Genus: Anomalocaris

Anomalocaris is an extinct order of marine animals which are thought to be closely related to ancestral arthropods. Initially, it was misidentified as parts of its body did not completely fossilize. But as more specimens were discovered, paleontologists were able to recreate what anomalocaris may have looked like in real life.

Also Refer: Aquatic Ecosystem


The name “Anomalocaris” is derived from the Greek word “anomoios, which translates to “unlike” and the Latin word “caris”, which translates to “shrimp/ crab”. Hence, Anomalocaris means “unlike other shrimp”.

Characteristics / Morphology of Anomalocaris:

Anomalocaris roughly resembles a giant prawn with long, spiked appendages near its head. Other characteristic features include:

  • Bilateral symmetry
  • The animal was dorsoventrally flattened
  • It also had a non-mineralized exoskeleton
  • Its body is divided into segments, with a prominent tail fan that had three pair of upward-extended fins
  • Also on its body was at least 11 swimming flaps which was positioned laterally
  • Its head is very distinct, with large prominent eyes on stalks
  • Moreover, its frontal area had two long appendages, which had 14 segments each. Its appendages were also lined with sharp spikes that projected from its ventral surface.
  • Based on fossil fragments, paleontologists suggest that these animals could reach upto 100 cm in length.


Anomalocaris was a carnivore and lived during the Cambrian Period. Using its flexible flaps on the sides of the body, anomalocaris may have actively hunted for prey. Scientists speculate that it fed on animals such as the trilobites as well as soft-bodied animals that resembled priapulids. However, some evidence suggests that certain species of Anomalocaris may have been filter feeders.

Explore More: Cambrian Explosion

Were Anomalocaris Apex Predators?

For the time period in which it lived, it was one of the biggest animals ever, growing up to 3.3 feet long. The location of its eyes, as well as its mid-gut glands strongly suggests that anomalocaris was a predator. Another supporting evidence of its predatory lifestyle is its frontal appendages, which it may have used like a claw to grasp prey. Other scientists have speculated that anomalocaris may have grabbed one end of their prey in their jaws and then quickly rocked it back and forth. This action produced stresses in the cuticle of arthropods, causing its exoskeleton to rupture and allowing access to its innards. This behavior was speculated to be the evolutionary pressure that caused trilobites to roll up, to avoid being flexed.

Explore More:  Evolution

Frequently Asked Questions on Anomalocaris


What was Anomalocaris?

Anomalocaris is an extinct order of marine-animals which are thought to be closely related to ancestral arthropods. It lived during the Cambrian Period and superficially resembles a giant prawn/ shrimp.


Is Anomalocaris extinct now?

Yes, Anomalocaris became extinct around 510 million years ago.


Did Anomalocaris live on land?

No, Anomalocaris was a marine organism and was widespread during its time period.

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