Polydora hoplura Claparède, 1868

Status
Pest, Invasive

Description
Robust, up to 40mm for 180 segments and 2mm wide at chaetiger 5. Dark pigmentation along prostomium and on peristomium, sometimes on pygidium. Palps often with black bars. Pigmentation may be absent. Prostomium bilobed, weakly incised anteriorly or rounded, caruncle to end chaetiger 3. Up to 2 pairs of eyes.
No notochaetae on chaetiger 1.Modified spines of chaetiger 5 simple hooks with flange on concave edge. Strong hooks on posterior chaetigers.
Branchiae begin on chaetiger 7, long & filiform, usually end before posterior notochaetal hooks begin.
Pygidium saucer-shaped.

Distribution
South Africa: Northern Cape, Western Cape and Eastern Cape provinces
English Channel, Atlantic coast of Europe, Australia, New Zealand and the Mediterranean Sea (Type locality Bay of Naples).

Ecology
Common pest of farmed abalone and oysters, but mainly on latter.  Boring stimulates the production of mudblisters. Occurs less often as epifauna on shells. Spread among farms via movement of infested farmed molluscs. Found in wild molluscs in Western and Eastern Cape provinces.

Reproduction 
Brood capsules joined, resemble sausage. Adelphophagic and planktotrophic larvae produced in separate broods. Brooding adults usually present during spring.