comb jelly

Mnemiopsis leidyi at the Monterey Bay Aquarium, California

FRANS LANTING, MINT IMAGES/SCIENCE PHOTO LIBRARY

Marine animals called comb jellies have nervous systems unlike those of any other known animal. Their neurons are oddly shaped and use chemicals not found in those of other animals.

“These neurons are quite unique,” says Pawel Burkhardt at the University of Bergen in Norway.

The comb jellies’ peculiar neurons may be an adaptation for their lifestyle and the way their bodies work.

They also add to the ongoing debate among evolutionary biologists about how the first animal brains evolved. In particular, there is controversy over …