Feeding modes of deep-sea lobsters (Crustacea: Decapoda: Nephropidae and Palinuridae) in Northwest Pacific waters: Functional morphology of mouthparts, feeding behaviour and gut content analysis

The setation of the mouthparts, gut contents and video recordings of live individuals of the deep-sea clawed lobsters (Nephropidae) Metanephrops formosanus, M. armatus and the spiny lobster (Palinuridae) Puerulus angulatus from northwest Pacific waters were analysed to get an insight into their feeding modes. A comparison of SEM photos shows a high degree of similarity between the morphology and setation of the mouthparts of M. formosanus and M. armatus, but that of P. angulatus was very different to Metanephrops. Serrate setae are most abundant on the feeding appendages of M. formosanus and M. armatus. The mouthparts of P. angulatus are dominated by simple and cuspidate setae. Gut contents of Metanephrops spp. contained small crustacean parts, fish and bivalves and a considerable amount of sediment (∼60% relative abundance). Guts of Puerulus contained mostly small pieces of fish and crustaceans and only a relatively minor amount of sediment (<10%). Video analysis revealed that the studied Metanephrops species are able to handle soft food items by cutting and abrading movements of the mouthparts. Puerulus would not feed on presented food items under lab conditions. The feeding appendages and their setation are clearly related to the feeding modes of the species studied. Both Metanephrops species have slender appendages with fine and sharp setae, suggesting it is a predator and/or scavenger on small crustaceans and ingest deposits to a limited extent. Puerulus angulatus has thick and shorter appendages with strong simple and cuspidate setae, possibly corresponding to a more predatory lifestyle.