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Article: Ontogenetic trajectories of septal spacing in Early Jurassic belemnites from Germany and France, and their palaeobiological implications

Palaeontology Cover Image - Volume 61 Part 1
Publication: Palaeontology
Volume: 61
Part: 1
Publication Date: January 2018
Page(s): 77 88
Author(s): Ryoji Wani, Amane Tajika, Kenji Ikuno, and Tetsuro Iwasaki
Addition Information

How to Cite

WANI, R., TAJIKA, A., IKUNO, K., IWASAKI, T. 2018. Ontogenetic trajectories of septal spacing in Early Jurassic belemnites from Germany and France, and their palaeobiological implications. Palaeontology, 61, 1, 77-88. DOI: 10.1111/pala.12327

Author Information

  • Ryoji Wani - Faculty of Environment & Information Sciences Yokohama National University Yokohama Japan (Email: wani@ynu.ac.jp)
  • Amane Tajika - Paläontologisches Institut und Museum Universität Zürich Zürich Switzerland
  • Kenji Ikuno - Graduate School of Environment & Information Sciences Yokohama National University Yokohama Japan
  • Kenji Ikuno - Division of Natural History Museum of Nature & Human Activities Hyogo Sanda Japan
  • Kenji Ikuno - Division of Earth Sciences Institute of Natural & Environmental Sciences University of Hyogo Sanda Japan
  • Tetsuro Iwasaki - Graduate School of Environment & Information Sciences Yokohama National University Yokohama Japan

Publication History

  • Issue published online: 25 December 2017
  • Manuscript Accepted: 20 August 2017
  • Manuscript Received: 11 May 2017

Funded By

Grant‐in‐Aid for Young Scientists, Japan Society for the Promotion of Science. Grant Number: 26800264

Online Version Hosted By

Wiley Online Library (Free Access)
Get Article: Wiley Online Library [Free Access]

Abstract

Based on well‐preserved belemnites, the ontogenetic trajectories of septal spacing between succeeding chambers were analysed. In the examined species (Passaloteuthis laevigata, Parapassaloteuthis zieteni and Pseudohasitites longiformis) that come from Buttenheim, Germany, and Lixhausen, France, the ontogenetic trajectories of septal spacing follow exponentially increasing trends with no decreasing phase of septal crowding during the earliest ontogenetic stage. The absence of a decreasing trend at the earliest ontogenetic stage is a unique character in contrast with those in modern cuttlefish and ancient and modern nautiloids, in which the decreasing trends are related to hatching events. These ontogenetic septal spacing trends suggest that the belemnite hatchlings had only a protoconch with no chamber. These belemnite hatchlings with no chamber and therefore small embryonic shell diameter are similar to those of ammonoids. Significant difference in a statistical test that compared the protoconch size between the two localities, might suggest that there was limited transportation at the embryonic stage, although it could also just indicate differences in regional environmental conditions, age and/or degree of time averaging which might differ between the examined taxa.

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