A research group led by Assistant Professor Legrand Julien of Shizuoka University's Faculty of Science and Dr. Maher Ahmed (Graduate School of Science and Technology) has discovered primitive plants from geological strata dating back 4.1 to 3.9 million years ago (Early Devonian Period of the Paleozoic Era) in Ofunato City, Iwate Prefecture. discovered fossilized spores. This is Japan's oldest plant fossil, dating back more than 1000 million years to previous records.
According to Shizuoka University, the research group extracted spore fossils by grinding rocks collected in the Nakazato Formation, which is distributed in Ofunato City, and observed them with a scanning electron microscope. I found a spore with a Y-shaped mark on it.
A closer look at the spores with the Y-shaped mark revealed that they include the primitive vascular group Rhinia, the Lycodont, and the Trimerophyton, the ancestors of modern ferns and seed plants. I found out that there is.
The Nakazato Formation is a stratum that was deposited in the ocean, and the discovery of index fossil trilobites indicates that it was deposited between 4.1 and 3.9 million years ago. Until now, Japan's oldest plant fossils are of the late Devonian period (3.8 to 3.6 million years ago) found in Iwate and Kumamoto prefectures. This resulted in a far earlier record.
Plants spread onto land by 4.8 million years ago. The ancestors of vascular plants diversified during the early Devonian period (4.2 to 3.9 million years ago), and the ancestors of the plants we see today are all present. This diversification was a major biological event comparable to the Cambrian explosion of animals, but there was no data on plant fossils in Japan.
Paper information:【Paleontological Research】Early land plant spore assemblage from the Devonian Nakazato Formation of the South Kitakami Belt, Northeast Japan
