Redescription of Lagenophrys maxillaris (Jankowski, 1993) (Ciliophora, Peritrichia, Lagenophryidae), an ectosymbiont of marine amphipods

The loricate, peritrich ciliate Lagenophrys maxillaris, a highly specialized ectosymbiont of marine gammarid amphipods, was examined and redescribed by using material from museum collections to make hematoxylin and protargol preparations. The infraciliature is described for the first time, and the shape of the macronucleus was found to differ significantly from the shape given in the original description. Lagenophrys maxillaris is one of only four species of Lagenophrys known to occur on the maxillipeds of amphipods or isopods and differs from the others with respect to the structure of the lips of the lorica aperture and pattern of infundibular polykinetids. It appears to prefer attaching to hosts that live in water deeper than that inhabited by hosts of other known marine species of Lagenophrys and was recorded from one sample of Gammarus locusta taken at a depth of 240-250 m. Lagenophrys maxillaris seems to be restricted to G. locusta and G. oceanicus although three other closely related species of Gammarus are available as hosts. Host specificity is possibly the result of trophic differences, possibly related to depth of habitat, between the two hosts and their congeners.