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サメ類の胎生はなぜ獲得されたのか : サメ類の生殖システムの進化

Research Project

Project/Area Number 11J05588
Research Category

Grant-in-Aid for JSPS Fellows

Allocation TypeSingle-year Grants
Section国内
Research Field Stratigraphy/Paleontology
Research InstitutionHokkaido University

Principal Investigator

冨田 武照  北海道大学, 総合博物館, 特別研究員(PD)

Project Period (FY) 2011 – 2013
Project Status Completed (Fiscal Year 2013)
Budget Amount *help
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2013: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2012: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2011: ¥800,000 (Direct Cost: ¥800,000)
Keywords進化 / 生殖 / 呼吸 / 板鰓類 / 軟骨魚類 / 胎生 / 卵生 / 生殖様式 / マンタ
Research Abstract

サメ・エイ類を含む軟骨魚類は、現在でも生きている原始的な脊椎動物と考えられており、その生殖システムを解明することは私たちの生殖システムの起源を知る上で極めて重要である。特にサメ・エイ類には卵生(卵を産む)と胎生(赤ちゃんを産む)のグループが共存しており、私たち哺乳類に見られる胎生がいかに進化してきたのか明らかにする格好の材料である。私は、沖縄美ら海水族館と共同で、卵生のトラザメが呼吸システムをいかに獲得するのか詳細に調査を行った。調査には実体顕微鏡による行動解析、組織切片の観察などを中心に行った。その結果、トラザメの胎児は卵殻の中にいる期間に大きく呼吸システムを変化させることが明らかになった。具体的には、前半の期間には外鰓を用いて呼吸を行うが、後半の期間には筋肉や骨格系の発達に伴って水をポンピングする能力を獲得し、内鰓を用いて呼吸を行うようになる。このような呼吸システムの変化は脊椎動物の進化の初期にすでに獲得されていた可能性がある。さらに、私の過去の胎生のエイ類の研究によって得られた結果は、トラザメで見られた呼吸システムの変化は胎生のサメ・エイ類でも見られる可能性があることを示している。この結果は、卵生と胎生はまったく異なる生殖システムなのではなく、ある程度同じシステムを共有していることを示唆している。胎生と卵生のシステムに今回共通性が見出せたことで、卵生から胎生への進化の過程の一端が解明できたと評価できる。

Strategy for Future Research Activity

(抄録なし)

Report

(3 results)
  • 2013 Annual Research Report
  • 2012 Annual Research Report
  • 2011 Annual Research Report
  • Research Products

    (14 results)

All 2014 2013 2012 2011

All Journal Article (9 results) (of which Peer Reviewed: 9 results) Presentation (5 results) (of which Invited: 1 results)

  • [Journal Article] Northernmost record of a whale shark Phincodon typus from the Sea of Okhotsk2014

    • Author(s)
      Taketeru tomita, Toshio Kawai, Hajime Matsubara, Mari Kobayashi, and Seiji Katakura
    • Journal Title

      Journal of Fish Biology

      Volume: 84 Issue: 1 Pages: 243-246

    • DOI

      10.1111/jfb.12273

    • Related Report
      2013 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Pectoral fin of the megamouth shark : skeletal and muscular systems, skin histology, and functional morphology2014

    • Author(s)
      Taketeru Tomita, Sho Tanaka, Keiichi Sato, and Kazuhiro Nakaya
    • Journal Title

      PLOS ONE

      Volume: 9 Issue: 1 Pages: e86205-e86205

    • DOI

      10.1371/journal.pone.0086205

    • Related Report
      2013 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Evolutionary relations of Hexanchiformes deep-sae sharks elucidated by whole mitochondrial genome sequences2013

    • Author(s)
      Keiko Tanaka, Takashi Shiina, Taketeru Tomita, Shingo Suzuki, Kazuyoshi Hosomichi, Kuzumi Sano, Hiroyuki Doi, Azumi Kono, Tomoyoshi Komiyama, Hidetoshi Inoko, Jerzy K. Kulski, and Sho Tanaka
    • Journal Title

      BioMed Research Ineternational

      Volume: 2,013 Pages: 1-11

    • DOI

      10.1155/2013/147064

    • Related Report
      2013 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobanchii : Batoidea : Myliobatiformes) in the Sea of Okhotsk : first record from cold temperate waters2013

    • Author(s)
      Taketeru Tomita, Toshio Kawai, Hajime Matsubara, and Ryuichi Nagata
    • Journal Title

      journal of Fish Biology

      Volume: 83 Issue: 3 Pages: 695-698

    • DOI

      10.1111/jfb.12205

    • Related Report
      2013 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Absence of suction feeding Ichthyosaurs and its implications for Triassic mesopelagic paleoecology2013

    • Author(s)
      Ryosuke Motani, cheng Ji, Taketeru Tomita, Neil Kelley, Erin Maxwell, Da-yong Jiang, Paul Martin Sander
    • Journal Title

      PLOS ONE

      Volume: 8 Issue: 12 Pages: e66075-e66075

    • DOI

      10.1371/journal.pone.0066075

    • Related Report
      2013 Annual Research Report
    • Peer Reviewed
  • [Journal Article] A novel pharyngeal expansion mechanism in the yellow-spotted fanray, Platyrhina tangi (Elasmobranchii : Batoidea), with special reference to the function of the fifth ceratobranchial cartilage in batoids.2013

    • Author(s)
      Tomita, T., Toda, M., Yamamoto, Y. , Sato, K., Uchida, S. , and Nakaya, K.
    • Journal Title

      Zoomorphology

      Volume: (online first) Issue: 3 Pages: 317-324

    • DOI

      10.1007/s00435-012-0185-9

    • Related Report
      2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Live-bearing manta ray : how the embryo acquires oxygen without placenta and umbilical cord.2012

    • Author(s)
      Tomita, T., Toda, M., Ueda, K., Uchida, S., and Nakaya, K.
    • Journal Title

      Biology Letters

      Volume: 8 Issue: 5 Pages: 721-724

    • DOI

      10.1098/rsbl.2012.0288

    • Related Report
      2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Mouth-Size Estimation of a Primitive Lamiform Shark, Protolamna : Low Trophic Position in Lamiform Shark Origin2011

    • Author(s)
      Tomita, T.
    • Journal Title

      Paleontological Research

      Volume: 15 Issue: 2 Pages: 68-76

    • DOI

      10.2517/1342-8144-15.2.068

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] First Record of a Large Lamniform Shark Cretodus semiplicatus in the Pacific Region, from the Mikasa Formation (Lower Cenomanian), Hokkaido, Japan2011

    • Author(s)
      Tomita, T., Kurihara, K.
    • Journal Title

      Paleontological Research

      Volume: 15 Pages: 181-184

    • Related Report
      2011 Annual Research Report
    • Peer Reviewed
  • [Presentation] Megamouth Shark---Function and Anatomy2013

    • Author(s)
      Taketeru Tomita
    • Organizer
      International Symposium : The filter feeding elasmobranchs : Unraveling their many mysteries
    • Place of Presentation
      沖縄美ら海水族館(沖縄県)
    • Year and Date
      2013-06-29
    • Related Report
      2013 Annual Research Report
    • Invited
  • [Presentation] A novel pharyngeal expansion mechanism in the yellow-spotted fanray, Platyrhina tangi2013

    • Author(s)
      Taketeru Tomita, Minoru Toda, Yushi Yamamoto, Keiichi Sato, Senzo Uchida, and Kazuhiro Nakaya
    • Organizer
      Indo Pacific Fish Conference
    • Place of Presentation
      沖縄コンベンションセンター(沖縄県)
    • Year and Date
      2013-06-25
    • Related Report
      2013 Annual Research Report
  • [Presentation] Absence of suction feeders among Ichthyosaurus and importance of mechanism-based quatification in functional inferences.2012

    • Author(s)
      Motani, R. Ji, C, Tomita, T. and Jiang, D.
    • Organizer
      Society of Vertebrate Paleontology
    • Place of Presentation
      North Carolina State University (USA)
    • Year and Date
      2012-10-17
    • Related Report
      2012 Annual Research Report
  • [Presentation] Feeding of the megamouth shark (Pisces : Lamniformes : Megachasmidae) predicted by its hyoid arch : a biomechanical approach2012

    • Author(s)
      Tomita, T., Sato, K. , Suda, K., Kawauchi, J. , and Nakaya, K. 2011.
    • Organizer
      World congress of Herpetology
    • Place of Presentation
      University of British Columbia (カナダ)
    • Year and Date
      2012-08-10
    • Related Report
      2012 Annual Research Report
  • [Presentation] 鱗のリブレット効果に基づく化石サメ類の遊泳速度の推定2011

    • Author(s)
      冨田武照
    • Organizer
      日本古生物学会
    • Place of Presentation
      金沢大学(金沢市)
    • Year and Date
      2011-06-15
    • Related Report
      2011 Annual Research Report

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Published: 2011-12-12   Modified: 2024-03-26  

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