Preservation of luminescent organs in the Miocene deep-sea lanternfish fossils

• Project/Area Number: 18K03827
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17050:Biogeosciences-related
• Research Institution: Kyushu University
• Principal Investigator: MAEDA Haruyoshi 九州大学, 総合研究博物館, 教授 (10181588)
• Co-Investigator(Kenkyū-buntansha): 田中 源吾 金沢大学, GS教育系, 助教 (50437191)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: タフォノミー / 師崎層群 / 深海魚化石 / 発光器 / メラノソーム / ハダカイワシ類 / ソトオリイワシ科 / 軟体部保存 / 腐敗 / 古生物学 / 化石鉱脈

Outline of Final Research Achievements

The preservation of luminescent organs of lantern fish fossils from the Miocene Morozaki Formation in Aichi Prefecture, Japan, was carefully examined from the viewpoint of taphonomy. As a result of introducing "infrared-" and "ultraviolet photography", the traces of soft parts and the shape of luminescent organs, which could not be identified by conventional visible light observation, were clearly captured. SEM, TEM, and TOF-SIMS analyses revealed that the shape and original arrangement of the focusing lens, reflector (tapetum), and pigment particles were preserved in the fossils. In addition, melanosomes are preserved in some of the tapetums. This is the first example of a light-absorbing tissue containing the pigment melanin, which means that the original organic material of the luminescent organ may have been preserved.

Academic Significance and Societal Importance of the Research Achievements

従来，海外に比べて日本は化石の保存が悪いといわれ，その分，化石鉱脈と呼ばれる軟体部保存を示す例外的な化石の研究において西欧諸国の後塵を拝していた．今回，約1,600万年前の師崎層群産の深海魚化石が発光器の痕跡を保っていることを明らかにし，世界的に著名な化石鉱脈に匹敵するレベルの化石鉱脈が日本にも存在することを示した．これは，変動帯に位置する日本固有の化石鉱脈の研究が有望であることを示したものといえる．

Research Products

• [Journal Article] 下部ジュラ系ヒルドセラス科アンモノイド化石の岩相による保存状態の違い (2021)
  • Author(s): 前田晴良・大山 望・松井 悠・河野秀晴・伊藤泰弘
  • Journal Title: 豊田ホタルの里ミュージアム研究報告 Volume: 13
  • Open Access
• [Journal Article] Madygella Humioi sp. nov. from the Upper Triassic Mine Group, Southwest Japan: The Oldest Record of a Sawfly (Hymenoptera: Symphyta) in East Asia (2020)
  • Author(s): Oyama Nozomu、Maeda Haruyoshi
  • Journal Title: Paleontological Research Volume: 24 Issue: 1 Pages: 64-71
  • DOI: 10.2517/2019pr005
  • NAID: 210000157835
  • Peer Reviewed
• [Journal Article] Mesozoic insect fossils of Japan: significance of the Upper Triassic insect fauna of the Mine Group, Yamaguchi Pref. (2020)
  • Author(s): Oyama Nozomu, Yukawa Koichi, Maeda Haruyoshi
  • Journal Title: Bulletin o the Mine City Museum, Yamaguchi Prefecture, Japan Volume: 33 Pages: 1-13
  • NAID: 120006998858
  • Peer Reviewed
• [Journal Article] Stratigraphy and fossil assemblages of the Triassic Mine Group and Jurassic Toyora Group in western Yamaguchi Prefecture (2019)
  • Author(s): Maeda Haruyoshi、Oyama Nozomu
  • Journal Title: The Journal of the Geological Society of Japan Volume: 125 Issue: 8 Pages: 585-594
  • DOI: 10.5575/geosoc.2019.0020
  • NAID: 130007776160
  • ISSN: 0016-7630, 1349-9963
  • Year and Date: 2019-08-15
  • Peer Reviewed
• [Journal Article] First discovery of Eocene coastal-estuarine ostracods from Japan, with the geological history of the migration of estuarine genera in the Far East (2018)
  • Author(s): Tanaka, G., Hemmi, Y., Komatsu, T., Hirose, K., Ugai, H., Kawano, S., and Maeda, H.
  • Journal Title: Geological Magazine Volume: 155 Issue: 8 Pages: 1742-1760
  • DOI: 10.1017/s0016756817000693
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Early Permian (Cisuralian) ostracods from Japan: characteristic ostracod assemblage from a seamount of the Panthalassic Ocean (2018)
  • Author(s): Tanaka, G., Miyake, Y., Ono, T., Yuan, A.H., Ichida, M., Maeda, H., and Crasquin, S.
  • Journal Title: Zootaxa Volume: 4515
  • Peer Reviewed / Int'l Joint Research
• [Presentation] ソトオリイワシ科深海魚化石の軟体部保存（特に発光器） (2019)
  • Author(s): 前田 晴良
  • Organizer: 日本古生物学会ー夜間小集会
• [Presentation] ソトオリイワシ科深海魚化石の軟体部保存（特に発光器） (2019)
  • Author(s): 前田 晴良
  • Organizer: 日本古生物学会－夜間小集会
• [Book] 新しい地球惑星科学 (2019)
  • Author(s): 小松俊文・前田晴良・田中源吾ほか26名（共著）
  • Total Pages: 287
  • Publisher: 培風館
  • ISBN: 9784563025229