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Wyszukujesz frazę "Roveacrinida" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The microcrinoid taxonomy, biostratigraphy and correlation of the upper Fredericksburg and lower Washita groups (Cretaceous, middle Albian to lower Cenomanian) of northern Texas and southern Oklahoma, USA
Autorzy:
Gale, Andrew Scott
Rashall, Jenny Marie
Kennedy, William James
Holterhoff, Frank Koch
Powiązania:
https://bibliotekanauki.pl/articles/1835606.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Roveacrinida
integrated biostratigraphy
ammonites
planktonic foraminifera
biostratygrafia
amonity
otwornice planktoniczne
Opis:
The stratigraphy of the upper Fredericksburg and lower Washita groups of northern Texas and southern Oklahoma is described, and biostratigraphical correlation within the region, and further afield, using micro-crinoids, ammonites, planktonic foraminiferans and inoceramid bivalves is summarised. The taxonomy of the roveacrind microcrinoids is revised by the senior author, and a new genus, Peckicrinus, is described, with the type species Poecilocrinus porcatus (Peck, 1943). New species include Roveacrinus proteus sp. nov., R. morganae sp. nov., Plotocrinus reidi sp. nov., Pl. molineuxae sp. nov., Pl. rashallae sp. nov. and Styracocrinus thomasae sp. nov. New formae of the genus Poecilocrinus Peck, 1943 are Po. dispandus forma floriformis nov. and Po. dispandus forma discus nov. New formae of the genus Euglyphocrinus Gale, 2019 are E. pyramidalis(Peck, 1943) forma pyramidalis nov., E. pyramidalis forma radix nov. and E. pyramidalis forma pentaspinusnov. The genera Plotocrinus Peck, 1943, Poecilocrinus and Roveacrinus Douglas, 1908 form a branching phylogenetic lineage extending from the middle Albian into the lower Cenomanian, showing rapid speciation, upon which a new roveacrinid zonation for the middle and upper Albian (zones AlR1-12) is largely based. Outside Texas and Oklahoma, zone AlR1 is recorded from the lower middle Albian of Aube (southeastern France) and zones AlR11-CeR2 from the Agadir Basin in Morocco and central Tunisia. It is likely that the zonation will be widely applicable to the middle and upper Albian and lower Cenomanian successions of many other regions.
Źródło:
Acta Geologica Polonica; 2021, 71, 1; 1-52
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functional anatomy and mode of life of the latest Jurassic crinoid Saccocoma
Autorzy:
Brodacki, M
Powiązania:
https://bibliotekanauki.pl/articles/21680.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Saccocoma
Tithonian
brachial articulation
crinoid
Late Jurassic
Roveacrinida
functional anatomy
paleontology
Crinoidea
Opis:
Loose elements of the roveacrinid Saccocoma from the Tithonian red Rogoża Coquina, Rogoźnik, Pieniny Klippen Belt, Poland, are used to test the contradictory opinions on the mode of life of Saccocoma. The investigated elements belong to three morphological groups, which represent at least two separate species: S. tenella, S. vernioryi, and a third form, whose brachials resemble those of S. vernioryi but are equipped with wings of different shape. The geometry of brachials’ articular surfaces reveals that the arms of Saccocoma were relatively inflexible in their proximal part and left the cup at an angle of no more than 45, then spread gradually to the sides. There is no evidence that the wings were permanently oriented in either horizontal or vertical position, as proposed by two different benthic life−style hypotheses. The first secundibrachial was probably more similar to the first primibrachial than to the third secundibrachial, in contrast to the traditional assumption. The winged parts of the arms were too close to the cup and presumably too stiff to propel the animal in the water efficiently. Swimming was probably achieved by movements of the distal, finely branched parts of the arms. The nonhorizontal attitude of the winged parts of the arms is also not entirely consistent with the assumption that they functioned as a parachute. Moreover, the wings added some weight and thus increased the energy costs associated with swimming. The hydrodynamic benefits balancing these extra costs are not entirely clear, but it seems probable that the wings reduced the sinking rate of the animal not by increasing the pressure drag, as suggested by the parachute−analogy, but by increasing the surface drag (friction drag), which also harmonize with the presence of spines, reticulate sculpture and conspicuous vacuolar ornamentation in some species of Saccocoma.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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