Trilobite Extinction Linked to Permian-Triassic Boundary

The extinction of the trilobites, a major group of marine arthropods, is strongly associated with one of the most severe extinction events in Earth's history.

Geological Time Boundaries and Extinctions

• The question asks which geological time boundary is linked to the extinction of Trilobites.
• Trilobites were abundant throughout the Paleozoic Era but declined significantly towards its end.
• The Permian-Triassic (P-T) boundary, approximately 252 million years ago, marks the end of the Paleozoic Era and the beginning of the Mesozoic Era.
• This event, often called the "Great Dying", was the most profound mass extinction, wiping out an estimated 96% of marine species and 70% of terrestrial vertebrate species.
• The P-T extinction event caused the final extinction of the trilobites, ending their over 270-million-year reign.
• While other boundaries (Ordovician-Silurian, Triassic-Jurassic, Cretaceous-Palaeogene) were also associated with significant extinctions, the P-T event was the one that definitively ended the trilobite lineage. The Cretaceous-Palaeogene extinction is famously associated with the end of the dinosaurs.

Therefore, the extinction of Trilobites is primarily associated with the Permian-Triassic geological time boundary.