Functional morphology of the mouthparts and alimentary tract of the slipper lobster Thenus orientalis (Decapoda : Scyllaridae)

The mouthparts and proventriculus of Thenus orientalis Lund are adapted to ingest soft flesh, which is consistent with the diet of this and other scyllarids. The crista dentata are reduced, with food transfer into the oesophagus facilitated by large stout setae on the second and third maxillipeds. The mandibles exert little force and most food maceration is effected by the gastric mill. Ingestion is aided by mucus secreted by rosette glands in the paragnaths and membranous lobe, as well as expansion of four longitudinal folds in the oesophageal wall. The cardiac stomach has considerable food storage capacity by extension of its membranous walls, reduced ossicles and simplified ventral filtration channels. The filtering ability of the pyloric filter press is consistent with other macrophagous decapods. The dorsal caecum above the pyloric stomach has an absorptive columnar epithelium that contains acid mucin granules and protein. Muscular walls and longitudinal folds in the hindgut facilitate faecal pellet extrusion.