Temat: Graptolithoidea - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Discovery of Pterobranchia [Graptolithoidea] in the Permian
Autorzy:: Mierzejewski, P
Kulicki, C.
Powiązania:: https://bibliotekanauki.pl/articles/19944.pdf
Data publikacji:: 2002
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: fossil remains
Graptolithina
Graptolithoidea
paleobiology
Permian
remains
Norway
Rhabdopleuroidea
Pterobranchia
Opis:: The fossil remains of a hemichordate exoskeleton, recognized as fragments of the stolons and their cyst−like swellings connected with the fusellar zooidal tubes, were derived by chemical isolations from Late Permian (Kazanian) mudstones of the Svalis Dome (central Barents Sea, Norway). These fossils, referred to as Diplohydra szaniawskii sp. nov., are the first undoubted representatives of the class Graptolithoidea found in Permian deposits. The genus Diplohydra Kozłowski, 1959, known previously only from the Ordovician and originally established as a thecate hydroid taxon, is reinterpreted as an aberrant member of the order Rhabdopleuroidea. This strange hemichordate, characterized by fusellar tubes distinctly narrower than stolon−like tubes and their swellings, reveals a certain degree of dimorphism in the stolon system. D. szaniawskii sp. nov. also displays some peculiar morphological features common to the Ordovician rhabdopleuroid genus Rhabdopleurites Kozłowski and the stolonoid genus Stolonodendrum Kozłowski.
Źródło:: Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Cortical fibrils and secondary deposits in periderm of the hemichordate Rhabdopleura [Graptolithoidea]
Autorzy:: Mierzejewski, P
Kulicki, C.
Powiązania:: https://bibliotekanauki.pl/articles/22318.pdf
Data publikacji:: 2003
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: Hemichordata
fibril
hemichordate
Graptolithoidea
Rhabdopleura
periderm
deposit
Pterobranchia
ultrastructure
paleontology
Opis:: Coenecia of extant hemichordates Rhabdopleura compacta and Rh. normani were investigated using SEM techniques. Cortical fibrils were detected in their fusellar tissue for the first time. The densely packed cortical fibrils form a characteristic band−like construction in fusellar collars, similar to some Ordovician rhabdopleurids. No traces of external secondary deposits are found in coenecia. Two types of internal secondary deposits in tubes are recognized: (1) membranous deposits, composed of numerous, tightly packed sheets, similar to the crustoid paracortex and pseudocortex; and (2) fibrillar deposits, devoid(?) of sheets and made of cortical fibrils, arranged in parallel and interpreted as equivalent to graptolite endocortex. There is no significant difference in either the shape or the dimensions of cortical fibrils found in Rhabdopleura and graptolites. The cortical fabric of both rhabdopleuran species studied is composed of long, straight and more or less wavy, unbranched fibrils arranged in parallel; their diameters vary from 220 to 570 µm. The study shows that there is no significant difference between extinct and extant Graptolithoidea (= Pterobranchia) in the histological and ultrastructural pattern of their primary and secondary deposits of the periderm. The nonfusellar periderm of the prosicula is pitted by many depressions similar to pits in the cortical tissue of graptolites.
Źródło:: Acta Palaeontologica Polonica; 2003, 48, 1
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The ultrastructure and building of graptolite dissepiments
Autorzy:: Urbanek, A
Mierzejewski, P.
Powiązania:: https://bibliotekanauki.pl/articles/22043.pdf
Data publikacji:: 2009
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: paleontology
ultrastructure
graptolite
building
rhabdosome
dendroid graptolite
Hemichordata
Graptolithoidea
Dendroidea
Dictyonema
dissepiment
skeletal tissue
Ordovician
Opis:: Dissepiments or connecting bars between adjacent stipes in rhabdosomes of dendroid graptolites were studied by means of electron microscopy (SEM and TEM). The material, chemically isolated from rock matrix, originating from the Ordovician of Estonia and glacial boulders of Baltic origin found in Poland, is assigned provisionally to the genus “Dictyonema” sensu lato. Early growth stages of dissepiments are made only of the fusellar component. Older dissepiments are composed of the central core and the outer envelope: the central core is made of rather irregularly arranged growth units made of the fusellar tissue, whereas the outer envelope has a distinct cortical appearance. TEM observations indicate that the fusellar component is made of both typical fusellar and microfusellar tissues (the latter with complete and reduced microfuselli). The cortical component of dissepiments is made both of dependent and independent cortex. The opinion is advanced that the dissepiments were constructed externally by the mortaring activities of zooids, similar to that of Recent Cephalodiscus. Our observations indicate that bizooids were most probable dissepiment constructors. These results, in general, does not support earlier opinions that dissepiments are made of cortical tissue acquiring a fusellar aspect in some cases, and that dissepiments were produced by the extrathecal membrane surrounding the rhabdosome.
Źródło:: Acta Palaeontologica Polonica; 2009, 54, 2; 243-252
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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