Presenter(s): Christina Ellison − Marine Biology
Faculty Mentor(s): Richard Emlet
Poster 59
Research Area: Natural Science
Funding: National Science Fund (REU program)
Chitons are marine molluscs in the class Polyplacophora. Like many marine organisms, chitons have a pelagic, dispersive larval stage which settles and metamorphoses into an adult form that lives on the benthos. During development, chitons must acquire structures that enable them to function in each of these environmental contexts. While many features of development have been well documented, one structure has yet to be reported. Chiton larvae consistently form a pair of birefringent, crystalline structures, best viewed with cross-polarized light. What they are made of and their function in the animal are unknown. The location and timing of these structures appear consistent with the “larval kidneys” as described by Baeumler et. al 2011, so we hypothesized they could be involved in kidney function. The purpose of this study was to establish a developmental timeline for these structures, to determine their chemical composition, and to record morphological data concerning their appearance (size, shape, number, location). This was achieved by raising chiton larvae and monitoring their development through microscopy. Calcein-tagging, fluorescence microscopy, and a murexide test were used to infer chemical composition. Our results suggest the structures form 4 days post-fertilization and persist at least 5 days after metamorphosis. The structures are composed of many small, calcium-containing crystals. They have been observed in 7 species across 2 suborders and may be a universal feature of chiton development. Our findings are consistent with possible kidney involvement, but functional studies must be done to further support this idea.