Sharks were swimming before trees stood
Shark-like fishes appear in the fossil record before the earliest trees. Teeth and scales of chondrichthyans predate Archaeopteris.
Established2 min read
The first plants tall enough to be called trees show up in the late Devonian, around 385 million years ago. Archaeopteris had wood and a canopy. Shark-like scales and teeth are older than that, back into the early Devonian and, for some remains, the Silurian.
‘Shark’ is a living word laid on a stem. The animals were not great whites. They were cartilage, denticles, and a body plan that still works. Wood was invented later, and then forests changed the climate. The hunters were already in the water.
Caveats
- Which fossil counts as the first shark depends on the cladogram. The order of appearance — chondrichthyan remains, then trees — is the robust part.
Sources
- 1Meyer-Berthaud B., Scheckler S. E., Wendt J.. The Rise of Trees. Nature 398, 1999.