I'm, glad you joined. Anyone who posts polychaete pictures is my new best friend!
Do you have images of them swimming? I've spoken to 2 colleagues who specialize on fan worms & neither of them have ever heard of Branchiomma leaving the tubes except in response to habitat disturbance or predation. There are no reports of them emerging from the tubes to spawn either. So they are very curious about this behavior.
Small sabellid species are much more mobile than the large ones. They can swim better & it's easier for them to rebuild tubes.
Not all of the species on the list will make it into the Mediterranean. B. spongiarum, for example, is a cold water species described from the Faroe Islands.
Another species newly described for the area is Branchiomma maerli -
Licciano & Giangrande 2008 - the genus Branchiomma in the Mediterranean with the description of B. maerlihttp://scientiamarin...viewArticle/940
Branchiomma bairdi is a newly recognized introduced species in the Mediterranean. It originated in the Caribbeanhttp://www.informawo...ll~jumptype=rss
Color is not always a good way to identify polychaetes. There are some species in which the color pattern is absolutely unique while in others it may be quite variable. A striking example is the christmas tree worm which can be red, white, yellow, blue, green, orange, brown, or even a mix. It always takes specimen examination to be really sure of the species ID.