Devonian age of fish: oceans, reefs and first legs
From 419 to 359 million years ago armored fish ruled seas while fins turned into limbs on land.
Armored giants and coral reefs
The Devonian lasted from 419 to 359 million years ago, about 60 million years. Warm epicontinental seas held vast stromatoporoid reefs stretching hundreds of kilometers across tropical shelves.
Placoderms like Dunkleosteus reached 6 to 8 meters and weighed about 1 tonne. Lobe-finned fish, sharks, ammonoids and giant sea scorpions up to 2 meters shared predator roles in complex food webs.
Fins to legs and final crisis
Around 375 million years ago Tiktaalik carried wrist-like fins and a neck, bridging water and land. By 385 million years ago forests of 8-meter Archaeopteris covered floodplains, while wingless insects spread in leaf litter.
A series of pulses near 372 and 359 million years ago killed about 75 percent of species. Reefs collapsed, placoderms vanished, but lobe-finned survivors gave rise to four-limbed tetrapods in recovering rivers.
- Lasted 60 million years, 419 to 359 million years ago.
- Dunkleosteus reached 8 meters and 1 tonne.
- Tiktaalik lived about 375 million years ago.
- Early forests grew 8 meters tall.
- Extinction killed about 75 percent of species.