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Wyszukujesz frazę "craspeditidae" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
A new type of shell malformation caused by epizoans in Late Jurassic ammonites from Central Russia
Autorzy:
MIRONENKO, ALEKSANDR A.
Powiązania:
https://bibliotekanauki.pl/articles/945743.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
ammonoidea
craspeditidae
kachpurites
parasites
epifauna
jurassic
russia
Opis:
A new type of shell damage on Late Jurassic ammonite Kachpurites fulgens is described. The new type of shell malformation consists of small elongated pits, arranged in groups on the surface of ammonite shell and concentrated near the terminal aperture. The examination of the pits demonstrated no signs of drilling, biting, or healing of punctures. The shell layers in the pits are bent downward without changing in thickness. At the same time the pits, in some cases, significantly distort the shape of the shell walls. Deformed growth lines are associated with some of the pits. All of this supports the hypothesis that the pits had been formed by epifauna located at a flexible uncalcified part of the periostracum in the apertural region of the growing ammonite shell. It is likely that epizoan attachment led to the deformation of the thin periostracum film and to the distortion of the growing shell wall. The nature of epizoans is discussed, but remains unclear due to their rather poor preservation. The relationship between epizoans and ammonites is also an open question: they could have been parasites, but other types of biotic relationships cannot be entirely ruled out.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 3; 645-660
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The soft-tissue attachment scars in Late Jurassic ammonites from Central Russia
Autorzy:
Mironenko, A.A.
Powiązania:
https://bibliotekanauki.pl/articles/22288.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ammonoidea
Craspeditidae
Kachpurites
Garniericeras
soft tissue attachment
attachment scar
Late Jurassic
Jurassic
ammonite
paleobiology
Central Russia
Russia
Opis:
Soft-tissue attachment scars of two genera and four species of Late Jurassic craspeditid ammonites from the Russian Platform are described. A previously suggested relationship between lateral attachment scars and ammonoid hyponome is confirmed, however, a new interpretation is proposed for dorsal attachment scars: they could have been areas not only for attachment of the dorsal (nuchal) retractors, but also of the cephalic retractors. The new type of the soft-tissue attachment—anterior lateral sinuses, located between the lateral attachment scars and the aperture of the ammonite body chamber is described. Enclosed elliptical or subtriangular areas in apertural parts of the anterior lateral sinuses were found for the first time. Their presence and location suggest that this structure could have been used for attaching the funnel-locking apparatus, similar to those of coleoids. A transformation of shape and position of lateral attachment scars through the evolution of the Late Jurassic craspeditid lineage starting from platycones (Kachpurites fulgens) to keeled oxycones (Garniericeras catenulatum) is recognized.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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