Results 11 to 20 of about 202 (155)
3D-Analysis of a non-planispiral ammonoid from the Hunsrück Slate: natural or pathological variation? [PDF]
PeerJ, 2017 We herein examine the only known non-planispirally coiled early Devonian ammonoid, the holotype specimen of Ivoites opitzi, to investigate if the host was encrusted in vivo and if these sclerobionts were responsible for the trochospiral coiling observed ...
Julia Stilkerich +2 more
doaj +3 more sources
VILLANIA'NIN (AMMONOIDEA) TÜRKİYE'DEKİ VARLIĞI HAKKINDA
Bulletin of the Mineral Research and Exploration, 1982 Türkiye'deki varlığı ilk kez saptanan Villania bugüne değin Macaristan'a özgü bilinen bir ammonit cinsidir. Bilecik yöresinde bulunan iki örnek, Villania cf.
Füsun ALKAYA
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Extreme abundance of ammonoids in mass accumulations from the Late Devonian of the Moroccan Anti-Atlas [PDF]
Acta Palaeontologica Polonica, 2022 The eastern Anti-Atlas is renowned for its highly fossiliferous outcrops of Devonian rocks. Ammonoids occur in rock-forming numbers at many localities in the Tafilalt and Maïder.
MERLE GREIF +2 more
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Dimorphism in tetragonitid ammonoid Tetragonites minimus from the Upper Cretaceous in Hokkaido, Northern Japan [PDF]
Acta Palaeontologica Polonica, 2022 Mature modifications, ontogeny, and dimorphism of the small-sized tetragonitid ammonoid Tetragonites minimus were investigated in 43 specimens from the Santonian, Upper Cretaceous of the northwestern area of Hokkaido, Japan.
DAISUKE AIBA
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The dorsal shell wall structure of Mesozoic ammonoids [PDF]
Acta Palaeontologica Polonica, 2017 The study of pristine preserved shells of Mesozoic Ammonoidea shows different types of construction and formation of the dorsal shell wall. We observe three major types: (i) The vast majority of Ammonoidea, usually planispirally coiled, has a prismatic ...
Gregor Radtke, Helmut Keupp
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Papers in Palaeontology, Volume 7, Issue 3, Page 1435-1457, August 2021., 2021 Abstract The ammonoid genus Arctoceras (Hyatt) occurs across all palaeolatitudes, and is a key genus for middle Smithian biostratigraphical correlations globally. In this study, intraspecific variations in conch morphology, ornamentation and allometry are examined in relation to stratigraphic position.
Bitten B. Hansen +4 more
wiley +1 more source
Recent advances in heteromorph ammonoid palaeobiology
Biological Reviews, Volume 96, Issue 2, Page 576-610, April 2021., 2021 ABSTRACT Heteromorphs are ammonoids forming a conch with detached whorls (open coiling) or non‐planispiral coiling. Such aberrant forms appeared convergently four times within this extinct group of cephalopods. Since Wiedmann's seminal paper in this journal, the palaeobiology of heteromorphs has advanced substantially.
René Hoffmann +9 more
wiley +1 more source
Early Cretaceous ammonites and dinoflagellates from the Western Tatra Mountains, Poland [PDF]
Acta Palaeontologica Polonica, 2020 The first Early Cretaceous (Valanginian–Hauterivian) ammonite fauna from the lower part of the Kościeliska Marl Formation (Wściekły Żleb Member) of the Lower Sub-Tatric (Krížna) Nappe, in the Lejowa Valley of the Tatra Mountains are described.
Zdeněk Vašíček +6 more
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Acta Palaeontologica Polonica, 2023 Fossils of Devonian ammonoids are abundant and well-preserved in the Anti-Atlas of Morocco; as such they provide an invaluable record of regional morphological disparity changes (diversity of shapes) that characterise the first steps of ammonoid ...
NINON ALLAIRE +6 more
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Conellae, enigmatic structures on cephalopod shells—shapes, distribution, and formation [PDF]
Acta Palaeontologica Polonica, 2019 Conellae, enigmatic cone-shaped structures which can be found on the surface of internal moulds of cephalopod shells (predominantly of ammonoids), are regarded herein as the product of remote (biologically induced) biomineralization formed in closed-off ...
René Hoffmann +2 more
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