論文

査読有り 筆頭著者
2018年

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

Palaeontology
  • Ryoji Wani
  • ,
  • Amane Tajika
  • ,
  • Kenji Ikuno
  • ,
  • Tetsuro Iwasaki

61
1
開始ページ
77
終了ページ
88
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1111/pala.12327
出版者・発行元
Blackwell Publishing Ltd

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.

リンク情報
DOI
https://doi.org/10.1111/pala.12327
ID情報
  • DOI : 10.1111/pala.12327
  • ISSN : 1475-4983
  • ISSN : 0031-0239
  • SCOPUS ID : 85039063626

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