Abstract
Previous light-microscope studies of the relationships between feeding habits and mouthpart structures have suggested that copepods of the Family Pontellidae are carnivores. Scanning electron microscope studies of mouthparts of three pontellid species revealed that the mandibular blades
are complex three-dimensional structures which appear capable of macerating diatoms, and the setules of the 2nd maxillae are capable of retaining particles down to the 10-20 μm size range. Scanning electron microscope studies of the contents of fecal pellets show that these
copepods ingest and macerate diatoms in nature, and when fed unialgal diets. Animal remains were also observed in the natural-diet fecal pellets of all three copepod species. Thus, there is a mechanical basis, as well as direct evidence, for the feeding of these copepods as omnivores, even
though their family has been previously considered carnivorous.