They aren't very big, averaging about 1.5 inches in length.
Download Christmas Tree Worm Classification
Background. One major difference between christmas tree worms and the closely related sabellida fan worms is that the latter do not have any specialized body structures to plug their tube holes when they withdraw into them. The tops of christmas tree worms look like brightly colored plants.
Spirobranchus Giganteus Wikiwand from upload.wikimedia.org
Both its common and latin names refer to the two chromatically hued spiral structures, the most common feature seen by divers. Googly eyes these technicolor trees aren't plants. Giganteus, like other members of its family, possesses a modified radiole.
The brilliance and beauty of this weird animal sure enliven the dull seafloor.
Bizarre christmas tree worms look out for predators using their gills: Googly eyes these technicolor trees aren't plants. When danger is near, they pull their gills in and hide in tubes below. These guys look like plastic toy christmas trees in a plastic toy forest.
