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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 7719

Yannick Maslin-Leny and Jacques Bohatier; [Cytologie Ultrastructurale de Trichodina et Tripartiella (Cilies, Peritriches)]. Protistologica XX(1):113-132, 1984

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Ultrastructural data concern Trichodina nigra, Tripartiella copiosa and T. kashkovskyi, epibionts of lagoon's fishes. For both the three species, the somatic ciliature (or trochal ciliature) is composed of three ciliated girdles separated by two cortical septa. The upper one is an only row of isolated kinetosomes (most of them are unciliated); the middle one is a juxtaposition of small oblique rows of ciliated kinetosomes; the lower one is an unique row of coupled ciliated kinetosomes. We cannot give a specific orientation to the upper and middle girdles in the absence of any associated microtubular structures. A short ribbon of transverse fibers is associated with each dikinetids of the lower girdle, which must be considered as a continuous circular kinety. In all cases the oral ciliature is compounded, on the right side, by a << stichodyade >> (peristomal and infundibular levels), and on the left side, by 3 << polykineties >> (Po) of unequal size. Each polykinety is made up of 3 parallel rows of ciliated kinetosomes. At the infundibular level no microtubular structures are seen in association with the kinetosomes of Po2-Po3 (exclusively infundibular) and Po1. At the peristomal level, short postciliary ribbons are carried by the outermost row of Po1 basal bodies (the right row); in addition, << dense fibers >> extend posteriorly from the innermost row of kinetosomes (the left one). A short << germinal kinety >>, which is a row of unciliated kinetosomes without associated microtubular ribbons, is visible along the outer side of the paroral ciliature but only at the peristomal level. A complex skeletal structure is characteristic of the adhesive disc. This radially symmetrical structure is made up from many subcomponents; from the center to the periphery, we can distinguish: << denticles >>, << primary radial fibers >>, << secondary radial fibers >>, which have not strickly the same morphology in the three species.