Sea Turtle (Green)

# Evolutionary Timeline of the Green Sea Turtle The green sea turtle (*Chelonia mydas*) belongs to the family Cheloniidae, with roots tracing back to ancient reptiles. Their evolution involved major transitions from terrestrial to fully marine lifestyles, driven by environmental pressures like changing sea levels, climate shifts, and predation. Key milestones include: - **Triassic Period ( ~220 million years ago)**: Emergence of early turtle ancestors like *Proganochelys*, featuring protective shells amid predatory pressures from dinosaurs. - **Jurassic Period ( ~150 million years ago)**: Transition to aquatic habitats, with ancestors like *Plesiochelys* adapting flippers for swimming in expanding oceans. - **Cretaceous Period ( ~100-66 million years ago)**: Rise of true sea turtles in the superfamily Chelonioidea, including giant forms like *Archelon*, influenced by warm, shallow seas and mass extinctions. - **Eocene Epoch ( ~50 million years ago)**: Diversification of modern Cheloniidae family, with adaptations for herbivory in response to abundant seagrass meadows post-K-Pg extinction. - **Miocene to Present ( ~23 million years ago - now)**: Refinement of migratory behaviors and streamlined bodies, shaped by ice ages, ocean currents, and human impacts.