''Nereis vexillosa'' (common name: mussel worm) belongs to the phylum Annelida, a group known as the segmented worms. It is generally iridescent green and can reach 30 cm in length. It can be distinguished by the size of the upper ligules on the

notopodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed ...

of the posterior region of the body. The upper ligules are much larger than the lower ligules. It is also without a collar-like structure around the

peristomium The peristomium is the first true body segment in an annelid worm's body in the anterior end. It is directly behind the prostomium and contains the mouth, tentacular cirri, and sometimes feeding palps, which may instead occur on the prostomium. If ...

Habitat

Sand or rocks in intertidal and shallow marine waters.

Range

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

from eastern Siberia to western North America as far south as Santa Barbara, California. Also found in Southern Africa.

Behavior

''Nereis vexillosa'' is often found in burrows in the sand or in association with mussels and barnacles. Although it has an eversible

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...

that it uses for prey capture, ''N. vexillosa'' also feeds on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

which it attaches to the opening of its burrow. The algae also serve to regulate temperature, moisture and salinity during low tide.WOODIN, S.A. 1977. Algal “gardening” behavior by nereid polychaetes: Effects on soft-bottom community structure. Marine Biology, 44:39-42.

Reproduction

At sexual maturity, ''N. vexillosa’s'' body is transformed into a heteronereid or epitoke. This body form is full of gametes and its sole purpose is reproduction. Epitokous worms leave their burrows and enter the water column in spawning swarms. This spawning activity marks the end of the organism's life cycle.

Importance

''Nereis vexillosa'' is an important food item for foraging birds in the intertidal zone.WOOTTON , J. T. 1997. Estimates and tests of per capita interaction strength: Diet, abundance, and impact of intertidally foraging birds. Ecological Monographs, 67:45-64. The habit of algal attachment to its burrow facilitates the colonization of the alga.

References

{{Taxonbar, from=Q2384850 Phyllodocida Animals described in 1851