Reproduction and Larval Development of Typosyllis pulchra (Berkeley & Berkeley) (Polychaeta: Syllidae)

Abstract

The reproductive biology of Typosyllis pulchra from the coast of Washington has been investigated based on observations of animals in the field and stolonization in the laboratory by both field-collected and cultured animals. Like most Syllinae, T. pulchra reproduces by stolonization, i.e., each individual produces 3-4 posterior, detachable, gamete-bearing stolons during consecutive 30-day intervals. Although some regenerating segments are incorporated into the stolons, in this species new stolons consist primarily of stock body segments. Reproductive animals occur in the field from late January through July; maximum reproductive activity is between April and June. Long days apparently promote reproduction, but lunar synchronization of spawning could not be demonstrated. Larval development is described based on light and scanning electron microscopy. Fertilization is external; developing larvae settle within 75 hr. The development of cephalic structures (eyes and antennae) is precocious compared to other Syllinae that have been studied, and the sequence of parapodium formation is unusual.