Year-end Sale % OFF 
Abstract
Although belemnite rostra can be quite abundant in Jurassic and Cretaceous strata, the record of belemnite jaws was limited to a few specimens from Germany and Russia. Here, we describe and figure three cephalopod jaws from the Middle Jurassic Opalinus Clay of northern Switzerland. Although flattened, the carbonaceous fossils display enough morphological information to rule out an ammonoid, nautiloid or octobrachian origin of the two larger jaws. Their similarities to belemnite jaws from Germany and Russia conforms with our interpretation of these specimens as belemnite jaws. Based on their rather large size, we tentatively assign these two jaws to the megateuthidid Acrocoelites conoideus. The third jaw is a rather small upper jaw of an ammonoid. Since Leioceras opalinum is by far the most common ammonite in this unit in northern Switzerland, we tentatively suggest that the upper jaw belongs to this species.
Highlights
Belemnites are extinct coleoid cephalopods, i.e., relatives of modern squids, cuttlefishes and octopuses (Fuchs 2006; Kröger et al 2011; Iba et al 2012, 2014; Klug et al 2016; Hoffmann et al 2016, 2020; Hoffmann and Stevens 2020)
Fossil coleoid jaws are poorly known globally. This is mainly due to their chitinous composition, which results in a significantly lower fossilization potential compared to mineralized carbonaceous hardparts (Nixon 2015; Donovan and Fuchs 2016)
Since Leioceras opalinum is by far the most common species accounting with micro- and macroconchs for well over 95% of the ammonite specimens, we suggest that PIMUZ 5942 represents the upper jaw of this index ammonoid
Summary
Belemnites are extinct coleoid cephalopods, i.e., relatives of modern squids, cuttlefishes and octopuses (Fuchs 2006; Kröger et al 2011; Iba et al 2012, 2014; Klug et al 2016; Hoffmann et al 2016, 2020; Hoffmann and Stevens 2020). The first belemnite jaws revealing some more morphological information come from the Kimmeridgian of Nusplingen, Germany (for stratigraphic and locality details, see Klug et al 2010b). This specimen (SMNS 67335) was assigned to Hibolithes, the most common species in these strata.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
