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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 conulariids with trepostome Bryozoans in the upper ordovician of estonia baltica
Palaeogeography Palaeoclimatology Palaeoecology, 2019Co-Authors: Olev Vinn, Andrej Ernst, Mark A. Wilson, Ursula ToomAbstract:Abstract The trepostome Bryozoans Diplotrypa abnormis, D. bicornis, D. petropolitana, Esthoniopora communis, E. subsphaerica, Mesotrypa excentrica, M. expressa, M. raritabulata, and Monotrypa jewensis have symbiotic associations with the conulariid Climacoconus bottnicus in the Upper Ordovician of Estonia. All bryoimmured conulariids are very small and oriented perpendicular (or nearly so) to the growth surface of the host trepostome colony. Muddy seafloors may have promoted this symbiosis between conulariids and Bryozoans because the former required a hard substrate for attachment. It is possible that the numerous smaller specimens among endobiotic conulariids usually died as juveniles together with their bryozoan host, or alternatively, the smaller endobiotic conulariids may have been Lilliput forms of free-living conulariids that died at a mature age. Conulariid-trepostome associations were likely not a result of accidental intergrowth of two organisms. Additional protection against predators provided by the calcitic bryozoan skeleton may have been among the benefits for the conulariid symbionts. Usually trepostomes with conulariid symbionts do not contain other invertebrates, but in the Katian in some cases they also hosted Anoigmaichnus bioclaustrations. The exact type of symbiosis between trepostomes and conulariids remains unresolved, but most likely the associations were slightly parasitic or commensal. The available data suggest that Bryozoans preferred cnidarians over the other invertebrates as symbionts.
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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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Palaeoecology of Famennian-Tournaisian (Late Devonian-Early Carboniferous) Bryozoans from central and southern regions of Russia
Palaeobiodiversity and Palaeoenvironments, 2017Co-Authors: Zoya Tolokonnikova, Andrej ErnstAbstract:The palaeoecology of Famennian-Tournaisian (Late Devonian-Early Carboniferous) Bryozoans from central and southern regions of Russia is analysed. Famennian-Tournaisian Bryozoans associations of the Altai-Sayan Folded Area and the south-western region of the West-Siberian plate was a shallow-middle shelf according to our own and literature data. Robust branching-fenestrate-bilaminar bryozoan associations are found in locations of warm water, transitional low-high water energy, normal salinity and changing sedimentation rate. Bryozoan associations from South Urals and the central part of the Russian plate are characterised by a low number of species and specimens. Encrusting unilaminar and delicate branching growth habits are dominate in the Russian Plate and indicate an environmental setting in close proximity to strandline.
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Diversity dynamics of Ordovician bryozoa
Lethaia, 2017Co-Authors: Andrej ErnstAbstract:This study presents a compilation of the temporal distribution of 200 bryozoan genera during the Ordovician. Bryozoans appeared in the earliest Ordovician (Tremadoc), diversified rapidly until the late Sandbian, and then suffered three distinct extinctions in the Late Ordovician. In the early Katian, the first significant extinction eliminated 22.7% of bryozoan genera. That was the highest taxonomic loss in the Ordovician; however, due to high origination rates, the magnitude of this extinction was the lowest among the three extinctions. The second extinction wave occurred in the late Katian, resulting in taxonomic loss of 22.4%. This event can be estimated as the most severe for Bryozoans during the Ordovician because of extremely low origination rates what resulted in the highest net decrease of diversity. The third extinction of Bryozoans occurred during the Hirnantian resulting in the lowest taxonomic loss (16.5%) and intermediate net decrease of diversity. The diversity dynamics of Bryozoans in the Ordovician was apparently controlled by climatic changes, provinciality and food availability.
Lars Stemmerik - One of the best experts on this subject based on the ideXlab platform.
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Upper Permian Bryozoans of central East Greenland
Bulletin of the Geological Society of Denmark, 2008Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:The bryozoan fauna in the Upper Permian Wegener Halvø, Ravnefjeld and Schuchert Dal formations, central East Greenland is of modest diversity, with only 15 genera identified. Bryozoans are most abundant in the Wegener Halvø Formation where they are important in the formation of carbonate buildups. Robust, rigidly erect colony types dominate in buildup cores whereas delicate erect types characterize the distal parts of the buildups. Cement-dominated bryozoan buildups are found in East Greenland and in the Zechstein Basin but are not known from the contemporaneous cool-water successions of North Greenland and Svalbard. The buildups are probably formed by seawater chemistry facilitating syn-depositional cement rather than a difference in the composition of the bryozoan fauna.
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faunal migration into the late permian zechstein basin evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:Abstract Late Permian Bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian Bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for Bryozoans to enter the basin. The distribution of Permian Bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
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Faunal migration into the Late Permian Zechstein Basin – Evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:Abstract Late Permian Bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian Bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for Bryozoans to enter the basin. The distribution of Permian Bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
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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Permian Bryozoans from the Nemda horizon (Roadian) of Samara Region, Russia
PalZ, 2020Co-Authors: Zoya TolokonnikovaAbstract:Six bryozoan species are described from the Lower Roadian (Guadalupian) of the eastern part of the East European Platform. The studied fauna is abundant and represented by various growth habits (branching, massive, encrusting, reticulate), developed in local bioherms. The studied bryozoan assemblage consists of trepostomes (three species), fenestrates (two species) and one cryptostome species with specific exozonal skeletons. Trepostomes of genus Dyscritella are dominant in this bryozoan association and possess acanthostyles differentiated by size. These structures probably performed protective and fixing functions. Fenestrate Bryozoans have funnel-shaped and reticulate colonies with superstructure, which could have developed to protect against rapid sedimentation and predators. The identified bryozoan species are widely distributed within the East European Platform, with some similarities to the Roadian fauna of Transcaucasia, Guadalupian fauna of the Primorskij Kraj and Omolon massif.
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Palaeoecology of Famennian-Tournaisian (Late Devonian-Early Carboniferous) Bryozoans from central and southern regions of Russia
Palaeobiodiversity and Palaeoenvironments, 2017Co-Authors: Zoya Tolokonnikova, Andrej ErnstAbstract:The palaeoecology of Famennian-Tournaisian (Late Devonian-Early Carboniferous) Bryozoans from central and southern regions of Russia is analysed. Famennian-Tournaisian Bryozoans associations of the Altai-Sayan Folded Area and the south-western region of the West-Siberian plate was a shallow-middle shelf according to our own and literature data. Robust branching-fenestrate-bilaminar bryozoan associations are found in locations of warm water, transitional low-high water energy, normal salinity and changing sedimentation rate. Bryozoan associations from South Urals and the central part of the Russian plate are characterised by a low number of species and specimens. Encrusting unilaminar and delicate branching growth habits are dominate in the Russian Plate and indicate an environmental setting in close proximity to strandline.
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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.
Paul D. Taylor - One of the best experts on this subject based on the ideXlab platform.
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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.
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a new middle devonian cystoporate bryozoan from germany containing a new symbiont bioclaustration
Acta Palaeontologica Polonica, 2012Co-Authors: Andrej Ernst, Paul D. Taylor, Jan BohatýAbstract:An unusual cystoporate bryozoan from the Middle Devonian (Givetian) Ahbach Formation of the Hillersheim Syncline (Eifel, Rhenish Massif, Germany) is described as Stellatoides muellertchensis gen. et sp. nov. The lamellar colonies have elongate stellate maculae with depressed centres consisting of vesicular skeleton. All colonies collected contain vertical axial tubular holes, which are embedment structures formed by the bryozoan around a soft-bodied symbiont and lined by bryozoan skeleton. These bioclaustrations are referred to the ichnogenus Chaetosalpinx, previously known in Ordovician—Devonian corals and sponges, and are described as Chaetosalpinx tapanilai ichnosp. nov. Ecological analogues to Chaetosalpinx tapanilai can be found in modern Bryozoans in which tubes formed of bryozoan calcite are occupied by spionid polychaetes, or less often tanaidacean crustaceans.
Anne Mehlin Sørensen - One of the best experts on this subject based on the ideXlab platform.
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Upper Permian Bryozoans of central East Greenland
Bulletin of the Geological Society of Denmark, 2008Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:The bryozoan fauna in the Upper Permian Wegener Halvø, Ravnefjeld and Schuchert Dal formations, central East Greenland is of modest diversity, with only 15 genera identified. Bryozoans are most abundant in the Wegener Halvø Formation where they are important in the formation of carbonate buildups. Robust, rigidly erect colony types dominate in buildup cores whereas delicate erect types characterize the distal parts of the buildups. Cement-dominated bryozoan buildups are found in East Greenland and in the Zechstein Basin but are not known from the contemporaneous cool-water successions of North Greenland and Svalbard. The buildups are probably formed by seawater chemistry facilitating syn-depositional cement rather than a difference in the composition of the bryozoan fauna.
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faunal migration into the late permian zechstein basin evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:Abstract Late Permian Bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian Bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for Bryozoans to enter the basin. The distribution of Permian Bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
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Faunal migration into the Late Permian Zechstein Basin – Evidence from bryozoan palaeobiogeography
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Anne Mehlin Sørensen, Eckart Håkansson, Lars StemmerikAbstract:Abstract Late Permian Bryozoans from the Wegener Halvo, Ravnefjeld and Schuchert Formations in East Greenland have been investigated. 14 genera are recognised. Integration of the new bryozoan data from the Upper Permian of East Greenland with data on the distribution of Permian Bryozoans along the northern margin of Pangea is used to test hypotheses concerning Late Palaeozoic evolution of the North Atlantic region. During the Permian, the Atlantic rift system formed a seaway between Norway and Greenland from the boreal Barents Shelf to the warm and arid Zechstein Basin. This seaway is considered to be the only marine connection to the Zechstein Basin and therefore the only possible migration route for Bryozoans to enter the basin. The distribution of Permian Bryozoans is largely in keeping with such a connection from the cool Barents Shelf past the East Greenland Basin to the warm Zechstein Basin and also corroborates the change in temperature through this connection.
