Meeting Abstract

P2.92  Saturday, Jan. 5  The ‘assassin’ snail, Clea (Anentome) helena (Gastropoda: Buccinidae), as a model for developmental and environmental physiology NEWEL, M.S.*; BOURNE, G.B.; Univ. of Calgary, AB, Canada; Univ. of Calgary, AB, Canada bourne@ucalgary.ca

Clea helena is an unusual buccinid gastropod, as it has successfully invaded freshwater lakes and streams throughout Southeast Asia and Indonesia. The ability to eliminate other undesirable snails (hence ‘assassin’) and scavenge carrion have made these snails popular among aquarium hobbyists, but their treatment in the scientific literature continues to be negligible. Thus, we combine observations of the behavior of captive snails, with descriptions of their morphology, reproduction and development. Usually, C. helena is found buried in the aragonite sand, which we use as our aquarium substrate. Once we introduce food the snails immediately emerge en masse and begin foraging, which suggests that they possess a keen olfactory sense. Our snails reach a maximum shell length of 15-20 mm and although their shells are thinner than those of similar marine species; they are quite robust compared to other freshwater snails. Otherwise, the morphology of ‘assassin’ snails is consistent with features typically ascribed to the Buccinidae. We observed that C. helena deposits isolated vasiform egg capsules, containing a single egg of 400-570 µm diameter. These capsules, which appear white to the naked eye but are nearly transparent when observed under the microscope, are 1-1.5 mm in length and height with convex sides marginally wider than the diameter of the enclosed egg. The encapsulated embryo undergoes complete non-feeding, benthic development and hatches as a crawl-away juvenile. Finally, we suggest that the ‘assassin’ snail should become a valuable model, providing a window into the features and mechanisms that have allowed certain caenogastropod molluscs to colonize and adapt to freshwater environments.