Sediment “whips”: Amphipod artefacts from the rocky sublittoral in Britain

Sediment whips are reported attached to hydroids from circalittoral boulder grounds off St. Abbs, Scotland which are thought to be artefacts constructed by the amphipod Dyopedos porrectus Bate. Whips have been photographed in situ supporting primarily Dyopedos, but additionally caprellid amphipods and the arcturid isopod Astacilla longicomis (Sowerby). Under the scanning electron microscope the surface of the whip is seen to be criss-crossed with a meshwork of microfibrils thought to be derived from dactylar secretions of peraeopods 3 and 4 of Dyopedos. These impart significant strength and flexibility to whips underwater. The function of a whip is thought to be that of a vantage point for suspension-feeding.