Filogranella elatensis (Delicate tube worm)

Identification

Tube worms with bright red plumes, gradually turning pale towards the ends. The plumes extend from thin white and clustered calcareous tubes.

Status

Unassessed by the IUCN Red list. Not very common, but spread widely due to ballast water discharge from ships.

Habitat

They can be found in the Red Sea, the Gulf of Aqaba, the Indian Ocean and the Indo-Pacific. They attach to hard substrates such as rocks and boulders, but are also seen in harbors and pier pilings, in overhangs and under coral heads, starting at 5 meters and down to considerable depths, well beyond the dive limit.

Reproduction

Sexual reproduction. Females produce a pheromone attracting and signalling the males to shed sperm which in turn stimulates females to shed eggs, also referred to as swarming. Gametes are spawned through the metanephridia or body wall rupturing (termed as “epitoky”, wherein a pelagic, reproductive individual, “epitoke”, is formed from a benthic, nonreproductive individual, “atoke”). After fertilization, most eggs become planktonic. Life Cycle: Eggs develop into trocophore larva, which later metamorph into juvenile stage (body lengthened), and later develop into adults.

Size

The plume are 2,5cm. in diameter, the tubes can grow much longer.

Prey / Predation

They are filter feeders, sifting out food particles from the water current.

Special features

This species and many other tube worms are very sensitive to light changes. If you approach it too quickly or abruptly, it will retract into its tube.