Modes of ammonoid occurrence and preservation in siderite concretion

点击翻译按钮获取中文摘要

Well preserved census assemblages of Sphenoceramus naumanni were newly discovered from several unfossiliferous horizons including oxygen-depleted environments, in which siderite nodules were formed. Still retaining their life-habit, they seemed to be buried and preserved in situ. The paradoxical result that the fossil individuals lived in unsuitable condition retained much original ecological information would be a tip to reconstruct paleoecology of inoceramid bivalves in further research.