Meeting Abstract
P3.33 Tuesday, Jan. 6 Observations on the functional morphology of the Pacific geoduck clam, Panopea abrupta (Conrad, 1849) NEWEL, M.S.; MARTIN, K.M.F.; BOURNE, G.B.**; University of Calgary, Alberta, Canada; University of Calgary, Alberta, Canada; University of Calgary, Alberta, Canada bourne@ucalgary.ca
Reports suggest that the Pacific geoduck, Panopea abrupta, is the largest and most long-lived burrowing clam in the world. Although this species is the target of an important commercial fishery and growing aquaculture efforts, many aspects of their basic biology remain undescribed. We combined observations of the behaviour of captive specimens, with a series of dissections and a three-dimensional computer reconstruction of the entire animal, as well as select isolated anatomical features, to illustrate aspects of their functional morphology. Within the fused mantle cavity of the geoduck, the anterior portion contains a large, globose visceral mass, a set of paired, robust labial palps and a reduced foot that functions as a plunger that pushes any accumulated detritus out the pedal aperture. The posterior portion of the mantle cavity is dominated by the infra- and suprabranchial chambers, separated by a comparatively small ctenidium, and dorsally a relatively inconspicuous heart/kidney complex located beneath elements of the hinge. Undoubtedly the most prominent element of geoduck morphology is the extremely large, muscular and completely fused siphons, which has previously been purported to be capable of generating considerable water pressures and flow rates. In addition, we observed that captive geoducks gain leverage from the siphon and move about a bare aquarium. This may provide a mechanism for at least limited postural and positional mobility in their natural habitat, as compensation for their reduced foot. Finally, we believe that a comprehensive description of the functional morphology of P. abrupta will lay the foundation for subsequent research into the biology of these fascinating and increasingly economically valuable animals.
