1999 Fiscal Year Final Research Report Summary

CELLULAR STRUCTURE OF PERMINERALIZED BENNETTITALEAN PETIOLE AND STEM NEWLY FOUND

Research Project

Project/Area Number	10640457
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Stratigraphy/Paleontology
Research Institution	INSTITUTE OF NATURAL HISTORY
Principal Investigator	OHANA Tamiko INSTITUTE OF NATURAL HISTORY, INVESTIGATOR, その他の部局, 研究員 (60231205)
Project Period (FY)	1998 – 1999
Keywords	Bennetticarpus / Bennettitales / Hokkaido (Japan) / Late Cretaceous / Upper Yezo Group / 球果目
Research Abstract	Recently many plant-taxa have been described from the marine Upper Yezo Group (Coniacian-Santonian). These plant fossils are preserved as permineralized debris in calcareous nodules together with various marine animals. A single bennettitalean specimen was collected from the Upper Yezo Group. It consists of a receptacle, with numerous fertile (seminiferous) and sterile (interseminal) scales. Although the specimen is fragmented, its anatomical features are well preserved. This study provides a description of a new reproductive organ belonging to Bennettitales. As its affinity to Williamsoniaceae or Cycadeoidaceae and their allies is uncertain, we provisionally place our specimen in the form-genus Bennetticarpus and describe B. yezoites sp. nov. Comparison of Bennetticarpus yezoites with known bennettitalean taxa in other regions is given briefly. The present specimen is in association with various conifers, mainly with Taxodiaceae.