In a groundbreaking discovery, the oldest undisputed streptophyte algae fossils have been found in marine carbonate sediments in Northwest China. These fossils, dating back to the early and middle Katian stage (~453-449 Ma), are reshaping our understanding of plant evolution. The well-preserved specimens, named Tarimochara miraclensis, represent a marine Charophyceae species, bridging a significant gap in the fossil record and pushing back the known existence of streptophyte algae.
Researchers have identified calcified thalli and probable calcified utricles, showcasing distinct nodes and internodes along the main axis. The morphology of Tarimochara closely resembles that of present-day Charophyceae, suggesting a highly conservative evolutionary path. This discovery confirms that streptophyte algae thrived in fully marine environments during the Ordovician period.
This find, detailed in a Nature Plants article published in May 2025, supports the theory that land plants evolved from higher-branching streptophyte algae. The exceptional preservation and widespread distribution of T. miraclensis provide critical insights into the origins of land plants, marking a major step forward in understanding the early evolution of plant life. This discovery was made by a team led by Professor Liu Lijing from Northwest University, China.