?Polydora haswelli Blake and Kudenov 1978

Status
Rare, non-indigenous, pest

Description
38 mm for 193 chaetigers. Prostomium bilobed, caruncle to end chaetiger 3 or 4. 2 pairs of eyes arranged in trapezoid. In life dark pigment along the lateral margins of the prostomium, dark patches on the peristomium and at the base of the notopodial lobes of chaetigers 1 – 4; smaller, lighter spots on chaetigers 5 & 6. Some pigmentation around mouth and along anterior mid-ventral line.  Palps with dark bands.
No notochaetae on chaetiger 1. Modified spines of chaetiger 5 slightly curved with small accessory tooth in concave side. Hooded hooks start on chaetiger 7, up to 10. Sometimes accompanied by fine companion chaetae. Branchiae start on chaetiger 7, last 5 chaetigers abranchiate; don’t touch along mid-dorsum.
Pygidium saucer-shaped.

Ecology
Bores into shell of scallop, Pecten sulcicostatus and cultured oyster, Crassostrea gigas.

Distribution
South Africa: False Bay, Northern Cape Province
Japan, New Zealand, Australia, China, Korea, possibly Brazil

Note
Molecular evidence confirms that it is not indigenous. Identity needs clarification as it also resembles P. neocaeca closely.

Cite as: Malan, A. and Simon C.A. (2019), Polydora haswelli Blake and Kudenov 1978, modified May 2019, (https://thesimonpolychaetelab.com/polydora-haswelli/, Accessed on <day/month/year>)