Functional morphology and feeding of donax serra rÖding and donax sordidus hanley (Bivalvia: Donacidae)

Abstract

The functional morphology of Donax serra and D. sordidus from South African beaches was examined, and comparative measurements made of the rate of water filtration. The two species differ in the structure and ciliation of the ctenidia, the number and spacing of the ridges on the labial palps, the direction of ciliary currents on the surface of the mantle and visceral mass, and the length and coiling of the mid-gut. The maximum rates of water filtration recorded showed similar relationships to size for the two species, but in D. sordidus the rate declined rapidly with time during the observations. These differences indicate differences in feeding strategy related to differences in distribution and behaviour of the two species on beaches. © 1981 The University of Chicago Press.