Marine fauna in the North Pacific area during the latest Mesozoic

• Project/Area Number: 25400502
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: SHIGETA Yasunari 独立行政法人国立科学博物館, 地学研究部, 研究主幹 (30270408)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2015: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 化石 / 白亜紀 / 絶滅 / アンモナイト / 中生代最末期 / 化石層序

Outline of Final Research Achievements

The geological survey in Hokkaido and Alaska reveals that the gaudryceratid and pachydisciid ammonoids are very useful for establishment of high-resolution biochronology of the uppermost Cretaceous in the North Pacific area. The ammonoid species diversity was relatively high (14 species) during the early Maastrichtian, but it was abruptly reduced by nearly half (7 species) in the middle Maastrichtian. Disappearance of inoceramid bivalves occurred in the middle Maastrichtian. These evidences provide an important key for understanding the middle Maastrichtian event.

Research Products

• [Journal Article] Middle and late Campanian (late Cretaceous) ammonoids from the Urakawa area, Hokkaido, northern Japan (2016)
  • Author(s): Yasunari Shigeta, Masataka Izukura, Tomohiro Nishimura, Yukiyasu Tsutsumi
  • Journal Title: Paleontological Research Volume: 20
  • NAID: 40020952452
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Middle and late Maastrichtian (latest Cretaceous) ammonoids from the Akkeshi Bay area, eastern Hokkaido, northern Japan and their biostratigraphic implications (2015)
  • Author(s): Shigeta, Nishimura, Nifuku
  • Journal Title: Paleontological Research Volume: 19 Issue: 2 Pages: 107-127
  • DOI: 10.2517/2014pr034
  • NAID: 40020417786
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] A new species of Anagaudryceras (Ammonoidea, Gaudryceratidae) from the lowest Maastrichtian of Hokkaido, Japan (2014)
  • Author(s): Shigeta, Nishimura
  • Journal Title: Paleontological Research Volume: 18 Issue: 3 Pages: 176-185
  • DOI: 10.2517/2014pr017
  • NAID: 40020109242
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Morewites, a new Campanian (Late Cretaceous) heteromorph ammonoid genus from Hokkaido (2014)
  • Author(s): Yasunari Shigeta
  • Journal Title: Paleontological Research Volume: 18 Issue: 1 Pages: 1-5
  • DOI: 10.2517/2014pr001
  • Peer Reviewed
• [Presentation] 極東ロシアの中生代アンモナイト研究 (2014)
  • Author(s): 重田康成
  • Organizer: 日本古生物学会
  • Place of Presentation: 九州大学（福岡市東区）
  • Year and Date: 2014-06-27 – 2014-06-29
• [Presentation] 北海道から新たに見つかった上部白亜系カンパニアン階大型化石群
  • Author(s): 重田康成, 伊豆倉正隆, 西村智弘
  • Organizer: 日本古生物学会
  • Place of Presentation: 熊本大学（熊本市黒髪）