English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Understanding the hydrostatic properties of ectocochleate cephalopods is essential to study the functional morphology of their shells. The conditions for neutral buoyancy, static orientation of the living animal, and their hydrostatic stability are key factors to determine the physical relationships and constraints on cephalopod life habits and paleoecology. The hydrostatics of early orthoconic and cyrtoconic Paleozoic cephalopods were investigated by digitally reconstructing morphotypes within Nautiloidea and Endoceratoidea. Morphotypes were chosen from several traditional orders and include endogastric cyrtocones (Ellesmerocerida and Discosorida), exogastric cyrtocones (Oncocerida), and longi-orthocones (Orthocerida and Endocerida). The extant nautilid, Nautilus pompilius, was also modeled as a reference for the hydrostatics of the Paleozoic cephalopods. All cyrtocone models have similar hydrostatic stability to the Nautilus and only the ellesmerocerid was found to be negatively buoyant. The hydrostatics of the neutrally buoyant cyrtocones suggests that they behaved as relatively poor-swimming demersal or nekto-benthic predators. This mode of life aligns with the largely neritic distribution of individuals belonging to these clades in the Paleozoic. In contrast, the orthocones studied were all capable of neutral buoyancy, much more stable than the Nautilus model, and all had vertical syn vivo orientations in a static setting. The hydrostatic properties of these morphotypes and their largely pelagic distribution support their role as vertical migrants. However, adapically distributed cameral deposits and endosiphuncular deposits would reduce stability, easing deviation from a vertical orientation. These adaptations, along with dorsal color patterns on some species, suggest that active locomotion in orthocones may have been more important than previously thought. David J. Peterman. Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, United States of America. peterman.10@wright.edu PETERMAN, BARTON, & YACOBUCCI: CEPHALOPOD HYDROSTATICS 2 Christopher C. Barton. Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, United States of America. chris.barton@wright.edu Margaret M. Yacobucci. Department of Geology, Bowling Green State University, Bowling Green, Ohio, United States of America. mmyacob@bgsu.edu

palaeontologia electronica

The hydrostatics of Paleozoic ectocochleate cephalopods (Nautiloidea and Endoceratoidea) with implications for modes of life and early colonization of the pelagic zone