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Andrej Ernst - One of the best experts on this subject based on the ideXlab platform.
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Richness of Famennian-Tournaisian (late Devonian-early Carboniferous) Bryozoans in shallow areas of Palaeotethys and Palaeoasian oceans
Palaeobiodiversity and Palaeoenvironments, 2021Co-Authors: Zoya Tolokonnikova, Andrej ErnstAbstract:Based on the analysis of data on Bryozoan localities in territory of modern Eurasia, changes of the Bryozoan richness were calculated in detail for six time slices in the interval from the early Famennian to the late Tournaisian. Highest extinction tempo was observed for the latest Famennian, apparently linked to the Hangenberg Event. However, in the richness of Bryozoans during the late-latest Famennian, an abrupt increase in the origination tempo is observed, as well as a slight decrease in the total Bryozoan richness at the Devonian-Carboniferous transition. Origination of abundant narrowly specialised Bryozoan genera in the orders Trepostomata and Cryptostomata at the end of the Devonian and in the beginning of the Carboniferous was caused by the combined influence of extrinsic and intrinsic factors. An observed increase in the morphological specialisation of Bryozoans during the Late Devonian and early Carboniferous coincides with patterns observed in other benthic organisms such as brachiopods and rugose corals. These patterns can be explained by vacation of ecological niches and changes in the structure of the marine biota in the aftermath of the Hangenberg Event.
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SYMBIOSIS OF CORNULITIDS AND BryozoanS IN THE LATE ORDOVICIAN OF ESTONIA (BALTICA)
PALAIOS, 2018Co-Authors: Olev Vinn, Andrej Ernst, Ursula ToomAbstract:Three species of trepostome Bryozoans formed syn vivo associations with the Cornulites in the Late Ordovician of Estonia. Cornulites sp. and Mesotrypa excentrica presumably formed a true symbiotic association. This is the first known case of symbiosis between cornulitids and Bryozoans. It is not known whether this symbiotic association was obligatory of facultative for the cornulitid, but it was facultative for the Bryozoan. In this association cornulitids may have competed for the food with Bryozoans and the association may have been parasitic. The remaining associations between cornulitids and Bryozoans were accidental. Most common skeletonized endobionts of the Ordovician Bryozoans were not cornulitids, but conulariids and rugosans.
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a Bryozoan fauna from the mississippian tournaisian and visean of belgium
Geobios, 2017Co-Authors: Andrej Ernst, Zoya Tolokonnikova, Edouard Poty, Bernard MottequinAbstract:Eleven Bryozoan species are described from the Mississippian of southern Belgium, including one new species, Atactotoechus vaulxensis, and one species left in open nomenclature (Stenophragmidium sp.). From this fauna, four species are restricted to the Tournaisian stage, and seven occur in the Visean. The fauna is mainly small-sized, represented by branched ramose, encrusting and reticulate growth forms. Bryozoans in the Mississippian of southern Belgium preferred deeper, clay-rich environments. The identified Bryozoan species are mainly distributed within the European basin, with some similarities with the Mississippian faunas of Siberia and Kazakhstan.
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earliest symbiotic rugosans in cystoporate Bryozoan ceramopora intercellata bassler 1911 from late ordovician of estonia baltica
Palaeogeography Palaeoclimatology Palaeoecology, 2016Co-Authors: Olev Vinn, Andrej Ernst, Ursula ToomAbstract:Abstract The earliest known endobiotic rugose corals are recorded in the Katian of Estonia. Multiple rugosans were partially embedded in colonies of the cystoporate Bryozoan Ceramopora intercellata Bassler, 1911, leaving only their apertures free on the Bryozoan growth surface. Bodophyllum sp. and Lambelasma sp. are rugosans that formed a symbiotic association with C. intercellata which may have been mutualistic. Rugosans presumably benefitted from growth within the stable substrate provided by the Bryozoan, while Bryozoans presumably benefitted by protection against some types of predators. Symbiosis between rugosans and the Bryozoan Ceramopora intercellata was most likely facultative.
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exceptional Bryozoan assemblage of a microbial dominated reef from the early wenlock of gotland sweden
Gff, 2015Co-Authors: Andrej Ernst, Axel Munnecke, Irina OswaldAbstract:Eleven Bryozoan species were described from Nors Stenbrott (Gotland, Sweden), represented by six trepostomes, four cystoporates and one fenestrate. Three genera with three species are new: two cystoporates Acantholunaria expansa gen. n. sp. n. and Curviporamonostylata gen. n. sp. n., and a trepostome Stellatotrypa hirsuta gen. n. sp. n. Two trepostome species are new: Leptotrypa perforata sp. n. and Leptotrypa enodis sp. n. The described Bryozoan fauna is dominated by thin encrusting taxa which are involved in intensive interactions with calcimicrobes in Bryozoan-microbial crusts in the reef. The Bryozoan-microbial crusts (bryoliths) show certain sequences by microbes, encrusting Bryozoans and tabulate corals. Multiple self-overgrowth of Bryozoans occurs frequently and is interpreted as a defensive tactic against microbial fouling. Bryozoans avoid vicinity to tabulate corals, apparently due to strong competition for substrate. The Bryozoan fauna from Nors Stenbrott is highly endemic, only two species are ...
Paul D. Taylor - One of the best experts on this subject based on the ideXlab platform.
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carbonate mineralogy of a tropical Bryozoan biota and its vulnerability to ocean acidification
Marine Biology Research, 2016Co-Authors: Paul D. Taylor, Aileen Tan Shauhwai, Anatoliy B Kudryavstev, William J SchopfAbstract:ABSTRACTDecreasing pH levels in the world’s oceans are widely recognized as a threat to marine life. Bryozoans are among several phyla that produce calcium carbonate skeletons potentially affected by ocean acidification (OA). Depending on species, Bryozoan skeletons can consist of calcite, aragonite or have a bimineralic combination of these two minerals. Aragonite is generally more soluble in seawater than calcite, making aragonitic species more vulnerable to OA. Here, for the first time we use Raman spectroscopy to determine the mineral composition of a tropical Bryozoan biota. Compared with Bryozoan biotas from higher latitudes in which calcite predominates, aragonite was found to occur in a much higher proportion of the 22 cheilostome Bryozoan species collected from the shorelines of Penang and Langkawi in Malaysia, where 46% of species are calcitic, 41% aragonitic and 13% bimineralic. All but one of the aragonitic or bimineralic species belong to the ascophorans, whereas calcitic skeletons characteri...
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the oldest known Bryozoan prophyllodictya cryptostomata from the lower tremadocian lower ordovician of liujiachang south western hubei central china
Palaeontology, 2015Co-Authors: Paul D. Taylor, Fengsheng Xia, Renbin ZhanAbstract:A new cryptostome Bryozoan, Prophyllodictya simplex sp. nov., is described from the Nantzinkuan Formation (Lower Ordovician, lower Tremadoc) of Liujiachang, central China. This antedates the previously oldest known Bryozoan by several million years. Colony morphology and the phylogenetic position of Prophyllodictya within Cryptostomata are explored. Phylogenetic analysis suggests that Cryptostomata (except Prophyllodictya) can be divided into two major groups, and that Prophyllodictya occupies a basal position in the cryptostome tree, which accords with its simple morphology and antiquity. A close relationship is evident between Bryozoans from the South China palaeoplate and those from Baltica.
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Phylogeny and diversification of Bryozoans
Palaeontology, 2015Co-Authors: Paul D. Taylor, Andrea WaeschenbachAbstract:Although only a small fraction of the estimated 6000 extant Bryozoan species has been analysed in a molecular phylogenetic context, the resultant trees have increased our understanding of the interrelationships between major Bryozoan groups, as well as between Bryozoans and other metazoan phyla. Molecular systematic analyses have failed to recover the Lophophorata as a monophyletic clade until recently, when phylogenomic data placed the Brachiopoda as sister to a clade formed by Phoronida + Bryozoa. Among Bryozoans, class Phylactolaemata has been shown to be the sister group of Gymnolaemata + Stenolaemata, corroborating earlier anatomical inferences. Despite persistent claims, there are no unequivocal Bryozoans of Cambrian age: the oldest Bryozoans are stenolaemates from the Tremadocian of China. Stenolaemates underwent a major radiation during the Ordovician, but the relationships between the six orders involved are poorly understood, mostly because the simple and plastic skeletons of stenolaemates make phylogenetic analyses difficult. Bryozoans were hard-hit by the mass extinction/s in the late Permian and it was not until the Middle Jurassic that they began to rediversify, initially through the cyclostome stenolaemates. The most successful post-Palaeozoic order (Cheilostomata) evolved a calcareous skeleton de novo from a soft-bodied ancestor in the Late Jurassic, maintained a low diversity until the mid-Cretaceous and then began to radiate explosively. A remarkable range of morphological structures in the form of highly modified zooidal polymorphs, or non-zooidal or intrazooidal modular elements, is postulated to have evolved repeatedly in this group. Crucially, many of these structures have been linked to micropredator protection and can be interpreted as key traits linked to the diversification of cheilostomes.
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Biomineralization in Bryozoans: present, past and future
Biological reviews of the Cambridge Philosophical Society, 2014Co-Authors: Paul D. Taylor, Chiara Lombardi, Silvia CocitoAbstract:Many animal phyla have the physiological ability to produce biomineralized skeletons with functional roles that have been shaped by natural selection for more than 500 million years. Among these are Bryozoans, a moderately diverse phylum of aquatic invertebrates with a rich fossil record and importance today as bioconstructors in some shallow-water marine habitats. Biomineralizational patterns and, especially, processes are poorly understood in Bryozoans but are conventionally believed to be similar to those of the related lophotrochozoan phyla Brachiopoda and Mollusca. However, Bryozoan skeletons are more intricate than those of these two phyla. Calcareous skeletons have been acquired independently in two Bryozoan clades - Stenolaemata in the Ordovician and Cheilostomata in the Jurassic - providing an evolutionary replicate. This review aims to highlight the importance of biomineralization in Bryozoans and focuses on their skeletal ultrastructures, mineralogy and chemistry, the roles of organic components, the evolutionary history of bimineralization in Bryozoans with respect to changes in seawater chemistry, and the impact of contemporary global changes, especially ocean acidification, on Bryozoan skeletons. Bryozoan skeletons are constructed from three different wall types (exterior, interior and compound) differing in the presence/absence and location of organic cuticular layers. Skeletal ultrastructures can be classified into wall-parallel (i.e. laminated) and wall-perpendicular (i.e. prismatic) fabrics, the latter apparently found in only one of the two biomineralizing clades (Cheilostomata), which is also the only clade to biomineralize aragonite. A plethora of ultrastructural fabrics can be recognized and most occur in combination with other fabrics to constitute a fabric suite. The proportion of aragonitic and bimineralic Bryozoans, as well as the Mg content of Bryozoan skeletons, show a latitudinal increase into the warmer waters of the tropics. Responses of Bryozoan mineralogy and skeletal thickness to oscillations between calcite and aragonite seas through geological time are equivocal. Field and laboratory studies of living Bryozoans have shown that predicted future changes in pH (ocean acidification) combined with global warming are likely to have detrimental effects on calcification, growth rate and production of polymorphic zooids for defence and reproduction, although some species exhibit reasonable levels of resilience. Some key questions about Bryozoan biomineralization that need to be addressed are identified.
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secular changes in colony forms and Bryozoan carbonate sediments through geological history
Sedimentology, 2013Co-Authors: Paul D. Taylor, Noel P JamesAbstract:Ever since their first radiation in the Ordovician, Bryozoans have contributed significantly to carbonate sedimentation. Most of the numerous colony-forms developed by Bryozoans have evolved repeatedly in different taxonomic groups and vary in their sediment-producing potential. There are nine basic Bryozoan colony-forms: encrusting, dome-shaped, palmate, foliose, fenestrate, robust branching, delicate branching, articulated and free-living. The proportion of these morphotypes in Bryozoan faunas period by period is shown to change significantly through the Phanerozoic. Notable patterns include: (i) steady increase in the number and proportion of encrusting species through time, interrupted by a transient drop in the Late Palaeozoic; (ii) post-Triassic decrease in robust branching colonies; (iii) rise in the proportion of fenestrate colonies through the Palaeozoic, followed by their absence in the Triassic and Jurassic, rarity in the Cretaceous and reappearance in smaller proportions in the Cenozoic; and (iv) scarcity of articulated colonies and absence of free-living colonies until the Cretaceous. Most Palaeozoic Bryozoan sediments come from two architecturally distinct groups of colonies: (i) domal, delicate branching, robust branching and palmate; and (ii) fenestrate. The former generate coarse particles both as sediment and components of stromatoporoid-coral reefs in the Early and mid Palaeozoic, whereas the delicate lacy fans of the latter create both prolific coarse sediment and form the cores of Late Palaeozoic deep-water, sub-photic biogenic mounds. Nearly all post-Palaeozoic Bryozoan sediments comprise cyclostomes and cheilostomes with many of the same growth forms but with the addition of free-living colonies and significant numbers of articulated colonies. The latter produced sand and mud-sized Bryozoan sediment via disarticulation for the first time. In contrast to the Palaeozoic, post-Palaeozoic Bryozoans generated sediment varying more widely across the grain-size spectrum, from mud to sand to gravel. This article highlights the need to consider evolutionary changes in carbonate-producing organisms when interpreting facies changes through time.
Zoya Tolokonnikova - One of the best experts on this subject based on the ideXlab platform.
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Richness of Famennian-Tournaisian (late Devonian-early Carboniferous) Bryozoans in shallow areas of Palaeotethys and Palaeoasian oceans
Palaeobiodiversity and Palaeoenvironments, 2021Co-Authors: Zoya Tolokonnikova, Andrej ErnstAbstract:Based on the analysis of data on Bryozoan localities in territory of modern Eurasia, changes of the Bryozoan richness were calculated in detail for six time slices in the interval from the early Famennian to the late Tournaisian. Highest extinction tempo was observed for the latest Famennian, apparently linked to the Hangenberg Event. However, in the richness of Bryozoans during the late-latest Famennian, an abrupt increase in the origination tempo is observed, as well as a slight decrease in the total Bryozoan richness at the Devonian-Carboniferous transition. Origination of abundant narrowly specialised Bryozoan genera in the orders Trepostomata and Cryptostomata at the end of the Devonian and in the beginning of the Carboniferous was caused by the combined influence of extrinsic and intrinsic factors. An observed increase in the morphological specialisation of Bryozoans during the Late Devonian and early Carboniferous coincides with patterns observed in other benthic organisms such as brachiopods and rugose corals. These patterns can be explained by vacation of ecological niches and changes in the structure of the marine biota in the aftermath of the Hangenberg Event.
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a Bryozoan fauna from the mississippian tournaisian and visean of belgium
Geobios, 2017Co-Authors: Andrej Ernst, Zoya Tolokonnikova, Edouard Poty, Bernard MottequinAbstract:Eleven Bryozoan species are described from the Mississippian of southern Belgium, including one new species, Atactotoechus vaulxensis, and one species left in open nomenclature (Stenophragmidium sp.). From this fauna, four species are restricted to the Tournaisian stage, and seven occur in the Visean. The fauna is mainly small-sized, represented by branched ramose, encrusting and reticulate growth forms. Bryozoans in the Mississippian of southern Belgium preferred deeper, clay-rich environments. The identified Bryozoan species are mainly distributed within the European basin, with some similarities with the Mississippian faunas of Siberia and Kazakhstan.
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Palaeobiogeography of Famennian (Late Devonian) Bryozoans
Palaeogeography Palaeoclimatology Palaeoecology, 2010Co-Authors: Zoya Tolokonnikova, Andrej ErnstAbstract:Abstract Bryozoans were widely distributed in marine habitats of the Famennian (Late Devonian) worldwide. This time interval was marked by gradual change in taxonomic composition of Bryozoan faunas, which were insignificantly affected by global events (Upper Kellwasser, Handerberg). Distribution of Bryozoan faunas was controlled by intrinsic factors (macroevolution) as well as extrinsic factors (eustasy, plate tectonic and volcanic activity). Palaeobiogeographic analysis of Bryozoan associations reveals closest similarities between Tian Shan and Kazakhstan during the early to middle Famennian and between the Altay-Sayan Fold Belt, Transbaikalia and Mongolia during the late Famennian. Migration patterns of Bryozoan faunas during the Famennian are reconstructed, showing main dispersions from the marine basins of Northern China to Kazakhstan and western offshoots of Tian Shan, and then to other areas. Biostratigraphic markers based on Bryozoan taxa are established for each substage (lower, middle and upper Famennian) within relevant regions.
Joachim Scholz - One of the best experts on this subject based on the ideXlab platform.
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Bryozoans and microbial communities of cool-temperate to subtropical latitudes—paleoecological implications
Facies, 2005Co-Authors: Jürgen Kaselowsky, Joachim Scholz, Shunsuke F. Mawatari, P. Keith Probert, Gisela Gerdes, Nicole Kadagies, Gero HillmerAbstract:The environmental distribution of encrusting Bryozoans settling on disarticulated and living bivalve shells has been recorded from five stations in Japan and New Zealand. Some insight into the observed distribution patterns emerges from information on the interaction of Bryozoans with microbial mats. Advancing existing classifications, we have subdivided the encrusting Bryozoan morphotypes into seven different growth types that largely reflect the biological potentials of Bryozoans in competition for space on substrate surfaces. The frequency distribution of these types (s-/c-/m-/z-laminae, runners, spots, bryostromatolites) reveals the influence of microbial mats as a control factor of Bryozoan substrate coverage. Microbial mats in turn are correlated with latitudinal gradients in Japan and New Zealand from cool-temperate to subtropical and tropical waters. Unlike erect Bryozoans, laminar ones are probably underrated as facies fossils. Accordingly, laminar Bryozoan growth types are reconsidered as a tool for paleoecological interpretation of marine hard substrate communities.
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Bryozoans and microbial communities of cool-temperate to subtropical latitudes—paleoecological implications
Facies, 2005Co-Authors: Gisela Gerdes, Jürgen Kaselowsky, Nicole Kadagies, Antje Lauer, Joachim ScholzAbstract:Laminar Bryozoans of shallow marine sites from cool-temperate to subtropical climate in Japan and New Zealand tolerated mainly agglutinated biofilms composed of diatoms, fungi, cyanobacteria and other bacteria as well as debris trapped in slimes. Also monobacterial films were relatively frequent on living Bryozoans, while rigid, tangled mats of filamentous cyanobacteria mainly occupied surrounding substrates or dead Bryozoan colonies. Three levels of microbial fouling low, medium and high were defined. Low-level fouling was more frequent on Bryozoan colonies collected at warm-water settings, while medium levels became more frequent in cooler water. The decrease of microbial fouling towards lower latitudes parallels findings in part one of this study (Kaselowsky et al. 2004 , this volume) in which Bryozoan lamina types comparatively strong in overgrowth competition increased towards lower latitudes. Such morphological signals of competitive interaction of Bryozoans and associated epizoic biofilms are potentially of paleoecologic value. Our collections from two different sampling periods revealed only small changes between seasons which may account for the predominance of oceanographic factors controlling shallow marine sampling sites around Japan and New Zealand coasts.
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The biological potential of encrusting Bryozoans
Senckenbergiana lethaea, 2002Co-Authors: Jürgen Kaselowsky, Joachim Scholz, George S. LevitAbstract:Bryozoans are clonal and modular animals that have a considerable biological potential to perform tactical (reactive) colony growth alterations. The species-specific biological potential of Bryozoans to react to external stimuli enables us to subdivide the encrusting Bryozoan morphotypes into several different pathways of ‘morphoprocesses’. The frequency distribution of these types (z-/m-/c-/s-laminae, runner, spots, bryostromatolites) illustrates the importance of microbial mats as a controlling factor of Bryozoan substrate coverage.
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Microbial mats associated with Bryozoans (Coorong Lagoon, South Australia)
Facies, 1999Co-Authors: Katarzyna A. Palinska, Joachim Scholz, Gisela Gerdes, Katja Sterflinger, Yvonne BoneAbstract:Bryostromatolites are laminated carbonate rocks composed of Bryozoan zoarial laminae. The laminated texture is frequently caused by patterns of Bryozoan self overgrowth as a regular defensive tactic against microbial fouling. In the Coorong Lagoon (South Australia), another type of bryostromatolite is present where the laminated growth of the weakly calcifying Bryozoan species Conopeum aciculata is postmortally stabilized by cyanobacterial mats at the surface, and fungal mats settling in the zooecial cavities. A tough extracellular slime network produced by benthic cyanobacteria is a trap for sediment particles, provides a method of adhesion to the Bryozoan substrate, and produces a biological lamination by the vertical stratification of dead Bryozoan skeletons. These slimes are also important for the preservation of cell structures and for their fossilization. Seasonal fluctuations in salinity and water level are the most important regional control factors, causing a phase displacement in the growth optima of microbial mats and Bryozoans, thereby resulting in a rigid bryostromatolitic fabric.
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Reef-Bryozoans and Bryozoan-microreefs: Control factor evidence from the philippines and other regions
Facies, 1995Co-Authors: Joachim Scholz, Gero HillmerAbstract:In this paper, a preliminary concept on the interplay of local, regional and global control factors of Bryozoan diversity and distribution pattern is introduced. Recent Bryozoans from the Philippines, New Zealand and the Gulf of Aqaba are compared to the selected fossil specimens from the Oxfordian and Santonian.
Igor A. Kosevich - One of the best experts on this subject based on the ideXlab platform.
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The nervous system in the cyclostome Bryozoan Crisia eburnea as revealed by transmission electron and confocal laser scanning microscopy
BMC, 2018Co-Authors: Elena N. Temereva, Igor A. KosevichAbstract:Abstract Introduction Among Bryozoans, cyclostome anatomy is the least studied by modern methods. New data on the nervous system fill the gap in our knowledge and make morphological analysis much more fruitful to resolve some questions of Bryozoan evolution and phylogeny. Results The nervous system of cyclostome Crisia eburnea was studied by transmission electron microscopy and confocal laser scanning microscopy. The cerebral ganglion has an upper concavity and a small inner cavity filled with cilia and microvilli, thus exhibiting features of neuroepithelium. The cerebral ganglion is associated with the circumoral nerve ring, the circumpharyngeal nerve ring, and the outer nerve ring. Each tentacle has six longitudinal neurite bundles. The body wall is innervated by thick paired longitudinal nerves. Circular nerves are associated with atrial sphincter. A membranous sac, cardia, and caecum all have nervous plexus. Conclusion The nervous system of the cyclostome C. eburnea combines phylactolaemate and gymnolaemate features. Innervation of tentacles by six neurite bundles is similar of that in Phylactolaemata. The presence of circumpharyngeal nerve ring and outer nerve ring is characteristic of both, Cyclostomata and Gymnolaemata. The structure of the cerebral ganglion may be regarded as a result of transformation of hypothetical ancestral neuroepithelium. Primitive cerebral ganglion and combination of nerve plexus and cords in the nervous system of C. eburnea allows to suggest that the nerve system topography of C. eburnea may represent an ancestral state of nervous system organization in Bryozoa. Several scenarios describing evolution of the cerebral ganglion in different Bryozoan groups are proposed
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the nervous system in the cyclostome Bryozoan crisia eburnea as revealed by transmission electron and confocal laser scanning microscopy
Frontiers in Zoology, 2018Co-Authors: Elena N. Temereva, Igor A. KosevichAbstract:Among Bryozoans, cyclostome anatomy is the least studied by modern methods. New data on the nervous system fill the gap in our knowledge and make morphological analysis much more fruitful to resolve some questions of Bryozoan evolution and phylogeny. The nervous system of cyclostome Crisia eburnea was studied by transmission electron microscopy and confocal laser scanning microscopy. The cerebral ganglion has an upper concavity and a small inner cavity filled with cilia and microvilli, thus exhibiting features of neuroepithelium. The cerebral ganglion is associated with the circumoral nerve ring, the circumpharyngeal nerve ring, and the outer nerve ring. Each tentacle has six longitudinal neurite bundles. The body wall is innervated by thick paired longitudinal nerves. Circular nerves are associated with atrial sphincter. A membranous sac, cardia, and caecum all have nervous plexus. The nervous system of the cyclostome C. eburnea combines phylactolaemate and gymnolaemate features. Innervation of tentacles by six neurite bundles is similar of that in Phylactolaemata. The presence of circumpharyngeal nerve ring and outer nerve ring is characteristic of both, Cyclostomata and Gymnolaemata. The structure of the cerebral ganglion may be regarded as a result of transformation of hypothetical ancestral neuroepithelium. Primitive cerebral ganglion and combination of nerve plexus and cords in the nervous system of C. eburnea allows to suggest that the nerve system topography of C. eburnea may represent an ancestral state of nervous system organization in Bryozoa. Several scenarios describing evolution of the cerebral ganglion in different Bryozoan groups are proposed.
