Review of Japanese Dinosaur Track Localities: Implications for Ichnotaxonomy, Paleogeography and Stratigraphic Correlation

Nine dinosaur ichnospecies from the Lower Jurassic to Upper Cretaceous of Japan, including two that are new, are described herein. The new ichnotaxa are Asianopodus pulvinicalx ichnogen. et ichnosp. nov. and Schizograllator otariensis ichnosp. nov. The Japanese ichnotaxa are allied to Lower Jurassic ichnospecies in South China, North America, Western Europe and South Africa, and Upper Jurassic to Lower Cretaceous ichnospecies from Southeast and East Asia. This suggests they were part of a global ichnofauna before continental drift began in the Middle Jurassic, leading to the development of a more endemic dinosaur fauna in the Cretaceous. At least two assemblages, an ornithopod-gracile-toed theropod-dominated community, in northeastern Asia, and a robust theropod- and sauropod-dominated community in the southern part of the continent, existed in the Cretaceous. This parallels North American dinosaur distribution patterns in the Cretaceous and seems to be a reflection of paleolatitudinal controls.

Keywords:

• Japan
• dinosaur tracks
• stratigraphy
• ichnotaxonomy
• paleogeography
• stratigraphic correlation

ACKNOWLEDGEMENTS

We thank Ikuwo Obata (National Science Museum, Tokyo) and Makoto Ito (Chiba University) for their comments on our work. We are indebted to M.Tanimoto, T. Hamuro and the Shirakawa village Board of Education for their courtesy to let us have the opportunity for this study. The study was financially supported in part by funds from the Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science (Matsukawa, no. 1183303, 1999-2000), and the Grant-in-Aid for University and Society Collaboration of the Japanese Ministry of Education, Science, Sports and Culture (Matsukawa, no. 11791012, 1999–2001).