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A rare coleoid mollusc from the Upper Jurassic of Central Russia

100%
Doguzhaeva L. A.
Acta Palaeontologica Polonica
|
2000
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tom 45
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nr 4
The shell of the coleoid cephalopod mollusc Kostromateuthis roemeri gen. et sp. n. from the lower Kimmeridgian of Central Russia consists of the slowly expanding orthoconic phragmocone and aragonitic sheath with a rugged surface, a weakly developed post-alveolar part and a long, strong, probably dorsal groove. The sheath lacks concentric structure common for belemnoid rostra. It is formed by spherulites consisting of the needle-like crystallites, and is characterized by strong porosity and high content of originally organic matter. Each spherulite has a porous central part, a solid periphery and an organic cover. Tubular structures with a wall formed by the needle-like crystallites are present in the sheath. For comparison the shell ultrastructure in Recent Spirula and Sepia, as well as in the Eocene Belemnosis were studied with SEM. Based on gross morphology and sheath ultrastructure K. roemeri is tentatively assigned to Spirulida and a monotypic family Kostromateuthidae nov. is erected for it. The Mesozoic evolution of spirulids is discussed.
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Triassic coleoid beaks and other structures from the Calcareous Alps revisited

80%
Doguzhaeva L. A., Summesberger H., Brandstaetter F., Gruber D., Tintori A.
Acta Palaeontologica Polonica
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2022
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tom 67
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nr 3
3
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Late Cretaceous record of large soft-bodied coleoids based on lower jaw remains from Hokkaido, Japan

80%
Tanabe K., Misaki A., Ubukata T.
Acta Palaeontologica Polonica
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2015
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tom 60
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nr 1
The origin and phylogenetic relationships of most modern coleoid groups have not yet been explained by reliable fossil evidence, in large part because of the reduction or disappearance of a calcified chambered shell during their evolutionary history. Herein we describe two exceptionally large coleoid lower jaws from the Upper Cretaceous strata in Hokkaido, Japan. On the basis of the comparison of gross morphology and morphometric data of the lower jaws of modern and fossil coleoids, we assigned the two lower jaws to the following new taxa: Nanaimoteuthis hikidai sp. nov. of the order Vampyromorpha (superorder Octobrachia) and Haboroteuthis poseidon gen. et sp. nov. of the order Teuthida (superorder Decabrachia). The lower jaw of N. hikidai is distinguished from other species of the same genus from the Upper Cretaceous of Vancouver Island (Canada) and Hokkaido by having a broader, more anteriorly curved hood of the outer lamella. The lower jaw of H. poseidon seemingly exhibits mosaic features like those of modern teuthids and sepiids but is assigned to Teuthida on the basis of the overall shape of the outer lamella and the development of a distinct fold on the lateral wall. Because of the unusually large lower jaws, these new taxa appear to be comparable in body size to modern giant squids (Architeuthis spp.) and the Humboldt squid (Dosidicus gigas). This and other discoveries of large jaws referable to octobrachian and decabrachian coleoids from the Upper Cretaceous strata of the North Pacific fill the gap in the relatively poor fossil record of mainly soft-bodied coleoids.
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Gladius shape variation in coleoid cephalopod Trachyteuthis from the Upper Jurassic Nusplingen and Solnhofen Plattenkalks

80%
Fuchs D., Engeser T., Keupp H.
Acta Palaeontologica Polonica
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2007
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tom 52
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nr 3
Although the fossil record of coleoid cephalopods is generally poor, the Upper Jurassic Nusplingen and Solnhofen Plattenkalks have provided numerous well−preserved coleoids. Trachyteuthis hastiformis, a comparatively large vampyropod coleoid, was previously known to represent the sole species of its genus in Nusplingen and Solnhofen. However, morphological comparisons based on 50 specimens from different museum collections revealed two additional species: T. nusplingensis sp. nov. and T. teudopsiformis sp. nov. Both species lack the distinct spindle−shaped elevation on the gladius median field typical for T. hastiformis. T. nusplingensis sp. nov. is clearly characterised by a smooth median field and a more or less regular granulation on the dorsal gladius surface, whereas T. teudopsiformis sp. nov. can be easily distinguished by the presence of a Teudopsis−like median keel and an extremely narrow granulation. Morphometric analyses have shown that length−width indices are ambiguous characters to differentiate between the three species. Phylogenetically, the keeled and anteriorly pointed T. teudopsiformis sp. nov. can be linked with the Early Jurassic genus Teudopsis and the Late Cretaceous genus Glyphiteuthis.
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