Sabellid "parasite" on abalone (fwd)

Kirk Fitzhugh fitzhugh at mizar.usc.edu
Tue Apr 9 12:24:30 EST 1996


Worm Workers:

The sabellid Carrie Culver referred to is a new genus and species, which is
being described by Greg Rouse (University of Sydney) and myself. Carrie has
been concentrating on possible erradication measures under aquaculture
conditions, as well as conducting some very nice experiments to determine
aspects of the species' population dynamics.

The species was introduced from South Africa, apparently via the abalone
Haliotis midae. At this point, the worm has been found in aquaculture
facilities along Southern California, but there is no evidence that I'm
aware of that it has become established outside of these conditions. I will
be going to South Africa later this year to collect specimens, and determine
the extent of occurrence on other mollusc taxa.

Systematically, the worm is a fairly apomorphic member of the Sabellinae,
and appears to be a sister group to Amphiglena. It has thoracic and
abdominal uncini unlike those seen in any other sabellid. For instance,
uncini on setigers 2-6 are acicular, whereas on setigers 7-8 they are
avicular, with a dentition more similar to that seen in serpulid uncini.
Overall, specimens resemble Caobangia in that the overall body shape is
sac-like. Adults are about 3 mm long, with only two pairs of radioles, and 8
and 3 thoracic and abdominal setigers, respectively. The species is a
simultaneous hermaphrodite and broods lecithotrophic larvae. Unlike other
brooding sabellids, early (nonfeeding) juveniles are released prior to the
development of the branchial crown, which facilitates the unique settling
behavior the juvenile exhibits, consequently being covered over by shell
material by the host abalone. For native abalone under culture conditions,
high worm infestations cause the abalone to produce abnormal shells and
reduced growth. Burrows can be very numerous, likely compromising shell
integrity. It will be interesting to see if the worm becomes established in
California waters, and the impact it will have on other native gastropods.

Sincerely,

Kirk Fitzhugh


---------------------------------------------
Kirk Fitzhugh
Associate Curator of Polychaetes
Research & Collections Branch
Los Angeles County Museum of Natural History
900 Exposition Blvd
Los Angeles CA 90007

Phone:  (213) 744-3233
FAX:    (213) 746-2999
e-mail: fitzhugh at bcf.usc.edu
---------------------------------------------




More information about the Annelida mailing list