Anomalocaris
| Dinocarida
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| Scientific classification
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| Subphyla and Classes
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*Anomalocaridae
- Anomalocarids,extinct
Genus Anomalocaris
Genus Laggania
Genus Parapeytoia
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*Opabinidae - Extinct
Genus Opabinia
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*Unclassified anomalocarid-like specimens
Genus Kerygmachela
Genus Pambdelurion
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Anomalocarids are a group of very early marine animals found in Cambrian deposits in China, North America, and Australia. Anomalocarids were the largest Cambrian animals (up to 60 cm in length), and most of them probably have been active carnivores (although recently Laggania is thought to have been a plankton-eating animal).
They are thought to belong to a primitive arthropods subphylum or to an extinct phylum (Dinocarida) closely related to the arthropods. There are clues that anomalocarid-like genera like Kerygmachela could have been related to the ancestors of all Arthropoda.
Anomalocarids were flat, free swimming, segmented animals with two shrimp-like appendages forward of the mouth. Their mouth is a peculiar structure, somehow resembling a pineapple slice with multiple layers of hard sharp teeth in the central hole. Originally, the jointed arms in front of the mouth were classified as arthropods, the mouth was thought to be a fossilized jellyfish, and the body was not associated with either. Since the pieces were assembled in the 1980s, a number of genera and species have been identified differing in the details of the grasping appendages, whether a tail is present, mouth location, and other features.
The only plausible close relative of the Anamalocarids is another enigmatic early form known as Opabinia.
The Anamalocarids thrived in the Early and Mid Cambrian and then apparently died out.
