Phascolion strombus strombus (Montagu, 1804)
A cosmopolitan species often found in mollusk shells and polychaete tubes.
Size
- Common trunk length: 5-15 mm
- Maximum trunk length: 30-40 mm
Color & Characteristics
- Grey, brown, yellowish, reddish
- Two retractors: ventral retractor much thinner then dorsal
- Holdfast papillae V-shaped with dark hardened border
- Sharp, clawlike hooks
- 10-30 well-developed tentacles present on the introvert
- An aggregation of large papillae around the anterior end of the trunk
- Trunk length 30-40 mm (usually 5-20 mm)
- Some worms lack hooks, probably due to predation and regeneration of introvert
- There is an extreme plasticity of form of this very widespread and common species
Habitat & Distribution
- Very common and eurytopic in the North Atlantic and Arctic oceans
- Known from depths of 1-4030 m
- Inhabits sand, mud, silt; it avoids soft clay due to clogging of the shelter apertures
- Uses empty mollusc shells, polychaete tubes and foraminiferan tests as a shelter - density tends to be limited by a number of available shells and tubes
- In Svalbard found at depths from 79-390 m
Feeding
- Semi-mobile deposit feeder, collecting sediments with tentacles
Life cycle
- Freely spawn gametes into the water
- A short-term lecithotrophic trochophore larva
- Usually, after settlement they do not disperse
Page Author: Monika Kedra
Created: August 11, 2010