• Ottoia is an extinct worm that burrowed in the mud on the seafloor and preyed on other small animals such as worms and trilobites.

• It grew to about 15 cm (6 inches) in length.

• Its mouth was lined with teeth, and could be retracted into the body.

• A collar of spines gave it some protection.

• It has been found in the Burgess Shale of Canada, and in Utah and Nevada of the United States.

Onychodictyon

Nematomorpha, Maotianshania