Ashes from a volcanic eruption 300 million years ago helped preserve the ancient forest of the newly characterized ferns of Noeggerathiales. Ashes prevented fossil rotting.
Fossil plants preserved from the fall of volcanic ash in China shed light on the evolutionary process 300 million years ago, which the seed plants ultimately won. They dominate most of the Earth today. A new study of fossils found in Inner Mongolia shows that Noeggerathiales plants were highly developed plants on the line from which the seed species originated. By themselves, Noeggerathiales are a now extinct order of vascular plants. The range of the order’s fossils extends from the Carboniferous to the Triassic. Due to gaps in the fossil record, this group is not fully known and poorly defined, and their taxonomic status and position in the plant kingdom are unclear.
Noeggerathiales were important peat-forming plants that lived from 325 to 251 million years ago. Understanding of their relationship with other plant groups has so far been limited to poorly preserved examples. Fossils found in China have allowed experts to understand that Noeggerathiales are more closely related to seed plants than other groups of ferns.
They are no longer considered an evolutionary dead end. They are now officially recognized as advanced tree ferns, which have developed complex, tapered structures from modified leaves. Despite their complex structure, these tree-like ferns have fallen prey to massive environmental and climatic changes 251 million years ago.
An international research team led by paleontologists from the Nanjing Institute of Geology and Paleontology (China) and the University of Birmingham (UK) published their findings today in Proceedings of the National Academy of Sciences.
“The fate of Noeggerathiales is a vivid reminder of what can happen when even highly advanced life forms are faced with rapid environmental changes,” the scientists emphasize.
The researchers studied Noeggerathiales, preserved in a layer of volcanic ash 66 cm thick.It was formed 298 million years ago, suppressing other plants growing in a nearby swamp. The ashes prevented fossil rotting and preserved an entire forest of specimens in microscopic detail.