1. Department of Geology and Paleontology, National Museum of Nature and Science, 1-4 Amakubo, Tsukuba-shi, Ibaraki 3050005, Japan (e-mail: )
2. College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa-shi, Ishikawa 9201192, Japan
3. Faculty of International Resource Sciences, Akita University, 1-1 Tegatagakuen-machi, Akita-shi, Akita 0108502, Japan
4. Institute of Geology and Geoinformation, National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba-shi, Ibaraki 3058567, Japan
5. Nakagawa Museum of Natural History, 28-9 Yasukawa, Nakagawa-cho, Nakagawa-gun, Hokkaido 0982626, Japan