Taphonomic patterns mimic biologic structures: diagenetic Liesegang rings in Mesozoic coleoids and coprolites

Christian Klug; Gianpaolo Di Silvestro; Rene Hoffmann; Guenter Schweigert; Dirk Fuchs; Thomas Clements; Pierre Gueriau

doi:10.7717/peerj.10703

Taphonomic patterns mimic biologic structures: diagenetic Liesegang rings in Mesozoic coleoids and coprolites

PeerJ. 2021 Jan 14:9:e10703. doi: 10.7717/peerj.10703. eCollection 2021.

Authors

Christian Klug¹, Gianpaolo Di Silvestro², Rene Hoffmann³, Guenter Schweigert⁴, Dirk Fuchs⁵, Thomas Clements⁶, Pierre Gueriau⁷

Affiliations

¹ Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland.
² Trilobite Design Italia, Aurisina (TS), Italy.
³ Institute of Geology, Mineralogy & Geophysics, Ruhr-Universität Bochum, Bochum, Germany.
⁴ Staatliches Museum für Naturkunde, Stuttgart, Germany.
⁵ Bayerische Staatssammlung für Paläontologie und Geologie, München, Germany.
⁶ School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.
⁷ Institute of Earth Sciences (ISTE), University of Lausanne, Lausanne, Switzerland.

Abstract

Because of physiology of coleoids, their fossils preserve soft-tissue-remains more often than other cephalopods. Sometimes, the phosphatized soft-tissues, particularly parts of the muscular mantle, display dark circular patterns. Here, we showcase that these patterns, here documented for fossil coleoids from the Jurassic of Germany and the Cretaceous of Lebanon, superficially resemble chromatophores (which enable living coleoids to alter their coloration). We examined and chemically analyzed the circular structures in these specimens, describe them, and discuss their genesis. Based on their structure and color, we visually differentiate between three types of circles. By comparison with similar structures, we suggest that these structures are not biogenic but Liesegang rings, which formed due to reaction-diffusion processes very soon after death.

Keywords: Coleoidea; Conservation deposits; Cretaceous; Diagenesis; Exceptional preservation; Jurassic; Vampyropoda.

Grants and funding

This research was supported by the Swiss National Science Foundation SNF (grant 200021_169627). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.