Segmented worm, with bristles, possibly zoa eater, ID help please

[andrew__]

http://img.photobucket.com/albums/v37/evilmonkey/Worm_03.jpg

Saw this on a paly polyp today (looked like it was coming out from inside the closed head), missed it the first time but managed to get it as it was returning to the same polyp. The zoas within a small radius around the polyp have been closed for 2-3 days now so I've been watching closely for anything out of the ordinary, hopefully this was it and all is well now. It is about 2 cm long head to tail and a pretty quick mover.

Any and all help appreciated :)

[andrew__]

WetWebMedia gave me my answer:


That is one bizarre but neat looking little creature, isn’t it! What you have is a Polychaete worm (Family: Syllidae) that looks a lot like a species of Myrianida. Its more than unusual appearance is because it’s in a reproductive phase. The parent reproduces asexually by means of budding a succession of attached offspring called stolons (process = stolonization). As you noted, the individuals near the tail appear more mature than those near the main body of the worm. When the juvenile on the end matures sufficiently, it breaks off and takes off! This process continues with the rest of worms on the chain. The really fascinating thing about these worms is that the generations alternate between reproducing sexually and asexually. Although the parent in your case is only capable of reproducing asexually, the offspring (apparently born all male or female) will reproduce sexually. For more information and photo comparison, please see this link: http://www.hawaiianatolls.org/research/CoML/features/polycheates.php

Still not sure if they're a problem for zoanthus species or not but I'll continue to watch for problems.