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Wyszukujesz frazę "fossil shell" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Earliest laurasian sauropod eggshells
Autorzy:
Garcia, G
Marivaux, L.
Pelissie, T.
Vianey-Liaud, M.
Powiązania:
https://bibliotekanauki.pl/articles/22561.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
megaloolithid egg shell
Middle Jurassic
Bajocian
Quercy area
France
Sauropoda
fossil egg
paleontology
Opis:
Megaloolithid eggshells, known from many Cretaceous deposits since 19th century, are now recognized as remnants of sauropod dinosaurs. Our paper reports the discovery of megaloolithid egg remains from the Middle Jurassic (Bajocian) of the Quercy area (southwestern France). The new Jurassic ootaxon differs from related Cretaceous oospecies in having unusually thin shells. Even Megaloolithus aureliensis, the thinnest Cretaceous megaloolithid from France is three times thicker than the Jurassic eggshells. The cladistic analysis of ootaxa reveals a peculiar point in contradiction with the phylogenetic results based on skeletal remains: the Megaloolithidae belonged to sauropod dinosaurs, which appear to be the sister group of the hadrosaur eggs (Spheroolithidae oofamilly). This result could indicate a significant amount of homoplasy in the evolution of eggshell structures, depending strongly on the incubation environment (particularly for some characters as ornamentation, pore openings and pore canals), the reproductive physiology and the oviduct function. The Bajocian eggshells might represent the earliest offshoot of the Megaloolithidae oofamily and represent the earliest sauropod eggshell record known from the deposits of Laurasia supercontinent.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioerosion in shell beds from the Pliocene Roussillon Basin, France: Implications for the (macro)bioerosion ichnofacies model
Autorzy:
de Gibert, J.M.
Domenech, R.
Martinell, J.
Powiązania:
https://bibliotekanauki.pl/articles/23006.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
France
geological setting
Gnathichnus pentax
Pliocene
Radulichnus inopinatus
Roussillon Basin
bioerosion
fossil
ichnofacies
ichnofacies model
ichnology
oyster
shell bed
trace fossil
Opis:
The marine Pliocene at the locality of Nefiach (Roussillon Basin, SE France) includes several shell beds constituted by oysters and scallops that bear a diverse and abundant bioerosion trace fossil assemblage. The most abundant trace fossils are Gnathichnus pentax and Radulichnus inopinatus, produced by the grazing activity of echinoids and polyplacophorans upon algae and other microorganisms coating shell surfaces. Other bioerosion traces include polychaete dwellings (Caulostrepsis taeniola and Maeandropolydora sulcans), sponge boring systems (Entobia isp.), and rare bryozoan borings (Pinaceocladichnus isp.), predation structures (Oichnus simplex and repaired durophagous scars), and foraminiferal fixation pits (Centrichnus cf. eccentricus). The trace fossil assemblage records short−term bioerosion in shellgrounds in a moderate energy setting as evinced by the dominance of epigenic or shallow endogenic structures produced in most cases by “instantaneous” behaviors. The assemblage can be assigned to the Gnathichnus ichnofacies, and it contrasts with that found in Pliocene rocky shores in the same geographic area, which are examples of the Entobia ichnofacies. The Gnathichnusichnofacies is validated as an archetypal one and its recurrency demonstrated since the Jurassic. Entobia and Gnathichnus ichnofacies have to be used in the Mesozoic and Cenozoic as substitutes of the previously existing Trypanites ichnofacies, which is still valid in the Palaeozoic.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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