Abstract
Anatomically well preserved fertile and vegetative remains of Glyptostrobus rubenosawaensis sp. nov. (Coniferae-Taxodiaceae) have been recovered from silicified lacustrine deposits of the late Middle Miocene Shimokawa Group near Shimokawa Town, Kamikawa district, Central Hokkaido. Vegetative remains include shoots bearing polymorphic leaves. Fertile remains include seed and pollen cones. The fossil remains closely resemble living Glyptostrobus pensilis (D. Don) K. Koch in gross morphology, but differ in possessing larger cones and a prominent abaxial projection of the bract. Previous reports of fossil Glyptostrobus were limited to compression floras. This report is the first to use permineralized remains to reconstruct fossil Glyptostrobus and document the internal anatomical features of the genus to allow meaningful comparison with the living representative, G. pensilis. Abundant remains of Glyptostrobus indicate wetland as the paleoecological setting, based on the cooccurrence of wetland taxa such as Decodon (Lythraceae), Osmunda and Alnus, and mountainous taxa such as Picea and Tsuga, and using permineralized plant fossils. We can reconstruct an ecological setting in a lake.
