<abstract xmlns="http://www.w3.org/1999/xhtml">

<p><italic>As yet undescribed accumulations of shells of orthoconic cephalopods, which are in some aspects comparable to cephalopod limestones known from the Silurian and Lower Devonian of the Barrandian area and other regions of the world, occur in the Letná and Zahořany formations (middle Sandbian and lower Katian stages, Upper Ordovician, central Bohemia). These accumulated shells are often colonized by sessile organisms. Only a small proportion of these organisms could be attached to shells of alive cephalopods; the majority of them used empty shells as solid substrates. The most abundant epizoan is the cystosporate bryozoan of the genus</italic> Ceramopora <italic>that often overgrows the cephalopod shells extensively. Holdfasts of the genus</italic> Sphenothallus <italic>and problematic fossils assigned to the genus</italic> Conchicolites <italic>are common. Rarer epibionts include the bryozoan</italic> Spatiopora, <italic>the cystoid echinoderm</italic> Codiacystis <italic>and the brachiopod</italic> Ptychopeltis. <italic>Varying sizes of bryozoan colonies occurring on the same cephalopod shell point to several recurring attachment events, probably reflecting reproduction cycles.</italic></p>
</abstract>

As yet undescribed accumulations of shells of orthoconic cephalopods, which are in some aspects comparable to cephalopod limestones known from the Silurian and Lower Devonian of the Barrandian area and other regions of the world, occur in the Letná and Zahořany formations (middle Sandbian and lower Katian stages, Upper Ordovician, central Bohemia). These accumulated shells are often colonized by sessile organisms. Only a small proportion of these organisms could be attached to shells of alive cephalopods; the majority of them used empty shells as solid substrates. The most abundant epizoan is the cystosporate bryozoan of the genus Ceramopora that often overgrows the cephalopod shells extensively. Holdfasts of the genus Sphenothallus and problematic fossils assigned to the genus Conchicolites are common. Rarer epibionts include the bryozoan Spatiopora, the cystoid echinoderm Codiacystis and the brachiopod Ptychopeltis. Varying sizes of bryozoan colonies occurring on the same cephalopod shell point to several recurring attachment events, probably reflecting reproduction cycles.

Accumulations of Fossil Cephalopod Shells and Attached Epizoans from Some Late Ordovician Localities (Barrandian Area, Czech Republic)

Folia Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

As yet undescribed accumulations of shells of orthoconic cephalopods, which are in some aspects comparable to cephalopod limestones known from the Silurian and...

Accumulations of Fossil Cephalopod Shells and Attached Epizoans from Some Late Ordovician Localities (Barrandian Area, Czech Republic)

Publié en ligne: 19 mai 2024

Pages: 11 - 42

DOI: https://doi.org/10.2478/fbgp-2023-0002

Mots clés
Sandbian, Katian, Letná Formation, Zahořany Formation, orthoconic cephalopods

© 2023 Jaroslav Marek et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Accumulations of Fossil Cephalopod Shells and Attached Epizoans from Some Late Ordovician Localities (Barrandian Area, Czech Republic)

Publié en ligne: 19 mai 2024

Pages: 11 - 42

DOI: https://doi.org/10.2478/fbgp-2023-0002

Mots clésSandbian, Katian, Letná Formation, Zahořany Formation, orthoconic cephalopods

© 2023 Jaroslav Marek et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Mots clés
Sandbian, Katian, Letná Formation, Zahořany Formation, orthoconic cephalopods