This week we’re heading right back to the Cambrian Period, over 500 million years ago, when the creatures look a lot like Pokémon, to meet one of the strange inhabitants of the ancient seas… Anomalocaris.
The name means “unusual shrimp,” which is a bit misleading because it wasn’t really a shrimp at all.
When the first fossils were discovered in the late 1800s, scientists back then thought the different body parts belonged to completely separate animals, so the claw-like appendages were described as one creature, the circular mouth as another, and the body as something else entirely.
It took decades before researchers finally realised they all belonged to the same animal.
Anomalocaris was a swimming predator, and quite large for its time, reaching up to about a metre in length. It had flexible flaps running along its sides for propulsion, a pair of grasping appendages at the front to catch prey, and a distinctive circular mouth lined with tooth-like plates, imagine a pineapple ring with teeth!
Most fossils of Anomalocaris come from famous Cambrian fossil sites such as the Burgess Shale in Canada, where exceptionally preserved fossils give us a rare window into early complex life.
What makes Anomalocaris especially fascinating is that it shows just how experimental early animal evolution was. The Cambrian seas were full of strange body plans that look completely unfamiliar compared with most animals alive today.
Fun fact: For many years Anomalocaris was thought to be the top predator of the Cambrian oceans, but its mouth was probably too soft to crush hard shells. It may have specialised in softer prey like worms and early arthropods.
