Meeting Abstract

36.5  Wednesday, Jan. 5  The diverse roles of larval musculature and microfilaments during the initial stages of metamorphosis of marine bryozoans. SANTAGATA, S.; Long Island University scott.santagata@liu.edu

Marine bryozoan larval forms are noted for their rapid morphogenetic movements at metamorphosis. Previous work has documented the roles of ciliary motility, larval musculature, and dynamic bands of microfilaments in the rearrangement of larval and presumptive juvenile tissues during the formation of the preancestrula. However, the majority of this information was gathered using traditional histological and ultrastructural methods. Here, I use laser confocal microscopy and cytological probes for nucleic acids and actin to document the actions of muscles and microfilaments during metamorphosis of representative species from each of the major morphological grades of marine bryozoans. These results generally corroborate previous findings based on traditional histological methods, however greater diversity exists in the structural complexity of larval musculature and its role during metamorphosis in ctenostome and ascophoran grade bryozoans than previously documented. These new findings are also mirrored in the cellular complexity and morphogenetic movements of the largely undifferentiated tissues that comprise the cystid and polypide of the ancestrula. Lastly, the ability to follow the histolysis of larval tissues is greatly improved with the use of ubiquitous cellular probes and confocal microscopy. Future work will investigate mechanisms of cell death within the larval tissues at metamorphosis.