Integrating 2D and 3D shell morphology to disentangle the palaeobiology of ammonoids: a virtual approach

• DOI: 10.1111/pala.12328
• Publication Date: 2017-10-12T04:18:40Z
• Authors: René Hoffmann; Robert E. Lemanis; Janina Falkenberg; Steffen Schneider; Hendrik Wesendonk; Stefan Zachow
• Keywords: Ammonite; Ammonoidea; Morphology; Paleobiology

Abstract Based on data derived from computed tomography, we demonstrate that integrating 2D and 3D morphological ammonoid shells represents an important new approach for investigating the palaeobiology of ammonoids. Characterization ammonite morphology has long been constrained to data, with only a few studies collecting ontogenetic in 180° steps. Here combine this traditional collected high‐resolution nano‐computed tomography. Ontogenetic hollow shell juvenile Kosmoceras (Jurassic, Callovian) was collected. 10° steps show significant changes morphology. Preserved spines multiple mineralized membranes never reported before, representing temporal mantle tissue. chamber volumes do not always increase exponentially, as generally assumed, but may represent proxy life events, such stress phases. Furthermore, volume cannot be simply septal spacing forms comparable . Vogel numbers parameter shape, those are similar other ammonoids ( Arnsbergites , Amauroceras ) modern cephalopods Nautilus Spirula ). Two methods virtually document suture line ontogeny, used phylogenetic relationships larger taxonomic entities, were applied first time present promising alternative hand drawings. The curvature surfaces increases during ontogeny due increasing strength ornamentation complexity. As allow faster handling cameral liquid, it could compensate decreasing SA /V ratios through ontogeny.