Sea Dragons
Big news about ichthyosaurs, which cruised ancient oceans while dinosaurs ruled the land
By Sid Perkins
About 250 million years ago, reptiles stepped up to fill ecological niches left vacant in the wake of one of Earth’s biggest mass extinctions. Just a few million years later, as the earliest dinosaurs stomped about on land, some of their reptilian relatives slipped into the surf and began to exploit the rich ocean ecosystems. Before long, these ichthyosaurs—Greek for fish lizards—became major players in the marine environment, taking on the roles that seals, dolphins, and whales occupy today.
Ichthyosaurs swam through prehistoric seas for more than 150 million years, almost as long as their dinosaur cousins ruled the land. While some of the creatures retained the lizardlike proportions of their ancestors, others were as sleek as porpoises and probably had a lifestyle similar to that of those modern mammals. Analyses of ichthyosaur fossils are shedding new light not only on their body structure, but also on what they ate and how they may have homed in on their prey. Fossils still being teased from the rock strongly hint that the largest predator ever on our planet may well have been an ocean-dwelling ichthyosaur.