Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum No. 2

The fossil fish specimen of the genus Zacco (Cyprinidae), which was collected in 1788 and is now preserved in the Seison-kaku Museum, Kanazawa City, is reviewed again and added some details.

The specimen seems to be deposited in a considerably good natural condition. According to the record written directly on the matrix of the specimen, the scales were once printed clearly. Unfortunately however, the specimen had been weathered before kept safely, yet the remnants of the pharyngeal teeth and the gill organs are still recognizable in the present.

Comparisons of the present specimen with recent species of the same genus (Zacco temminckii & Z. Platypus from Japan, and Z. pachycephafus and Z. (Candidia) barbatus from Formosa) made clear the specific peculiarity of the present fossil specimen.

As for the comparisons with the other forms of the genus, the authors depended exclusively on literatures, so the obtained results were not sufficient. Yet, they could made clear the difference of the present specimen from the three continental forms (Z. macrolepis, Z. asperus and Z. macrophthalmus). But little difference was found between the fourth form, Z. chengtui, so far as the referable non-osteological peculiarity of this Sechwan form has been concerned.

This is the first discovery of the fossil specimen of the genus Zacco, collected presumably from the Early Miocene bed of Japan. With due regards of the preserved state of the present specimen, the future discovery of the same species should make clearthe history of the genus Zacco in the Miocene.