Ophiodromus pugettensis (Johnson, 1901)
Common name(s): Bat star commensal worm
|Synonyms: Podarke pugettensis|
|Ophiodromus pugettensis, about 2 cm long, from a sponge in Padilla Bay.|
|(Photo by: Dave Cowles, July 2, 2010)|
How to Distinguish from Similar Species: Podarkeopsis bervipalpa has 8 pairs of tentacular cirri. Micropodarke dubia and Kefersteinia cirrata have only 2 prostomial antennae..
Geographical Range: Japan, southern Alaska to Gulf of California (Mexico); Peru.
Depth Range: Intertidal and subtidal
Habitat: Free-living on muddy bottoms or commensal on the ambulacral grooves of seastars such as Patiria miniata. Less common seastar hosts include Luidia foliata, Pteraster tesselatus, and Oreaster occidentalis. It may also be found on moon snail shells occupied by hermit crabs.
Biology/Natural History: This species
is attracted to sea stars by chemoreception. Up to 20 can be found
on a seastar host, and coexist peacefully with each other. They reside
in the ambulacral groove or crawl over the oral surface. They readily
crawl onto another host if it is nearby, or can often be found on the mud
bottom without a host. Freeliving individuals do not seem interested when
presented with a seastar host. The worms eat diatoms, harpactacoid copepods,
and other small benthic invertebrates. They can live in polluted water
low in oxygen but are most common in clean water. This individual
was found by Michael Kutzner when it exited a Mycale
adhaerens sponge from Padilla Bay.
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Lamb and Hanby, 2005
Morris et al., 1980
Ricketts et al., 1985
Hickick, J.F. and D. Davenport, 1957. Further studies in the behavior of commensal polychaetes: Three species of commensal polychaetes, Ophiodromus pugettensis, Arctonoe fragilis, and A. vittata, are attracted by chemicals released by their respective hosts. Biological Bulletin 113: pp 397-406.
Lande, R. and D.J. Reish, 1968. Seasonal occurrence of the commensal polychaetous annelid Ophiodromus pugettensis on the starfish Patiria miniata. Bulletin of the Southern California Academy of Sciences 67: pp 104-111
Schaffer, P.L., 1979. The feeding biology of Podarke pugettensis (Polychaeta: Hesionidae). Biological Bulletin 156: pp 343-355
Pettibone, M.H., 1953. Some scale-bearing polychaetes of Puget Sound and adjacent waters. University of Washington Press, Seattle, WA. 89 pp.
General Notes and Observations: Locations, abundances, unusual behaviors:
A closeup of the head. Note the prominent eyes, the 5 antennae
from the prostomium,
cirri from the first few segments, and the very long dorsal cirri
which extend from the parapodia.
A piece of debris is attached to one of the tentacular
cirri. Photo by Dave Cowles