Functional morphology of mouthparts and gastric mill of Ibacus peronii (Leach) (Palinura : Scyllaridae)

Abstract

I. Peronii is a scavenger on small benthic invertebrates and animal remains. The mouthparts are less complex than those of some palinurans, as shown by their simple setation and fusion of endites, but have a broad endopod on the third maxillipeds. In the maceration and ingestion of soft animal remains, the mouthparts function as in other palinurans. How the mouthparts collect small prey is not yet known. The proventriculus of I. Peronii is simplified in the number, size and structure of its ossicles as compared with Jasus novaehollandiae and J. lalandei. The action of the gastric mill in I. Peronii is described. The relation between mouthpart structure, proventriculus structure and diet is discussed for I. Peronii and other palinurans. I. Peronii is specialized by simplification of the masticatory structures in relation to the soft and small animal food available at the surface of sublittoral sands and muds.