Functional mouthpart morphology of the squat lobster Munida sarsi, with comparison to other anomurans

The mouthparts of Munida sarsi Huus, 1935, including the labrum and paragna ths, are described using LM and SEM, with special attention to the setal co mposition and its function. We also used high-resolution macrovideo equipme nt to record the feeding processes and monitor setae in action. This combin ation of morphological and preliminary behavioral data enabled us to arrive at a more comprehensive understanding of the functional morphology. M. sar si was found to be an opportunist and capable of handling and eating most k inds of animal tissue. The species can also be a selective deposit feeder, sorting the sediment by quality and not by size. This sorting is performed by the setae on the medial rim of the bases of maxilla 1, maxilla 2 and max illiped 1. Many of the other mouthpart functions ranging from food detectio n to ingestion are mapped with comparison to what has been found for other anomurans. Grooming was shown to be a significant function of many mouthpar ts: especially the endopod of maxilliped 3. In general the mouthparts close st to the mouth have the least complex movements and functional scheme, wit h the mandibles being able to perform only one movement, i.e. cutting or cr unching food objects. Some functions are attributed to the paragnath, the e ndopod of maxilla 2 and the epipod of maxilliped 1.