Morphology of a calceolus, an antennal receptor of gammaridean Amphipoda (Crustacea)

Abstract

The internal structure of calceoli, in the gammaridean amphipod, Eusirus perdentatus Chevreux, has been examined for the first time using fast atom etching in conjunction with scanning electron microscopy. The etching technique was used to remove surface layers of the calceolus, revealing a complex array of cuticular fibres supporting the proximal cup and distal plates. The cup was found to consist of a radial set of about 200 rod-like subunits. The results add weight to the view that calceoli may function as phonoreceptors, sensitive to water borne pressure waves.