Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 19

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Bryozoa
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Bryozoans from the Nordenskiöldbreen Formation (Middle Carboniferous Moscovian through Early Permian Sakmarian) and the Gipshuken Formation (late Sakmarian - late Artinskian), from central Spitsbergen, Svalbard, are represented by 36 species (22 genera). One species is new: Hinaclema svalbardensis of the order Trepostomata. The bryozoan fauna is typical Boreal and resembles those from the Timan-Pechora region (western Siberia) and the Urals. Similarity indices based on generic composition show that the Boreal fauna became more endemic by the late Early Permian, clearly separated from the Tethyan faunas. Several species have stratigraphic ranges in Spitsbergen longer than elsewhere.
Bryozoans from the Lower Permian Treskelodden and Wordiekammen formations of southern and central Spitsbergen respectively, Svalbard, have been studied. Twenty species are identified, including one new genus, Toulapora gen. nov., with Toulapora svalbardense as type species and one new species, Ascopora birkenmajeri sp. nov. The taxonomic composition is typical Lower Permian, with species in common with Timan−Pechora and the Urals (Russia) and Ellesmere Island (the Canadian Arctic). Growth habits reflect a moderately to deeper shelf environment.
Bryozoans are widely distributed benthic invertebrates which form colonies both in running and stagnant waters. There are 19 freshwater species of Bryozoa in Europe, and only three have been recorded in Serbia so far. Statoblasts (the dormant stages of these colonial animals) are relatively frequently found in the gut contents of fish, but those of the Hyalinella punctata species (Phylactolaemata) have not been registered. Statoblasts of H. punctata were determined for the first time in the gut content of chub Leuciscus cephalus sampled from the Zapadna Morava River (West Serbia, Danube River basin) in late summer and autumn. The intactness in form supports their viability after the passage through intestines, implying that the fish may be a vector of the dispersal of H. punctata in new aquatic habitats, as well as a risk factor in the transmission of certain salmonid fish disease agents into fish farms and natural habitats.
Sixteen bryozoan species have been identified in the Başyayla section, Mut Basin, southern Turkey. Five of these species are described here, including two new to science representing new genera: Basyaylella elsae gen. et sp. nov. and Ostrovskia triforamina gen. et sp. nov. The other three described species (Exidmonea sp., Biflustra savartii, and Margaretta sp.) show unusual features that have not been reported previously. Based on bryozoan data, the Başyayla sequence represents a tropical to subtropical, normal marine environment, with seafloor composed of fine sedimentary particles in a low−energy setting.
Colonies of boring ctenostome bryozoans and microborings of “fungi” that occur in the Early Devonian (Lochkovian, ~416 Ma) of Podolia, western Ukraine, have soft−tissue preserved by phosphatization. These comprise exceptional three−dimensional body walls of feeding zooids with probable parietal muscles inserted on the cystid wall, and setigerous collars twisted within the vestibulum. The presence of collars in this Early Devonian ctenostomes proves the existence of this feature for more than 416 Ma of ctenostome evolution. Phosphatized remains of the zooid walls are interpreted as relicts of the originally chitinous cystid walls. This is the first record of soft−tissue fossilization in a boring bryozoan. The presence of cavities (specialized heterozooids), empty or filled with laminated calcium phosphate, is also documented in bryozoans for the first time. These cavities are interpreted as “store−rooms” in which the bryozoans accumulated nutrients. The new taxon, Podoliapora doroshevi gen. et sp. nov. is described. In additional, phosphatised fungi−like endoliths co−occur with bryozoans.
13
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Late Carboniferous bryozoans from La Hermida, Spain

67%
Fifteen bryozoan species belonging to thirteen genera have been identified from an outcrop of the Picos de Europa Formation (Moscovian, Upper Carboniferous) at La Hermida in northern Spain. Three species and one genus are new— Coscinium hermidensissp. nov., Cystodictya pustulosa sp. nov., and Cystocladia hispanica gen. et sp. nov. Rhabdomesid bryozoans are the most diverse order with seven species, followed by cystoporids (four species), fenestellids (three species) and trepostomids (one species). Bryozoans with erect branched or reticulate colonies dominate in the studied assemblage; only two species possess encrusting colonies. Together with associated crinoids, the bryozoan assemblage indicates a subtidal environment below the zone of vigorous water movement. The La Hermida bryozoan fauna confirms the Upper Carboniferous age of the Picos de Europa Formation and allows various biogeographical interpretations. All previously known species of the genus Coscinium were reported from the Lower Permian of Russia. Clausotrypa monticola is known from the Lower Permian of Russia and Arctic as well as from the Upper Carboniferous of Carnic Alps (Austria). Rhabdomeson cf. propatulissimum and Penniretepora pseudotrilineata are known from the same level of Italian Carnic Alps. Streblotrypa (Streblascopora) nikiforovae and Rhombocladia punctata are known from the Upper Carboniferous (Moscovian) of Ukraine. Fistulipora petaloida is known from Kasimovian Stage of Russian Plate. Several other species show connections with North America.
Devonian bryozoans have been investigated from two Givetian to Frasnian localities in the Holy Cross Mts (Central Poland), representing fossiliferous ramp slope facies of the Kostomłoty facies zone (north−western periphery of the Kielce carbonate platform). Thirteen genera belonging to four families and three orders have been identified. Bryozoans show close relation to previously described Givetian and Frasnian bryozoan faunas of France, but also some affinities to easterly regions (e.g., Kuzbass). The main immigration episodes are related to late Givetian and middle Frasnian deepening pulses. The replacement of locally rich and diverse Givetian carbonate bank faunas by overall impoverished Frasnian reef−complex associations largely corresponds to a major extinction event in the evolutionary history of Bryozoa. Five new species are described by I. Morozova and O. Weis: Eridotrypella arguta, Eridotrypella exserta, Eostenopora nimia, Primorella nitida, Primorella indigena.
Dome−shaped cheilostome bryozoan colonies, most commonly about 2 cm in diameter, are common in Upper Eocene offshore deposits of southeastern North Carolina, USA.This colony−form is anachronistic in the Eocene, being more typical of Palaeozoic bryozoans.There are three types of domes: individual colonies of Parasmittina collum (Canu and Bassler), individual colonies of Osthimosia glomerata (Gabb and Horn) and multispecies intergrowths.The bryozoans grew laterally beyond initial shell substrata to become free−lying. P. collum colonies grew by local eruptive budding, forming subcolonies that extended radially over the underlying layer of zooids.Undersides of subcolonies that extended beyond the original substratum have basal exterior walls that are more commonly fouled by encrusters than is the upper side of the colony.By contrast, lateral growth of O. glomerata colonies was limited by size of the original substratum, subcolonies were not developed, and colony growth occurred by prolific frontal budding over the entire upper surface of the colony. Undersides of colonies beyond the substratum consist of the lateral interior walls of marginal zooids and are much less commonly fouled than are undersurfaces of P. collum.The upper surfaces of multispecies domes by definition are always fouled, and their undersurfaces are also commonly fouled.
18
59%
New collections of bryozoans from the Middle Jurassic (Late Bajocian and Bathonian) of Poland add significantly to our knowledge of the diversity and biogeography of the Cyclostomata at a time when they were the dominant bryozoan order in the fossil record. A total of 16 species and one form−genus (“Berenicea”) are present. Most are encrusters, predominantly on hiatus concretions. A single erect species was found in deposits interpreted as regurgitates of a marine vertebrate. The following new species are described: Microeciella annae sp. nov., M. kuklinskii sp. nov., M. maleckii sp. nov., M. mokrskoensis sp. nov., M. magnopora sp. nov., Reptomultisparsa harae sp. nov., and Hyporosopora bugajensis sp. nov. The taxonomic importance of the morphology of both the gonozooids and pseudopores is underlined, especially for encrusting species of the “Berenicea” type that are otherwise difficult to distinguish from one another. The described bryozoan assemblage encrusting hiatus concretions from the Polish Middle Jurassic is the richest that has been documented globally from this kind of substrate.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.