Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum No. 4

Cretacrous fossil elasmobranchs from Japan (First report)

Research group for Mesozoic fossil shark

Published: 1977/12/25 　 Page: 119–138, pls. 30–34

Fossil elasmobranchs collected from Cretaceous System in Hokkaido and Miyako, Iwate Prefecture of Honshu are studied. Twelve species and one subspecies of nine genera in seven families are recognized in them as shown in Table 1 and described briefly.

Followings are clarified as characteristics of Cretaceous fossil elasmobranchs under examination.

1. They occur from Aptian to Santonian in age.

2. There are many common species with European one.

3. It is assumed that there may be difference in species or subspecies in case of Ptychodus and Cretolamna in accordance with difference on their horizon.

4. Biostratigraphical correlation with other fossils as Ammonoidea and Inoceramus is shown in Table2.

5. Research on Cretaceous fossil elasmobranchs in Japan is an interesting field in biostratigraphy and paleobiogeography.