Organism · Arthropods
Anomalocaris canadensis
Fossil record age bounds · ≈ 510–497 Ma
Inferred life reconstruction
Anomalocaris canadensis
Overview
An unfamiliar hunter swam through the seas around 500 million years ago. Anomalocaris canadensis combined large eyes, spiny frontal appendages, and broad swimming flaps along its sides.[1]
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Key facts
The first discovered body fragments were thought to belong to different animals. A shrimp-like part and a mouth were connected through whole-body fossils. As the pieces came together, a hunter from Cambrian seas emerged.[1]
Time and place
It lived in middle Cambrian seas around 500 million years ago. The Burgess Shale in the Canadian Rockies is a famous window onto this animal and many other unfamiliar marine creatures.[1]
The time range describes source context, not the complete duration of this species.
Size, form and skeleton
Broad swimming flaps line both sides of its flattened, elongated body. Large eyes sit on stalks, and flexible, spiny appendages extend from the front of the head. Some relatively complete specimens are known with body lengths of approximately 25 cm.[1]
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Habitat and reproduction
It is interpreted as having swum by undulating the flaps along its sides. A 2023 study proposed that the frontal appendages were better suited to rapidly catching soft prey in the water than to crushing hard shells.[1][2]
Fossil discovery
ROM collections from the Burgess Shale in the 1990s added several whole-body specimens. Research that began with isolated appendages and mouths expanded to questions about the structure and movement of the entire body.[1]
References
Research questions
Were all injuries on trilobites traces of this animal’s hunting? Earlier interpretations are changing as researchers investigate the strength of its mouth and appendages and the prey it could handle. Its food choices are as intriguing as its reputation as a hunter.[1][2]
Observation
Move your gaze from the large eyes to the frontal appendages, swimming flaps, and tail. Parts that seem unfamiliar to one another join to form a single animal.[1]
Related organisms
Opabinia regalisAnimalsSource time context (not species duration) · ≈ 539–487 MaAnother unusual animal of the Burgess Shale sea
Opabinia is another unfamiliar marine animal known from Canada’s Burgess Shale. Comparing the frontal appendages of Anomalocaris with Opabinia’s long proboscis reveals the diversity of bodies in Cambrian seas.
Wiwaxia corrugataMolluscsSource time context (not species duration) · ≈ 539–487 MaAppendages and sclerites in Cambrian seas
Anomalocaris and Wiwaxia are Cambrian marine animals known from the Burgess Shale in present-day Canada. Compare spiny frontal appendages with body-covering sclerites and spines to explore their different bodies.