Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "shell microstructure" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-2 z 2
    Tytuł:
    New Barremian rhynchonellide brachiopod genus from Serbia and the shell microstructure of Tetrarhynchiidae
    Autorzy:
    Radulovic, B.
    Motchurova-Dekova, N.
    Radulovic, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/20693.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    Barremian
    Brachiopoda
    Cretaceous
    paleobiogeography
    Rhynchonellid
    Serbia
    Tetrarhynchiidae
    paleontology
    phylogenetic implication
    rhynchonellid brachiopod
    shell microstructure
    systematics
    taxonomy
    Opis:
    A new rhynchonellide brachiopod genus Antulanella is erected based on the examination of the external and internal morphologies and shell microstructure of “Rhynchonella pancici”, a common species in the Barremian shallow−water limestones of the Carpatho−Balkanides of eastern Serbia. The new genus is assigned to the subfamily Viarhynchiinae, family Tetrarhynchiidae. The shell of Antulanella is small to rarely medium−sized, subglobose, subcircular, fully costate, with hypothyrid rimmed foramen. The dorsal euseptoidum is much reduced. The dental plates are thin, ventrally divergent. The hinge plates are straight to ventrally convex. The crura possess widened distal ends, rarely raduliform or canaliform. The shell is composed of two calcitic layers. The secondary layer is fine fibrous, homogeneous built up of predominantly anisometric anvil−like fibres. Although data on the shell microstructure of post−Palaeozoic rhynchonellides are still incomplete, it is possible to distinguish two types of secondary layer: (i) fine fibrous typical of the superfamilies Rhynchonelloidea and Hemithiridoidea and (ii) coarse fibrous typical of the superfamilies Pugnacoidea, Wellerelloidea, and Norelloidea. The new genus Antulanella has a fine fibrous microstructure of the secondary layer, which is consistent with its allocation in the Hemithiridoidea. Antulanella pancici occurs in association with other brachiopods showing strong Peritethyan affinity and close resemblance to the Jura fauna (= Subtethyan fauna).
    Źródło:
    Acta Palaeontologica Polonica; 2007, 52, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Shell microstructures in Early Cambrian molluscs
    Autorzy:
    Kouchinsky, A
    Powiązania:
    https://bibliotekanauki.pl/articles/23294.pdf
    Data publikacji:
    2000
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    skeletal fossil
    microstructure
    shell
    biomineralization
    mollusc
    Early Cambrian
    mollusc-like organism
    taxonomy
    Cambrian
    paleontology
    Opis:
    The affinities of a considerable part of the earliest skeletal fossils are problematical, but investigation of their microstructures may be useful for understanding biomineralization mechanisms in early metazoans and helpful for their taxonomy. The skeletons of Early Cambrian mollusc-like organisms increased by marginal secretion of new growth lamellae or sclerites, the recognized basal elements of which were fibers of apparently aragonite. The juvenile part of some composite shells consisted of needle-like sclerites; the adult part was built of hollow leaf-like sclerites. A layer of mineralized prism-like units (low aragonitic prisms or flattened spherulites) surrounded by an organic matrix possibly existed in most of the shells with continuous walls. The distribution of initial points of the prism-like units on a periostracurn-like sheet and their growth rate were mostly regular. The units may be replicated on the surface of internal molds as shallow concave polygons, which may contain a more or less well-expressed tubercle in their center. Tubercles are often not enclosed in concave polygons and may co-occur with other types of textures. Convex polygons seem to have resulted from decalcification of prism-like units. They do not co-occur with tubercles. The latter are interpreted as casts of pore channels in the wall possibly playing a role in biomineralization or pits serving as attachment sites of groups of mantle cells. Casts of fibers and/or lamellar units may overlap a polygonal texture or occur without it. They may reflect an inner layer consisting of aragonitic fibers fused into more or less well-developed lamellar units. It seems that nacreous and crossed-lamellar aragonitic microstructures evolved in the Cambrian from such lamellar aragonitic microstructures independently in different groups of molluscs.
    Źródło:
    Acta Palaeontologica Polonica; 2000, 45, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-2 z 2

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies