deMaintenon, M.J.: Patterns of reproductive system development in the caenogastropods; systematic and evolutionary implications.

The reproductive system is one of the most complex and variable of gastropod organ systems, and is often also the last organ system to develop. The level of anatomical variation of the reproductive system, coupled with its late development, renders it an interesting system to investigate for evolutionary changes in organogenetic patterns. Patterns of reproductive system organogenesis are compared in several representative caenogastropod species, relative to existing hypotheses of caenogastropod evolution. I am primarily interested in two questions: 1) How much temporal variation do caenogastropod taxa exhibit in the reproductive organogenetic sequence; and 2) How are patterns of temporal variation in the organogenetic sequence related to qualitative variations in adult reproductive anatomy between caenogastropod taxa? Paedomorphotic heterochronic events are thought to be common in gastropod evolution, however this hypothesis has been difficult to test. Comparison of organogenetic sequences within a phylogenetic framework allows the predominance of different types of heterochronic patterns to be addressed.