The Invertebrate: The Super-Predator - Anomalocaris of the Cambrian Era

I really love to study about the life in the ocean. That is the reason that I double majored in marine biology and zoology. Life is so exotic and alien in the depths and it fascinates me in the evolution of species from the bottom dwellers to the splash zone. These organisms are part of an ecosystem that remains a favorite of mine to research. Every once in a while, I stumble upon interesting creatures that I like to gain a better understanding of, so I scour the internet and libraries looking for information on those animals. One such animal that I recently undercovered an interest on is called Anomalocaris, or the abnormal shrimp that is related to the arthrods. It is an extinct genus of anomalocaridid. The first fossils were found in both the Ogygopsis Shale and in the famed Burgess Shale.Can you imagine coming up on one of these creatures while diving? Take a look at the size of these "monsters" in comparison to a human. I would be so frightened to have one of these approach me.


The size of the Anomalocaris in comparison to a human

What are Anomalocaris?

These animals were first discovered 1886. Originally, three sections of the animal was discovered and each section was thought to be a different organism. The arms were assigned to be a crustacean, the mouth a jellyfish and the body that of a sponge.

This predator that ruled the oceans during the Cambrian Era, stalked the seas over 540 million years ago. Early fossils were found in British Columbia, Australia, China, Greenland and the USA (Utah). Many researchers regard this creature as an abnormal shrimp probably the largest animal in the Burgess Shale.

It's length is approximately 60 cm long (some reached 6 feet as discovered in China). It has large complex eyes, circular mouth, an oval-shaped head and in the front it's feeding appendages look like combs. To swim, there were 11 pairs of lobes underneath its body, swimming much like a manta ray and was devoid of any type of walking appendages.

It is believed that the Anomalocaris dined on hard-shelled animals, specifically trilobites, as it was discovered in the trilobite beds of the Ogygopsis Shale. There is very strong evidence that they did eat the trilobites through their fossilized fecal pellets containing trilobite parts that were so large that it was determined that only the Anomalocaris was the only creature that was large enough to eat these animals. The round and cylindrical mouth was located underneath the head and contained many tiny teeth that faced inward like sharks. Like the modern shrimp, food was captured by the feeding appendages curling it up and bringing it to the mouth. As it may seem difficult for this prehistoric shrimp (because of the lack of mineralised tissue and unlikely to penetrate the hard shells), to eat these hard-shelled animals, it has been suggested that the creature grabbed their prey in their jaws and using their appendages rock the animal back and forth rupturing the exoskeleton to gain control of the innards. It this was true, it is noted to suggest that perhaps this gave rise to the trilobite behavioral evolution of rolling up to avoid flexing until snapping. Still the jury is out whether Anomalocaris did consume these hard-shelled animals or perhaps sucked on smaller, soft-bodied organisms.


Artist rendition of what Anomalocaris may have looked like

Whatever the case may be, these predators were one of the largest, if not the largest, predator in the sea during the Cambrian Era. They along with the anomalocarid family became extinct after the Mid-Cambrian Period due to the possibility of climatic changes or the emergence of more super predators. They are an interesting animal to read about.