Extinct squid relative entombed in amber for 100 million years

The latest discovery in a cache of ancient Burmese amber has revealed something completely unexpected: an extinct squidlike organism called an ammonite, which swam Earth’s seas while dinosaurs dominated the land 100 million years ago. This is the first ammonite and one of the very first marine organisms ever found in amber; because the gemstone is fossilized tree resin, it traps mostly land organisms.

The specimen (above) came to light when a collector in Shanghai, China, bought it for about $750 from a dealer who claimed it was a land snail. Under the x-rays of a computerized tomography scanner, though, the shell revealed the intricate internal chambers characteristic of ammonites.

The ammonite’s precise type confirms the Burmese amber is from the Cretaceous period, as previous dating studies have argued. But the 3-centimeter-long piece of ancient resin is a veritable surf and turf of land and sea creatures, also preserving at least 40 other animals—mites, spiders, millipedes, cockroaches, beetles, flies, wasps, and marine gastropods, the researchers report today in the Proceedings of the National Academy of Sciences .

To explain this unique amber piece, researchers have conjured up three scenarios. Perhaps resin dripped down from a forest next to a beach, catching first land critters and then seashells. Or a tsunami flooded low-lying trees, washing sea creatures into resin pools. Or, possibly, storm winds simply blew seashells into the forest. Regardless, scientists say, it’s a welcome surprise.