The functional morphology of the feeding and grooming appendages of Ebalia tuberosa (Pennant) (Crustacea : Decapoda : Leucosiidae)

Abstract

Ebalia tuberosa feeds mainly on small invertebrates but will also scavenge. The morphology of the feeding and grooming appendages is described paying particular attention to the structure and distribution of the setae. The movements of the various appendages during feeding are analysed. The mouthparts function in manipulating, grasping and cutting the food; in forming setal screens which prevent food from falling out of the mouth region; in creating water currents to waft away rejected material; and in cleaning each other. Setal structure is correlated with function. Those appendages which manipulate the food are armed with cuspidate and serrate setae while those which hold the food string steady during cutting carry plumodenticulate setae. Plumodenticulate and serrulate setae of various types make up two buccal setal screens, one transverse and the other longitudinal. The rejection current is generated by the flagella of the exopodites of the 1st and 2nd maxillipeds which bear long plumose setae. The main cleaning appendages are the 3rd maxillipeds whose distal segments bear serrate setae. In addition, various appendages bear fields of plumodenticulate setae which brush and clean adjacent surfaces during the normal feeding movements of the mouthparts.