Appearance
This large worm can reach 80 millimetres millimetres in length and 10–12 millimetres in width. It is buff in colour with purple specks. It lives in a tough, leathery tube covered with fine mud. Projecting from this is a branchial crown of branched tentacles, the radioles, which form a plume. The tentacles are striped in dark and pale brown bands and bear neither stylodes nor eye spots. There are two long, slender palps and a four-lobed collar.
Distribution
The native range of ''S. spectabilis'' is the Indian Ocean and the Red Sea, but it is now also found on the coasts of Africa and Mozambique and the Gulf of Mexico. In 2002 it was reported on pilings, floating docks and harbour walls in Hawaii.
Behavior
''S. spectabilis'' is a filter feeder. Cilia on the tentacles cause currents in the water and organic particles are caught as they float past. They are channelled along mucus-filled grooves to the mouth. Larger non-food particles are used for building the tube. The tentacles are also used as gills for gas exchange.This worm can reproduce asexually by fragmentation, and can regenerate body parts after being damaged. Reproduction can also be by sexual means. Most worms are either male or female and the gametes mature in the coelom before being released into the water column. Some specimens, particularly larger ones, have both male and female gametes and a study concluded that this was consistent with sequential hermaphroditism. Fertilization is external, and after a short time in the plankton, the trochophore larvae settle out and grow into adult worms.
Habitat
''S. spectabilis'' is found in holes and cracks and among algae on reefs and rocky shores. It is sometimes found growing in crevices in the coral ''Pocillopora meandrina'', under boulders in still water, in holes in lava, in tidal pools and in channels exposed to heavy surf.References:
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