Mass Extinction Paved Way for Jawed Fishes' Dominance, Fossil Database Reveals

• A catastrophic ice age extinction 445 million years ago reshaped early marine life, leading to the dominance of jawed vertebrates.
• The Late Ordovician Mass Extinction (LOME) eliminated roughly 85% of marine species due to rapid glaciation, draining shallow seas, and dramatic ocean chemistry shifts.
• Researchers from the Okinawa Institute of Science and Technology, led by Professor Lauren Sallan, published findings in Science Advances, linking this disaster to vertebrate evolutionary success.
• Jawed fishes rose to prominence by surviving in isolated marine refugia, such as South China, where they diversified and adapted.
• The study suggests extinctions act as ecosystem resets, allowing new species to fill vacant ecological niches and leading to recurring diversity cycles.

Why It Matters: A ancient mass extinction event cleared the path for jawed vertebrates to dominate marine ecosystems.