?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.

Relevant papers:

Blake, J. A. and Kudenov, J.D. (1978) The Spionidae (Polychaeta) from southeastern Australia and adjacent areas with a revision of the genera. Memoirs of the Natural Museum of Victoria 39, 171-280

Read, G.B. (2010) Comparison and history of Polydora websteri and P. haswelli (Polychaeta: Spionidae) as mud-blister worms in New Zealand shellfish. New Zealand Journal of Marine and Freshwater 44, 83-100.

Walker, L.M. (2014) A revision of the Polydora-complex (Annelida: Spionidae) fauna of Australia. PhD thesis. University off Queensland, Australia.

Williams, J.D. and Radashevsky, V.I. (1999). Morphology, ecology, and reproduction of a new Polydora species from the east coast of North America. Ophelia 51(2): 115-127

Cite as: Van Niekerk, S. and Simon C.A. (2012), Polydora haswelli/neocaeca Blake and Kudenov 1978/Williams and Radashevsky 1999 modified May 2019 by A. Malan, The Simon Polychaete Lab – http://www.thesimonpolychaetelab.com/polydora-haswelli/