Phylogeny and reproduction in Syllidae (Polychaeta)

The phylogeny of 12 representatives of the four syllid subfamilies is analysed using 44 morphological characters and 96 character states. The analysis is designed to answer two questions: are the four subfamilies monophyletic, and how are the different reproductive strategies related? Syllids show two modes of reproduction, epigamy and schizogamy. Epigamy is mainly constrained to two of the four subfamilies, Eusyllinae and Exogoninae but occurs also in some members of Autolytinae. Schizogamy can be of two types-scissiparity and gemmiparity-and both types are found in Syllinae and Autolytinae. Several modes of brood protection also occur in the family; in some epigamous species the eggs and even juveniles are attached to the main animal, whereas in brooding schizogamous species the stolons care for the young. Brood protection appears in Exogoninae, a few species of Eusyllinae, and some Autolytinae. The resulting tree indicates that members exhibiting brood protection are constrained to one clade, and that it is uncertain whether epigamy or schizogamy is the plesiomorphic reproductive mode. Three of the four subfamilies, Autolytinae, Exogoninae and Syllinae, are supported in the analysis whereas Eusyllinae is found to be polyphyletic. (C) 1999 The Linnean Society of London.