmark trait of the Myolaemata.

A genome-skimmed phylogeny of a widespread bryozoan family, Adeonidae.

BACKGROUND: Understanding the phylogenetic relationships among species is one of the main goals of systematic biology. Simultaneously, credible phylogenetic hypotheses are often the first requirement for unveiling the evolutionary history of traits and for modelling macroevolutionary processes. However, many non-model taxa have not yet been sequenced to an extent such that statistically well-supported molecular phylogenies can be constructed for these purposes. Here, we use a genome-skimming approach to extract sequence information for 15 mitochondrial and 2 ribosomal operon genes from the cheilostome bryozoan family, Adeonidae, Busk, 1884, whose current systematics is based purely on morphological traits. The members of the Adeonidae are, like all cheilostome bryozoans, benthic, colonial, marine organisms. Adeonids are also geographically widely-distributed, often locally common, and are sometimes important habitat-builders. RESULTS: We successfully genome-skimmed 35 adeonid colonies representing 6 genera (Adeona, Adeonellopsis, Bracebridgia, Adeonella, Laminopora and Cucullipora). We also contributed 16 new, circularised mitochondrial genomes to the eight previously published for cheilostome bryozoans. Using the aforementioned mitochondrial and ribosomal genes, we inferred the relationships among these 35 samples. Contrary to some previous suggestions, the Adeonidae is a robustly supported monophyletic clade. However, the genera Adeonella and Laminopora are in need of revision: Adeonella is polyphyletic and Laminopora paraphyletically forms a clade with some Adeonella species. Additionally, we assign a sequence clustering identity using cox1 barcoding region of 99% at the species and 83% at the genus level. CONCLUSIONS: We provide sequence data, obtained via genome-skimming, that greatly increases the resolution of the phylogenetic relationships within the adeonids. We present a highly-supported topology based on 17 genes and substantially increase availability of circularised cheilostome mitochondrial genomes, and highlight how we can extend our pipeline to other bryozoans.

Megabenthic communities of the Ligurian deep continental shelf and shelf break (NW Mediterranean Sea).

The Ligurian Sea is one of the most studied Mediterranean basins. Since the beginning of the last century, many research expeditions have characterized its benthic and pelagic fauna through scuba diving and trawl surveys. However, a large knowledge gap exists about the composition of benthic communities extending into the so-called mesophotic or twilight depth range, currently under intense pressure from commercial and recreational fishing. A series of visual surveys, carried out by means of remotely operated vehicles between 2012 and 2018, were conducted along the Ligurian deep continental shelf and shelf break, between 30 and 210 m depth, in order to characterize the main benthic biocoenoses dwelling at this depth range and to determine the most relevant environmental factors that explain their spatial distribution. Deep circalittoral communities of the Ligurian Sea were represented by a mixture of species belonging to the deepest extension of shallow-water habitats and deep circalittoral ones. Twelve major biocoenoses were identified, each one characterized by specific preferences in depth range, substrate type and seabed slope. Those biocoenoses included gorgonian and hydrozoan forests, dense keratose sponge grounds, Dendrophyllia cornigera gardens, bryozoan beds and soft-bottom meadows of sabellid polychaetes and soft-corals. Other less common aggregations included six forests of black corals and two populations of Paramuricea macrospina. A georeferenced database has been created in order to provide information to managers and stakeholders about the location of the identified communities and high-diversity areas, aiming to facilitate sustainable long-term conservation of the Ligurian benthic ecosystem.

Exotic species dominate marinas between the two most populated regions in the southwestern Atlantic Ocean.

Human occupation of coastal areas promotes the establishment of non-native species but information on bioinvasions is usually biased toward the Northern Hemisphere. We assessed non-native species' importance in sessile communities at six marinas along the most urbanized area of the Southwestern Atlantic coastline. We found 67 species, of which 19 are exotic. The most frequent species was the exotic polychaete Branchiomma luctuosum, while the most abundant was the exotic bryozoan Schizoporella errata that monopolized the substrata in three marinas. Along with S. errata, the exotic polychaete Hydroides elegans and ascidian Styela plicata dominated space in the three remaining marinas, while native species were in general rare. We show that communities associated with artificial substrata along this Brazilian urbanized area are dominated by exotic species and that using abundance data along with species identity can improve our understanding of the importance of exotic species for the dynamics of biological communities.

Cope's Rule in a modular organism: Directional evolution without an overarching macroevolutionary trend.

Cope's Rule describes increasing body size in evolutionary lineages through geological time. This pattern has been documented in unitary organisms but does it also apply to module size in colonial organisms? We address this question using 1169 cheilostome bryozoans ranging through the entire 150 million years of their evolutionary history. The temporal pattern evident in cheilostomes as a whole shows no overall change in zooid (module) size. However, individual subclades show size increases: within a genus, younger species often have larger zooids than older species. Analyses of (paleo)latitudinal shifts show that this pattern cannot be explained by latitudinal effects (Bergmann's Rule) coupled with younger species occupying higher latitudes than older species (an "out of the tropics" hypothesis). While it is plausible that size increase was linked to the advantages of large zooids in feeding, competition for trophic resources and living space, other proposed mechanisms for Cope's Rule in unitary organisms are either inapplicable to cheilostome zooid size or cannot be evaluated. Patterns and mechanisms in colonial organisms cannot and should not be extrapolated from the better-studied unitary organisms. And even if macroevolution simply comprises repeated rounds of microevolution, evolutionary processes occurring within lineages are not always detectable from macroevolutionary patterns.

Body cavities in bryozoans: Functional and phylogenetic implications.

Based on morphological evidence, Bryozoa together with Phoronida and Brachiopoda are traditionally combined in the group Lophophorata, although this view has been recently challenged by molecular studies. The core of the concept lies in the presence of the lophophore as well as the nature and arrangement of the body cavities. Bryozoa are the least known in this respect. Here, we focused on the fine structure of the body cavity in 12 bryozoan species: 6 gymnolaemates, 3 stenolaemates and 3 phylactolaemates. In gymnolaemates, the complete epithelial lining of the body cavity is restricted to the lophophore, gut walls, and tentacle sheath. By contrast, the cystid walls are composed only of the ectocyst-producing epidermis without a coelothelium, or an underlying extracellular matrix; only the storage cells and cells of the funicular system contact the epidermis. The nature of the main body cavity in gymnolaemates is unique and may be considered as a secondarily modified coelom. In cyclostomes, both the lophophoral and endosaccal cavities are completely lined with coelothelium, while the exosaccal cavity only has the epidermis along the cystid wall. In gymnolaemates, the lophophore and trunk cavities are divided by an incomplete septum and communicate through two pores. In cyclostomes, the septum has a similar location, but no openings. In Phylactolaemata, the body cavity is undivided: the lophophore and trunk coeloms merge at the bases of the lophophore arms, the epistome cavity joins the trunk, and the forked canal opens into the arm coelom. The coelomic lining of the body is complete except for the epistome, lophophoral arms, and the basal portions of the tentacles, where the cells do not interlock perfectly (this design probably facilitates the ammonia excretion). The observed partitioning of the body cavity in bryozoans differs from that in phoronids and brachiopods, and contradicts the Lophophorata concept.

Reconstructing the muscular ground pattern of phylactolaemate bryozoans: first data from gelatinous representatives.

BACKGROUND: Phylactolaemata is commonly regarded the earliest branch within Bryozoa and thus the sister group to the other bryozoan taxa, Cyclostomata and Gymnolaemata. Therefore, the taxon is important for the reconstruction of the bryozoan morphological ground pattern. In this study the myoanatomy of Pectinatella magnifica, Cristatella mucedo and Hyalinella punctata was analysed by means of histology, f-actin staining and confocal laser-scanning microscopy in order to fill gaps in knowledge concerning the myoanatomy of Phylactolaemata. RESULTS: The retractor muscles and muscles of the aperture, gut, body wall, tentacle sheath, lophophore constitute the most prominent muscular subsets in these species. The lophophore shows longitudinal muscle bands in the tentacles, lophophoral arm muscles, epistome musculature and hitherto undescribed muscles of the ring canal. In general the muscular system of the three species is very similar with differences mainly in the body wall, tentacle sheath and epistome. The body wall contains an orthogonal grid of musculature. The epistome exhibits either a muscular meshwork in the epistomal wall or muscle fibers traversing the epistomal cavity. The whole tentacle sheath possesses a regular mesh of muscles in Pectinatella and Cristatella, whereas circular muscles are limited to the tentacle sheath base in Hyalinella. CONCLUSION: This study is the first to describe muscles of the ring canal and contributes to reconstructing muscular features for the last common ancestor of all bryozoans. The data available suggest that two longitudinal muscle bands in the tentacles, as well as retractor muscles and longitudinal and circular muscles in the tentacle sheath, were present in the last common bryozoan ancestor. Comparisons among bryozoans shows that several apomorphies are present in the myoanatomy of each class- level taxon such as the epistomal musculature and musculature of the lophophoral arms in phylactolaemates, annular muscles in cyclostomes and parietal muscles in gymnolaemates.

A big data approach to macrofaunal baseline assessment, monitoring and sustainable exploitation of the seabed.

In this study we produce a standardised dataset for benthic macrofauna and sediments through integration of data (33,198 samples) from 777 grab surveys. The resulting dataset is used to identify spatial and temporal patterns in faunal distribution around the UK, and the role of sediment composition and other explanatory variables in determining such patterns. We show how insight into natural variability afforded by the dataset can be used to improve the sustainability of activities which affect sediment composition, by identifying conditions which should remain favourable for faunal recolonisation. Other big data applications and uses of the dataset are discussed.