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Ammonoid dilemma: functional trade-off between weight saving and shell strength

Research Project

Project/Area Number 17K05693
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Stratigraphy/Paleontology
Research InstitutionKyoto University

Principal Investigator

Ubukata Takao  京都大学, 理学研究科, 教授 (00293598)

Project Period (FY) 2017-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywordsアンモナイト / 外殻性頭足類 / 機能形態 / 静水力学 / 流体力学 / 殻強度 / トレードオフ / 形態空間 / アンモノイド / 姿勢の安定性 / 搖動 / オウムガイ / パレート最適 / 比表面積
Outline of Final Research Achievements

Ammonoids have a chambered conch that serves as a buoyancy apparatus, and hydrostatic and hydrodynamic properties that depend on conch geometry may be critical for their locomotion. Meanwhile, the shell wall should be mechanically strong enough to support the conch against hydrostatic pressure. The present analyses using a theoretical morphologic model revealed a functional trade-off between hydrostatic and hydrodynamic efficiencies. A positive correlation between relative shell thickness and hydrostatic efficiency found in this study suggests that density control was critical for ammonoids and a hydrodynamically efficient shell shape is hardly realized without sacrificing shell strength. The morphometric result shows the followings: 1) prolecanitids tend to be optimized for hydrodynamic efficiency, but some goniatitids seem to be inefficient for nektonic mode of life; 2) nautilids are optimized for hydrostatic efficiency, while tarphycerids tend to be optimized for postural stability.

Academic Significance and Societal Importance of the Research Achievements

アンモナイトの流体力学特性に関する研究は半世紀にわたる歴史を有するが,なぜアンモナイトの殻形態が遊泳に適した究極の流線形に収斂せず,多様な殻形態が見られるのかが議論されてきた.一方,静水力学特性や殻の強度,殻形成効率など幾つかの観点から機能形態学的研究が進められてきたが,アンモナイトの形態的多様性はそれら異なる機能への適応の結果として理解されてきた.本研究は,そうした従来の定性的な解釈を踏まえて,アンモナイトあるいは外殻性頭足類の形態的多様性が,想定される機能的要請の折衷戦略としてある程度説明できることを,機能-形態空間解析の方法によって分析的に示した.

Report

(4 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • 2017 Research-status Report
  • Research Products

    (20 results)

All 2020 2019 2018 2017

All Presentation (20 results) (of which Int'l Joint Research: 4 results,  Invited: 4 results)

  • [Presentation] アンモノイドの殻形状の個体発生変異を表す理論形態モデル2020

    • Author(s)
      生形貴男
    • Organizer
      日本古生物学会第168会例会
    • Related Report
      2019 Annual Research Report
  • [Presentation] 正常巻頭足類のロッキング運動への殻形状の影響2019

    • Author(s)
      生形貴男
    • Organizer
      日本地球惑星科学連合2019年大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] 古生物の形態と形態的多様性の解析:貝類化石の例2019

    • Author(s)
      生形貴男
    • Organizer
      現象数理学研究拠点共同研究集会
    • Related Report
      2019 Annual Research Report
    • Invited
  • [Presentation] アンモノイドの殻形状の個体発生軌道の系統性2019

    • Author(s)
      生形貴男
    • Organizer
      日本地質学会第124年学術大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] Functional trade-off between hydrostatic and hydrodynamic efficiencies of shell form in ectoconchlete cephalopods2019

    • Author(s)
      Ubukata, T.
    • Organizer
      1st Asian Palaeontological Congress
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] 外殻性頭足類の静水力学的形状特性と流体力学的形状特性の間の相反関係:生息姿勢を考慮した場合2019

    • Author(s)
      生形貴男
    • Organizer
      日本古生物学会第167会例会
    • Related Report
      2018 Research-status Report
  • [Presentation] アンモノイドにおける静水力学的・流体力学的形状特性と分類群生息期間との関係2018

    • Author(s)
      生形貴男
    • Organizer
      日本地球惑星科学連合2018年大会
    • Related Report
      2018 Research-status Report
  • [Presentation] アンモノイドにおける形態的異質性と分類学的多様性の関係の変遷2018

    • Author(s)
      生形貴男
    • Organizer
      日本地球惑星科学連合2018年大会
    • Related Report
      2018 Research-status Report
  • [Presentation] オウムガイ類の殻形態の多様性は比表面積に制約される2018

    • Author(s)
      生形貴男
    • Organizer
      日本古生物学会2018年年会
    • Related Report
      2018 Research-status Report
  • [Presentation] Assessment of morphological richness in morphospace: a case study for analysis of disparity in ammonoids2018

    • Author(s)
      Takao Ubukata
    • Organizer
      5th International Palaeontological Congress
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] From morphospace to macroevolution: large-scale morphological analyses of molluscan shells2018

    • Author(s)
      Takao Ubukata
    • Organizer
      Joit Meeting on the 12th National Congress of the Palaeontological Society of China
    • Related Report
      2018 Research-status Report
    • Invited
  • [Presentation] アンモノイドの殻彫刻が比表面積に及ぼす影響2018

    • Author(s)
      生形貴男
    • Organizer
      日本地質学会第123年学術大会
    • Related Report
      2018 Research-status Report
  • [Presentation] 数理を用いた古生物の形態解析2018

    • Author(s)
      生形貴男
    • Organizer
      第34回国際生物学賞記念シンポジウム初期生命の進化
    • Related Report
      2018 Research-status Report
    • Invited
  • [Presentation] アンモノイドの静水力学的形状特性と流体力学的形状特性の変遷2018

    • Author(s)
      生形貴男
    • Organizer
      日本古生物学会第167会例会
    • Related Report
      2017 Research-status Report
  • [Presentation] 地質時代毎の古生物の形態的多様性をいかに評価するか2018

    • Author(s)
      生形貴男
    • Organizer
      日本生態学会第65回大会
    • Related Report
      2017 Research-status Report
  • [Presentation] アンモノイドの体房部の体積比と外殻の比表面積の関係2017

    • Author(s)
      生形貴男
    • Organizer
      日本古生物学会2017年年会
    • Related Report
      2017 Research-status Report
  • [Presentation] Morphological turnover of ammonoids across mass extinction events2017

    • Author(s)
      Ubukata, T.
    • Organizer
      IGCP630 Annual Meeting 2017
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] Assessment of amount of morphospace occupation based on coverage-based morphological rarefaction2017

    • Author(s)
      Ubukata, T.
    • Organizer
      5th International Symposium on Biological Shape Analysis
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] 古生物の形態的多様性変動史をいかにして復元するか:アンモノイドの例2017

    • Author(s)
      生形貴男
    • Organizer
      日本進化学会2017年大会
    • Related Report
      2017 Research-status Report
  • [Presentation] 比重から見たアンモノイドの形態的多様性の制約2017

    • Author(s)
      生形貴男
    • Organizer
      日本地質学会第123年学術大会
    • Related Report
      2017 Research-status Report

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Published: 2017-04-28   Modified: 2021-02-19  

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