Predator-prey interactions between marine reptiles and coleoid cephalopods throughout the Mesozoic.

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K17825
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Stratigraphy/Paleontology
• Research Institution: Hokkaido University
• Principal Investigator: Iba Yasuhiro 北海道大学, 理学研究院, 准教授 (80610451)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 頭足類 / 進化史 / 中生代 / 捕食被食

Outline of Final Research Achievements

Modern-type coleoid cephalopod comprises squid, cuttlefish and octopuses. They had an important position in ancient ecosystems, as important prey for marine reptiles as do modern squids now. The evolutionary history of this group is, however, hardly known because of lack of their fossil records. Here we develop a novel tomographic method and reconstruct diversity of modern-type coleoid without collection bias throughout the Late Cretaceous. And also we reveal its predator-prey relationship with marine reptiles throughout the Mesozoic.

Free Research Field

古生物学

Academic Significance and Societal Importance of the Research Achievements

頭足類は，カンブリア紀～現在までの５億年間，世界中の海洋に繁栄し，絶滅と放散を繰り返してきた．現生の海洋における頭足類は，イカ・タコ類に代表され，これらは遊泳生物として魚類に次ぐバイオマスをもつ．現在海洋生態系の頂点に位置するハクジラ類等はイカ類を選択的に捕食しており，彼らの生命は，イカ類の圧倒的なバイオマスに支えられている．本研究では，現生と同様に過去には，海棲爬虫類などの頂点捕食者が，鞘形類（イカ・タコ・コウモリダコ・ベレムナイト類など非外殻性頭足類）に支えられてきたその変遷史を明らかにした．