The systematic significance of palp morphology in the polydora complex (Polychaeta : spionidae)

The palp morphology of Dipolydora coeca, D. quadrilobata. Polydora ciliata, P. cornuta and Pseudopolydora pulchra were studied with light and scanning electron microscope. Two new palp characters were found on the two species of Dipolydora: randomly scattered motile cirri and glandular holes. The pa lp morphology of the investigated species is compared with earlier reports on other members of the Polydora complex. Congeneric palp similarities are found in Polydora and Dipolydora. A single exception is the aberrant Dipoly dora commensalis. which has a distinctive palp morphology not found in any other spionid. The palp morphology of the two closely related genera Dipoly dora and Polydora is significantly different, which supports the validity o f the recently resurrected genus Dipolydora. Comparative studies indicate t hat the palp morphology of Pseudopolydora pulchra closely resembles that of Dipolydora. The recently studied palp morphology of Boccardia polybranchia has many similarities with that of Polydora.