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Structure of dolphin shoulder musculature and its phylogenetical implication

Research Project

Project/Area Number 08640900
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 系統・分類
Research InstitutionNational Science Museum

Principal Investigator

YAMADA Tadasu K.  National, Science Museum, Department of Zoology, Curator in Chief, 動物研究部, 室長 (70125681)

Project Period (FY) 1996 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1998: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1997: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1996: ¥900,000 (Direct Cost: ¥900,000)
KeywordsCetacea / Odontoceti / Myology / Panniculus carnosus / Trapezius muscle / Phylogeny / Accessory nerve / Comparative Anatomy
Research Abstract

The aims at obtaining good understanding of dolphin shoulder musculature in the light of phylogenetical investigations and considerations, During the course of research I found the astounding fact that most of the former works contain several erroneous descriptions. Therefore, I made more detailed descriptions on the Delphinidae shoulder musculature including data on the nerves of innervation. The result were compared with terrestrial mammalian shoulder muscles and I reached interesting results.
Materials : 2 common dolphins (Delphinus delphis), 3 bottlenose dolphins (Tursiops truncatus), 1 Pacific white sided dolphin (Lagenorhynchus obliquidens) and 1 melon headed dolphin (Peponocephala electra).
Findings : Dolphin species examined have the trapezius muscle (two portions) although Strickler (1976) stated that the odontocetes have no trapezius. Their plexus contain nerve bundles from 7 spinal segments (04 through Th1) and a little contribution from 03. Nerves recognized as ventral member … More s were : supra scapular (03-6), phrenic(03-6), cranial pectoral (03-6), musculo cutaneous (05-Th1), intermedial pectoral (05-Th1), median (05-Th1) ulnar (05-Th1), caudal pectoral (05-Th1), while in the dorsal group were subscapular (05-Th1), axillary (05-Th1), radial (05-Th1), thoracodorsal (05-Th1).
Discussion : Comparing these findings with data on the terrestrial mammals it is striking that the basic structure is more resembled with human' condition. The dorso-ventral gradients among those nerves are fundamentally identical to those of terrestrial mammals. Remarkably, number of muscles is more similar to humans rather than the other terrestrial quadruped mammals. This can be so because forelimbs of the terrestrial mammals are for supporting the weight of cranial portion of the body whereas in humans and dolphins anterior extremities are free from weight bearing and more freedom in the forelimb movement is more important for these animals. In conclusion, dolphins and humans are both more like groups of mammals with structure of shoulder more suitable for much more free movement. We should consider these animals with more exact understanding on their body structure. Less

Report

(4 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • 1996 Annual Research Report
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 山田 格ほか: "イルカ・クジラの解剖学-これからの領域-" 月 刊 海 洋. 30・9. 524-529 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Yamada,T.K.,et al.: "Is there no Trapezius in dolphins?" Journal of Morphology. 323・3. 343- (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Yamada, Tadasu K.: "Anatomy of dolphins and whales a research field to be studied more." Kaiyo Monthly. 30-9. 524-529 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Yamada, T.K., et al: "Is there no Trapezius in dolphins?" Journal of Morphology. 323-3. 343 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] 山田格、伊藤春香、高倉ひろか: "イルカ・クジラの解剖学-これからの領域-" 月刊海洋. 30(9). 524-529 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] Yamada,T.K.,Ito,H.,and Takakura,H.: "On the dolphin shoulder muscles,with special reference to their nerves of supply." Twelfth Biennial Conference of the Biology of Marine Mammals,Abstracts. 152 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] Yamada,T.K., H.Ito & H.Takakura: "Is there no Trapezius in dolphins?" Journal of Morphology. 332 (3). 343 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] Yamada,T.K.,Ito,H.& Takakura,H.: "Is there no Trapezius in dolphins?" Journal of Morphology. Vol.231(June 未定).

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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