Sardine

# Evolutionary Timeline of Sardines Sardines, belonging to the family Clupeidae, are small pelagic fish with a rich evolutionary history tied to marine environments. Their evolution reflects adaptations to schooling behavior, predation pressures, and oceanic changes. Key milestones include: - **Devonian Period (419–358 million years ago)**: Emergence of early ray-finned fishes (Actinopterygii), ancestors to modern bony fish including sardines, driven by diversification in ancient seas and predation from larger marine predators. - **Triassic Period (252–201 million years ago)**: Rise of Teleostei, the dominant group of bony fishes, with improved jaw structures and fins for better maneuverability amid mass extinctions and changing ocean ecosystems. - **Cretaceous Period (145–66 million years ago)**: Origin of Clupeiformes (herring-like fishes), including early sardine relatives, influenced by abundant plankton blooms and the breakup of supercontinents affecting ocean currents. - **Paleogene Period (66–23 million years ago)**: Diversification of modern clupeids post-dinosaur extinction, with adaptations for filter-feeding on plankton in response to recovering marine food webs. - **Neogene Period (23–2.6 million years ago)**: Evolution of genus Sardina, featuring schooling as a defense against predators in open oceans, shaped by climate fluctuations and glacial cycles.