[Please direct replies to the enquirer - Moderator]
I am a lightly-trained invert zoology buff, and a marine aquarium hobbyist.
I have an annelid that I am trying to evaluate as marginally economically
important, because it seems to appear with frequency in the "reef aquarium"
trade.
One of the marine substrates reef aquarists may collect "live rock", which
is usually synonymous with wild-collected dead coral rubble (although many
live specimens are available too) from a reef.
As a substrate in an aquarium, live rock is thought to provide capacity for
anaerobic digestion, imporatnt in maintaining low nutrient load in the reef
tank. Live rock has the extended benefits of usually introducing, to the
captive reef, a small ecosystem replete with a host of marine invertebrates
like annelids, amphipoda, and other zoo- and phytoplankton.
I have singled out a marine polychaete whose presence in my tank possibly
goes back to the installation of live rock from Micronesia. This organism
is observed widely in the hobby, if aquarium newsgroup posts are any
indication, and is often identified, without benefit of analysis, as a
bristleworm, which is in turn often assumed to be either a predator on
bivalvia and other prized specimens, or a fire worm, which would be a
genuine cause for concern (it gives painful stings that may require
hospitalization) if it were a correct identification but is usually not.
My interest in this annelid is the former: I want to know if it is a
predator. It flourishes in some tanks, occupying tiny holes in the coral
substrate, and stretching out after dark, even going peripatetic in search
of food. Many times I have found them in close association with specimens
that are then observed to be moribund. Whether this is a result of
polychaete-induced stress (either feeding on the stressed organism, or
simply generating locally high levels of waste), or whether the polychaetes
are being terribly good at cleaning up dead/dying specimens isn't clear to
me. The aquarium trade loudly insists that the worms are no predators! At
any rate, the technology doesn't exist to rid a reef tank of the denizens,
so onehopes they are essentially benign, only facultative carnivores if at all.
On my web site I have posted a picture of a specimen which is inadequate
but suggestive. Organism is ~ 2" long . I worked out some of the most
diagnostic systematics, hope I've done something useful:
60 segments, first 10 anterior are pink incolor, gut begins where segments
become dark in appearance in photo)
Dorsal paraposium w/gills, many fine setae and one large seta.
Ventral lateral parapodia w/many fine setae and one large seta.
Prostomium rounded, slight indentation in center
First 4 or 5 anterior segments have a longitudinal raised area (a ridge).
4 eyes (1 pr large eyes, one pr small eyes), arrayed along anterior lateral
margins of the raised area.
(darn, I did a second study that I can't lay my hands on now). I'll try
and answer questions based on the study (if I find it) or a live a specimen.
The most telling attribute, vis a vis the question of whether or not they
prey on valuable tank specimens, seems most likely to be their feeding
apparati. This worm has an evertable pharynx, but I cannot, with my Tasco
2X and very sharp dissecting tools, find any sign of hooks, teeth, or
grabbers inside the pharynx. The inner surface of the pharynx is striated,
evident when everted and cut longitudinally.
So, hopefully the picture ( http://www.edword.com/annelid/Image073.jpg )
will trigger some recognition! I await your insights, thou most collegial
scientists and classifiers. Thank you very much in advance, and thanks again.
--Ned
<nbedinger at uswest.net>
------------------------------------------------------------------------------
Ned Bedinger | Edword Technical Communications Co.
Seattle, WA | Life Cycle Documentation, User Guides
___________________________________________________
If this were merely my opinion, I'd probably keep it to myself.
My employer is not responsible for my expressions.
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