Anomalocaris ("abnormal shrimp") is an extinct genus of anomalocaridid, a family of animals thought to be closely related to ancestral arthropods. 

Will discovers in Deeper the existence of Anomalocaris canadensis, one of the species of Anomalocaris. This species lived in Topsoil during the Cambrian era, reaching 3 meters in length and more than 70kg. They've been extinct for more than 500 millions years. However, they managed to survive somehow in an underground sea located in the Deeps.

Lifestyle Edit

According to the book Anomalocaris are nocturnal, what earned them the title of 'Night crab'. They are carnivorous and predatory. They keep close to the shore when they're not in the water.

Anatomy Edit


Anomalocaris is thought to have been a predator. It propelled itself through the water by undulating the flexible lobes on the sides of its body. Anomalocaris had a large head, a single pair of large, compound eyes on stalks comprising approximately 16,000 lenses, and an unusual disk-like mouth. The mouth was composed of 32 overlapping plates and a series of serrated prongs in the center. The mouth could constrict to crush prey, but never completely close, and the tooth-like prongs continued down the walls of the gullet. Two large 'arms' (up to 18 centimeters in length when extended) with barb-like spikes were in front of the mouth. The tail was large and fan-shaped, and along with undulations of the lobes, was probably used to propel the creature through Cambrian waters. For the time in which it lived, Anomalocaris was gigantic.

Appearance in Deeper Edit

"You need to get some hot food in you," said Elliott, lifting her foot from the night crab as she unleashed her knife.  The appendages under its head were flexing like animated TV antennae. For a split second of silence, Will took in the creature, then cried out:

"Anomalocaris canadensis!"  He became wildly excited, jumping up and down and waving his arms. Elliott flipped over the night crab and positioned her knife in the join between segments on its flat belly.

"Hey!" Will screeched.  "No!"  He stuck out a hand to stop Elliott from killing it, but she was too quick.  She pushed in the knife and the appendages on its head immediately went limp, ceasing their endless waving.

"No!" he shouted again.  "How could you do that?  It's an Anomalocaris! "  He took a step toward her, his hand outstretched. "It's a fossil... I mean... it's extinct... I mean I've seen a fossil of it...It's EXTINCT!" he yelled, becoming even more agitated as none of the others seemed to understand what he was trying to tell them.

"Really?  Doesn't look too extinct to me," Elliott said, hefting the dead animal up before him.

"Don't you realize how important this is?  You can't kill them!  Leave the rest alone!"  He'd noticed the second sack and wasn't shouting anymore, just yammering, as if he knew he wasn't going to get anywhere with Elliott.

"Will, chill, OK?  The other sack's only got shells in it.  And anyway, Elliott says there's a shed load of these crabs out there," Chester tried to tell him, motioning out to sea.

"But...but... ! It was the biggest predator that swam the seas... the T. Rex of the Cambrian period," Will mumbled forlornly.  "It's been extinct for nearly five hundred and fifty million years [...] None of you has the faintest idea how important the discovery of these animals is," Will said, becoming frustrated all over again by their total lack of interest.  "How can you even think about eating them?"

"If you don't want yours, Will, I'll take it," Cal piped up. 

-Deeper, page 269