Idiognathoides corrugatus-Idiognathoides sinuatus assemblage zone is discovered in the lower part of Benxi Formation in southern Shandong and northern Jiangsu and absent in the central part of North China Platform.

• 在鲁南、苏北本溪组下部发现了Idiognathoides corrugatus-Idiognathoides sinuatus组合带,该组合带在地台中部缺失。