Rediscovering the unusual, solitary bryozoan Monobryozoon ambulans Remane, 1936: first molecular and new morphological data clarify its phylogenetic position.

BACKGROUND: One of the most peculiar groups of the mostly colonial phylum Bryozoa is the taxon Monobryozoon, whose name already implies non-colonial members of the phylum. Its peculiarity and highly unusual lifestyle as a meiobenthic clade living on sand grains has fascinated many biologists. In particular its systematic relationship to other bryozoans remains a mystery. Despite numerous searches for M. ambulans in its type locality Helgoland, a locality with a long-lasting marine station and tradition of numerous courses and workshops, it has never been reencountered until today. Here we report the first observations of this almost mythical species, Monobryozoon ambulans. RESULTS: For the first time since 1938, we present new modern, morphological analyses of this species as well as the first ever molecular data. Our detailed morphological analysis confirms most previous descriptions, but also ascertains the presence of special ambulatory polymorphic zooids. We consider these as bud anlagen that ultimately consecutively separate from the animal rendering it pseudo-colonial. The remaining morphological data show strong ties to alcyonidioidean ctenostome bryozoans. Our morphological data is in accordance with the phylogenomic analysis, which clusters it with species of Alcyonidium as a sister group to multiporate ctenostomes. Divergence time estimation and ancestral state reconstruction recover the solitary state of M. ambulans as a derived character that probably evolved in the Late Cretaceous. In this study, we also provide the entire mitogenome of M. ambulans, which-despite the momentary lack of comparable data-provides important data of a unique and rare species for comparative aspects in the future. CONCLUSIONS: We were able to provide first sequence data and modern morphological data for the unique bryozoan, M. ambulans, which are both supporting an alcyonidioidean relationship within ctenostome bryozoans.

Morphology of ctenostome bryozoans: 7. Hislopia, Echinella and Timwoodiellina.

Ctenostome bryozoans are a small group of gymnolaemates comprising less than 400 recent species. They are paraphyletic and ctenostome-grade ancestors gave rise to Cheilostomata, the most dominant and speciose taxon of Bryozoa in the present day. Investigations into ctenostomes are important for reconstructing character evolution among Gymnolaemata. As a continuation of studies on a morphological series of ctenostome bryozoans, we herein investigate six species of hislopiids, a small clade of three genera occurring in freshwater habitats. The general morphology of all species is similar in having primarily uniserial chains of encrusting zooids, which are mostly oval to ellipsoid and have a flattened frontobasal axis. Hislopia prolixa and Echinella placoides often have more slender zooids with a higher frontobasal axis. Apertures of hislopiids are quadrangular, lined by a thickened cuticle. Apertural spines are present in various lengths in E. placoides, Hislopia lacustris and Hislopia corderoi. The remaining cuticle is rather thin except at lateral areas, close to the pore-plates which are prominent in hislopiids because of abundant special and limiting cells. All species except H. corderoi and Timwoodiellina natans have a prominent collar obstructing the vestibulum, whereas the latter two species instead have an 'external collar' as cuticular, outer folds projecting over the aperture. Hislopiid lophophores carry eight, or more commonly 12-18 tentacles. The digestive tract is distinguished by an often highly elongated esophagus and/or cardia, with the latter always having a prominent bulbous part in the form of a proventriculus-or gizzard in E. placoides. The caecum is extensive in all species. In Hislopia the intestine is characteristically two-chambered with a proximal and distal part before entering an anal tube of various length. The latter is present in all species except T. natans and terminates in mid-lophophoral area. Oocytes in E. placoides are large and macrolecithal indicating brooding and the production of lecithotrophic larvae. Hislopia species produce small, oligolecithal ones, which suggests zygote spawning and planktotrophy. In general, the morphology is similar among the different hislopiids with characters of the gut aiding in delineating the genera Echinella and Timwoodiellina.

Multiple evolutionary transitions of reproductive strategies in a phylum of aquatic colonial invertebrates.

Parental care is considered crucial for the enhanced survival of offspring and evolutionary success of many metazoan groups. Most bryozoans incubate their young in brood chambers or intracoelomically. Based on the drastic morphological differences in incubation chambers across members of the order Cheilostomatida (class Gymnolaemata), multiple origins of incubation were predicted in this group. This hypothesis was tested by constructing a molecular phylogeny based on mitogenome data and nuclear rRNA genes 18S and 28S with the most complete sampling of taxa with various incubation devices to date. Ancestral character estimation suggested that distinct types of brood chambers evolved at least 10 times in Cheilostomatida. In Eucratea loricata and Aetea spp. brooding evolved unambiguously from a zygote-spawning ancestral state, as it probably did in Tendra zostericola, Neocheilostomata, and 'Carbasea' indivisa. In two further instances, brooders with different incubation chamber types, skeletal and non-skeletal, formed clades (Scruparia spp., Leiosalpinx australis) and (Catenicula corbulifera (Steginoporella spp. (Labioporella spp., Thalamoporella californica))), each also probably evolved from a zygote-spawning ancestral state. The modular nature of bryozoans probably contributed to the evolution of such a diverse array of embryonic incubation chambers, which included complex constructions made of polymorphic heterozooids, and maternal zooidal invaginations and outgrowths.

Records of the non-native alga Acanthophoraspicifera (Rhodophyta) and their colonial epibionts in La Paz Bay, Gulf of California.

Acanthophoraspicifera, a red alga considered an alien species, was discovered for the first time on the Pacific coast of Mexico in 2006 from a locality inside La Paz Bay, Gulf of California. Since then, more records have shown its presence, 17 localities having been added up to 2015. A two-year field study (2020-2022) visiting 31 sites along the coast of La Paz Bay, complemented with data from literature and citizen science, resulted in a database of 709 entries that spans the data from 2004 to 2023. These data showed a distribution that goes from Punta Coyote, close to Boca Grande, the northern entrance to the Bay to Playa Tecolote in the south, more than 100 km of coastline, including Espiritu Santo Archipelago, an area considered a natural reserve since 2007. Anthropogenic activity and environmental variables did not present statistical differences that explain A.spicifera spreading. It represents a naturalised alien species without evidence of a negative impact. Still, it soon could acquire the status of invasive species together with its epibionts Bryozoa and Hydrozoa detected in this study.

Spatial competition in a global disturbance minimum; the seabed under an Antarctic ice shelf.

The marine habitat beneath Antarctica's ice shelves spans ∼1.6 million km2, and life in this vast and extreme environment is among Earth's least accessible, least disturbed and least known, yet likely to be impacted by climate-forced warming and environmental change. Although competition among biota is a fundamental structuring force of ecological communities, hence ecosystem functions and services, nothing was known of competition for resources under ice shelves, until this study. Boreholes drilled through a âˆ¼ 200 m thick ice shelf enabled collections of novel sub-ice-shelf seabed sediment which contained fragments of biogenic substrata rich in encrusting (lithophilic) macrobenthos, principally bryozoans - a globally-ubiquitous phylum sensitive to environmental change. Analysis of sub-glacial biogenic substrata, by stereo microscopy, provided first evidence of spatial contest competition, enabling generation of a new range of competition measures for the sub-ice-shelf benthic space. Measures were compared with those of global open-water datasets traversing polar, temperate and tropical latitudes (and encompassing both hemispheres). Spatial competition in sub-ice-shelf samples was found to be higher in intensity and severity than all other global means. The likelihood of sub-ice-shelf competition being intraspecific was three times lower than for open-sea polar continental shelf areas, and competition complexity, in terms of the number of different types of competitor pairings, was two-fold higher. As posited for an enduring disturbance minimum, a specific bryozoan clade was especially competitively dominant in sub-ice-shelf samples compared with both contemporary and fossil assemblage records. Overall, spatial competition under an Antarctic ice shelf, as characterised by bryozoan interactions, was strikingly different from that of open-sea polar continental shelf sites, and more closely resembled tropical and temperate latitudes. This study represents the first analysis of sub-ice-shelf macrobenthic spatial competition and provides a new ecological baseline for exploring, monitoring and comparing ecosystem response to environmental change in a warming world.

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.

The genome sequence of the sea mat, Membranipora membranacea (Linnaeus, 1767).

We present a genome assembly from an adult colony of Membranipora membranacea (the sea mat; Bryozoa; Gymnolaemata; Cheilostomatida; Membraniporidae). The genome sequence is 339 megabases in span. Most of the assembly (99.95%) is scaffolded into 11 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 14.7 kilobases in length.

Shallow-Water Bryozoan Communities in a Glacier Fjord of West Svalbard, Norway: Species Composition and Effects of Environmental Factors.

Despite significant research efforts focused on benthic assemblages in West Spitsbergen, there is a lack of knowledge regarding the shallow water bryozoan communities in Grønfjorden, a glacier fjord belonging to the Isfjorden system, Norway. Here, we studied species composition, richness, distribution, and biomass of bryozoans in the intertidal and upper subtidal zones of Grønfjorden in summer. We found 62 bryozoan species, among which Celleporella hyalina (Linnaeus, 1767), Harmeria scutulata (Busk, 1855), and Tegella arctica (d'Orbigny, 1853) were most prevalent while the highest contributions to the total biomass were registered for Eucratea loricata (d'Orbigny, 1853), Tricellaria gracilis (Van Beneden, 1848), Turbicellepora incrassata (Lamarck, 1816), and Tricellaria ternata (Ellis and Solander, 1786). Alpha-diversity varied from 1 to 50 averaging 15.1 ± 2.6 species. Bryozoan biomass ranged from 0.008 to 10.758 g m-2 with a mean value of 2.67 g m-2 being lower than in the central and northern parts of the Barents Sea. For the first time, we registered the presence of the circumpolar bryozoan Amathia arctica in Svalbard waters probably as a result of stronger advection of Atlantic water into the fjord. Cluster analysis revealed two groups, mainly composed of stations in colder and warmer waters. A relatively high proportion of outlying stations reflected habitat heterogeneity in Grønfjorden. Redundancy analysis indicated that bryozoan diversity and biomass were strongly negatively associated with temperature. A positive relationship was found between bryozoan biomass and the proportional contribution of macrophytes to a pool of substrates. Our study provides a reference point for further monitoring of changing marine ecosystems at high latitudes.

Promising Antiparasitic Natural and Synthetic Products from Marine Invertebrates and Microorganisms.

Parasitic diseases still threaten human health. At present, a number of parasites have developed drug resistance, and it is urgent to find new and effective antiparasitic drugs. As a rich source of biological compounds, marine natural products have been increasingly screened as candidates for developing new antiparasitic drugs. The literature related to the study of the antigenic animal activity of marine natural compounds from invertebrates and microorganisms was selected to summarize the research progress of marine compounds and the structure-activity relationship of these compounds in the past five years and to explore the possible sources of potential antiparasitic drugs for parasite treatment.

Unusual lophophore innervation in ctenostome Flustrellidra hispida (Bryozoa).

Since ctenostomes are traditionally regarded as an ancestral clade to some other bryozoan groups, the study of additional species may help to clarify questions on bryozoan evolution and phylogeny. One of these questions is the bryozoan lophophore evolution: whether it occurred through simplification or complication. The morphology and innervation of the ctenostome Flustrellidra hispida (Fabricius, 1780) lophophore have been studied with electron microscopy and immunocytochemistry with confocal laser scanning microscopy. Lophophore nervous system of F. hispida consists of several main nerve elements: cerebral ganglion, circumoral nerve ring, and the outer nerve ring. Serotonin-like immunoreactive perikarya, which connect with the circumoral nerve ring, bear the cilium that directs to the abfrontal side of the lophophore and extends between tentacle bases. The circumoral nerve ring gives rise to the intertentacular and frontal tentacle nerves. The outer nerve ring gives rise to the abfrontal neurites, which connect to the outer groups of perikarya and contribute to the formation of the abfrontal tentacle nerve. The outer nerve ring has been described before in other bryozoans, but it never contributes to the innervation of tentacles. The presence of the outer nerve ring participating in the innervation of tentacles makes the F. hispida lophophore nervous system particularly similar to the lophophore nervous system of phoronids. This similarity allows to suggest that organization of the F. hispida lophophore nervous system may reflect the ancestral state for all bryozoans. The possible scenario of evolutionary transformation of the lophophore nervous system within bryozoans is suggested.

Phylogenomics reveals deep relationships and diversification within phylactolaemate bryozoans.

Bryozoans are mostly sessile colonial invertebrates that inhabit all kinds of aquatic ecosystems. Extant bryozoan species fall into two clades with one of them, Phylactolaemata, being the only exclusively freshwater clade. Phylogenetic relationships within the class Phylactolaemata have long been controversial owing to their limited distinguishable characteristics that reflect evolutionary relationships. Here, we present the first phylogenomic analysis of Phylactolaemata using transcriptomic data combined with dense taxon sampling of six families to better resolve the interrelationships and to estimate divergence time. Using maximum-likelihood and Bayesian inference approaches, we recovered a robust phylogeny for Phylactolaemata in which the interfamilial relationships are fully resolved. We show Stephanellidae is the sister taxon of all other phylactolaemates and confirm that Lophopodidae represents the second offshoot within the phylactolaemate tree. Plumatella fruticosa clearly falls outside Plumatellidae as previous investigations have suggested, and instead clusters with Pectinatellidae and Cristatellidae as the sister taxon of Fredericellidae. Our results demonstrate that cryptic speciation is very likely in F. sultana and in two species of Plumatella (P. repens and P. casmiana). Divergence time estimates show that Phylactolaemata appeared at the end of the Ediacaran and started to diverge in the Silurian, although confidence intervals were large for most nodes. The radiation of most extant phylactolaemate families occurred mainly in the Palaeogene and Neogene highlighting post-extinction diversification.

Changing allometric relationships among fossil and Recent populations in two colonial species.

Allometry is vital for understanding the mechanisms underlying phenotypic evolution. Despite a large body of literature on allometry, studies based on fossil time series are limited for solitary organisms and nonexistent for colonial organisms. Allometric relationships have been found to be relatively constant across Recent populations of the same species, separated by space, but variable among fossil populations separated by thousands of years. How stable are allometric relationships at the module level for colonial organisms? We address this question using two extant species of the cheilostome bryozoan Microporella with fossil records spanning the Pleistocene of New Zealand. We investigate size covariation between feeding modules and three traits with separate functions (reproductive, resource uptake, and defense). We found that within-population (static) allometry can change on timescales of at least 0.1 million years. These within-population relationships do not consistently predict overintraspecific evolutionary allometry, which in turn does not predict those estimated at the genus level. Different functional traits are constrained to different extents by module size with defensive traits being the least constrained and most evolvable, compared with reproductive and resource uptake traits. Our study highlights the potential of colonial organisms in understanding the constraints and drivers of long-term phenotypic change.

Enhancing georeferenced biodiversity inventories: automated information extraction from literature records reveal the gaps.

We use natural language processing (NLP) to retrieve location data for cheilostome bryozoan species (text-mined occurrences (TMO)) in an automated procedure. We compare these results with data combined from two major public databases (DB): the Ocean Biodiversity Information System (OBIS), and the Global Biodiversity Information Facility (GBIF). Using DB and TMO data separately and in combination, we present latitudinal species richness curves using standard estimators (Chao2 and the Jackknife) and range-through approaches. Our combined DB and TMO species richness curves quantitatively document a bimodal global latitudinal diversity gradient for extant cheilostomes for the first time, with peaks in the temperate zones. A total of 79% of the georeferenced species we retrieved from TMO (N = 1,408) and DB (N = 4,549) are non-overlapping. Despite clear indications that global location data compiled for cheilostomes should be improved with concerted effort, our study supports the view that many marine latitudinal species richness patterns deviate from the canonical latitudinal diversity gradient (LDG). Moreover, combining online biodiversity databases with automated information retrieval from the published literature is a promising avenue for expanding taxon-location datasets.

Bryozoans from the Early Ordovician Fenhsiang Formation (Tremadocian) of South China and the early diversification of the phylum.

Although phosphatized bryozoans have been described recently from the early Cambrian, the first unequivocal bryozoan fossils with hard skeletons are known from the Ordovician. Recent discoveries of bryozoans in the early Ordovician (Tremadocian) of South China have greatly expanded our understanding of the diversification of these colonial lophophorates. In particular, the Fenhsiang Formation of Late Tremadocian age (Migneintian) in Hubei Province is proving to be particularly rich in bryozoans. Here we record 24 species, including several yet to be formally described, belonging to 18 genera and four palaeostomate suborders (Esthonioporata, Cystoporata, Trepostomata, and Cryptostomata). Bryozoan diversity in the Fenhsiang Formation matches levels more typical of younger faunas of Middle Ordovician age. The presence of diverse and morphologically disparate taxa close to the base of the Ordovician suggests rapid diversification following the first appearance of bryozoans with calcified skeletons, and/or the existence of as yet unknown biomineralized bryozoans in the Cambrian.

Environmental Drivers of an Intertidal Bryozoan Community in the Barents Sea: A Case Study.

There is a lack of knowledge regarding the modern status of intertidal bryozoan communities in the coastal Barents Sea. Here, we studied species composition, richness, and biomass of bryozoans in Yarnyshnaya and Dalnezelenetskaya Bays, both located in the eastern part of the Kola Peninsula (Barents Sea), in summer. Species composition and biodiversity were consistent with previous research but the record of the ctenostome bryozoan Walkeriauva is the first for the region indicating eastward range expansion of this species associated with climate forcing in the Arctic. Mean biomass was relatively low accounting for 2.25 ± 0.95 g·m-2. The most common species were Eucratea loricata, Harmeria scutulata, Crisia eburnea, and Cribrilina cryptooecium averaging 96% of the total biomass. Cluster analysis delineated two distinct groups of stations, one with true marine conditions and another with brackish water conditions. Redundancy analysis revealed that bryozoan diversity was strongly associated with salinity fluctuations being extremely low at brackish water sites. In contrast, water temperature was found to be a significant contributor to biomass with the lowest values found at warmer waters probably owing to the predominance of Boreo-Arctic species which prefer lower-temperatures. Other hydrological variables (dissolved organic matter, silicates, and oxygen) were consistent with usual summer values and had no significant effects on the bryozoan assemblages. Our study provides a reference point for further biodiversity studies in changing marine ecosystems of the Arctic region.

Bryozoan carbonate skeletal geochemical composition in the White Sea compared with neighbouring seas.

A fundamental question underlying skeletal mineral secretion in marine invertebrates is the extent to which the physico-chemical parameters of seawater (e.g., salinity, temperature) and animal physiology influence their skeletal mineralogy and chemistry. Groups with more complex mineralogies, such as bryozoans, have the ability to actively control their own skeletal composition in response to environmental conditions and could be considered indicators of global environmental change. Thus, this study aims to reveal how the unique environmental conditions of low salinity (circa 24-26), prominent seasonality and semi-isolation of the White Sea (WS) subarctic region caused by the last glaciation (12,000 ya) affect the carbonate skeletal geochemical composition of bryozoans. X-ray diffraction analysis of 27 bryozoan taxa (92 specimens) revealed a completely monomineral calcite composition of skeletons with a mean value of 6.9 ± 1.8 mol% MgCO3 and moderate variability at the species and family levels. Most specimens (43.5%) precipitated skeletal magnesium within the range of 7-8 mol% MgCO3. Regional analysis of the mineralogical profile of the White Sea bryozoans shows that they differ statistically from bryozoan species living in the neighbouring Arctic and temperate Scotland regions in terms of magnesium content in calcite (approximately 7 mol% MgCO3 in the White Sea versus 5 mol% MgCO3 in other regions). We suggest that the effect of low salinity on magnesium content was compensated by relatively high summer temperature causing rapid growth and calcification and possibly resulted in the increased Mg contents in the White Sea (WS) bryozoans. However, on a local scale (between sampling locations), the influence of temperature and salinity could be excluded as a source of observed intraspecific variability. The concentration of MgCO3 in skeletons of the studied bryozoans is controlled by other environmental variables or is species-specific and depends on the physiological processes of the organisms.

When fossil clades 'compete': local dominance, global diversification dynamics and causation.

Examining the supposition that local-scale competition drives macroevolutionary patterns has become a familiar goal in fossil biodiversity studies. However, it is an elusive goal, hampered by inadequate confirmation of ecological equivalence and interactive processes between clades, patchy sampling, few comparative analyses of local species assemblages over long geological intervals, and a dearth of appropriate statistical tools. We address these concerns by reevaluating one of the classic examples of clade displacement in the fossil record, in which cheilostome bryozoans surpass the once dominant cyclostomes. Here, we analyse a newly expanded and vetted compilation of 40 190 fossil species occurrences to estimate cheilostome and cyclostome patterns of species proportions within assemblages, global genus richness and genus origination and extinction rates while accounting for sampling. Comparison of time-series models using linear stochastic differential equations suggests that inter-clade genus origination and extinction rates are causally linked to each other in a complex feedback relationship rather than by simple correlations or unidirectional relationships, and that these rates are not causally linked to changing within-assemblage proportions of cheilostome versus cyclostome species.

Polypide anatomy of hornerid bryozoans (Stenolaemata: Cyclostomatida).

Bryozoans are small colonial coelomates whose colonies are made of individual modules (zooids). Like most coelomate animals, bryozoans have a characteristic body wall composition, including an epidermis, an extracellular matrix (ECM) and a coelothelium, all pressed together. The order Cyclostomatida, however, presents the most striking deviation, in which the ECM and the corresponding coelothelium underlying major parts of the skeletal wall epidermis are detached to form an independent membranous sac. It forms a separate, much smaller compartment, suspended in the zooid body cavity and working as an important element of the cyclostome lophophore protrusion mechanism. The polypide anatomy and ultrastructure of this group is best known from studies of one family, the Crisiidae (Articulata). Here, we examined four species from the phylogenetically and ecologically contrasting family Horneridae (Cancellata) from New Zealand, and provide the first detailed ultrastructural description of the hornerid polypide, including tentacles, mouth region, digestive system and the funiculus. We were able to trace continuity and transitions of cell and ECM layers throughout the whole polypide. In addition, we identified that the funiculus is a lumen-free ECM cord with two associated muscles, disconnected from interzooidal pores. Except for funicular core composition, the polypide anatomy of hornerids agrees well with the general cyclostomate body plan.

Developmental Process of a Heterozooid: Avicularium Formation in a Bryozoan, Bugulina californica.

In bryozoans (phylum Bryozoa), representative colonial animals mostly found in marine environments, some species possess different types of individuals (heterozooids) specialized in different functions such as defense or structural support for their colonies. Among them, the best-known heterozooids are the avicularia, known to function as defenders. The differentiation processes of heterozooids, including avicularia, should be important keys to understand the evolutionary significance of bryozoans. However, the developmental process of avicularium formation remains to be fully understood. In this study, therefore, in order to understand the detailed developmental process and timing of avicularium formation, extensive observations were carried out in a bryozoan species, Bugulina californica (Cheilostomata, Bugulidae), that possesses adventitious avicularia, by performing stereomicroscopy on live materials, in addition to scanning electron microscopy and histological observations. The whole process can be divided into seven stages based on developmental events. Especially notably, at the earlier stages, there are three major budding events that produce proliferating cell masses corresponding to primordial tissues: (1) budding of the peduncle cushion at the outer margin of the distal part of a young autozooid, (2) budding of the head-part primordium from the peduncle cushion, and (3) budding of the polypide inside the head part. Experimental control of temperature showed that 20°C would be the best to maintain B. californica colonies.

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.