Imposex in Thais gradata and Chicoreus capucinus (Mollusca, Neogastropoda, Muricidae) form the Staits of Johor: A Case Study using Penis Length, Area And weight as Measures of Imposex Severity

摘要

Imposex, or the presence of a pseudopenis in female snials, is quantified by comparing the length of the female pseu- dopenis with the male penis. However, many muricid gastropods in the Malayan archipelago possess penes that are flagellate and coiled, making linear measurement difficult under the microscope. In addition, it is unclear if penis length I dependent on shell size. Accurate assess- ment of penis size is a necessary step towards determining the severity of imposex (and implicitly, the amount of organotins from antifouling paints that is associated with this phenomenon).