Monday, November 21, 2011

Anomalocaris (Part 2).

I've written about this animal before, but there is more information that I would like to talk about.

Anomalocaris was a very widely distributed Cambrian animal. Their remains have been found in at least China, Australia, Nevada, Pennsylvania, California, Georgia, Utah, Canada, and Greenland. Adults were normally about three feet long, but some could have grown up to six feet. Fossils of Anomalocaris canadensis show that it had a skinny head and long eye stalks, so it could have been able to turn its head and swivel its eyes while it was hunting for prey.

Some scientists believe that Anomalocaris ate trilobites. This evidence comes from Anomalocaris briggsi coprolites found in Australia, which contain pieces of trilobite exoskeletons, as well as trilobites with bite marks in them, which are found in many places. Some scientists don't believe that Anomalocaris normally ate trilobites because its mouth parts may not have been hard enough to penetrate trilobite exoskeletons. Anomalocaris mouth part fossils do not show any signs of being worn down by trilobite exoskeletons. But to some scientists this just points to the spines on the mouth parts being pliable but hard. So it's possible that Anomalocaris did still normally eat trilobites.

Anomalocaris fossils are most commonly found as disarticulated pieces, but well-preserved juveniles and some well-preserved adults are known.

Although A. canadensis had its claws curled up under its head. A. saron had its claws stretched out sideways in front of its face so they would have acted like scissors, where the spikes on one claw faced the spikes on the other claw. But there are other differences between the two species. A. saron had legs and cerci, while A. canadensis did not. But they did share the same basic structure. Some scientists believe Anomalocaris pennsylvanica was just a non-Canadian A. canadensis, but they might be different species.


1 comment:

  1. Hi Art,
    This is Conrad again. Thanks for the tip about the Petrolacosaurus. That was the arthropod I was thinking of. I live in Michigan. Is there any chance that you live close to me so that we can meet and watch walking with monsters together sometime?