KENTROPHOROS (CILIOPHORA, KARYORELICTEA) HAS ORAL VESTIGES - A REINVESTIGATION OF KENTROPHOROS-FISTULOSUS (FAURE-FREMIET, 1950) USING PROTARGOL IMPREGNATION

The morphology, infraciliature, and epibiontic bacteria community of K entrophoros fistulosus (FAURE-FREMIET, 1950) were studied in live cell s, in protargol impregnated specimens, and with the scanning electron microscope. Kentrophoros fistulosus is involuted tube-like, except for the body ends; the right side bears many longitudinal ciliary rows, t he involuted left side is sparsely ciliated and covered with few, thin spirilla and countless rod-shaped sulphur bacteria which are phagocyt ised through the cell surface. Thus, Kentrophoros has been considered to be secondarily mouthless. The infraciliature consists of dikinetids throughout. The anterior dikinetids of the right side are specialized , i.e. more closely spaced and have both basal bodies ciliated, obliqu e axes, and nematodesmata-like fibres forming a basket-like structure. These specializations are considered to be vestiges of an oral infrac iliature. The posterior end also has specialized dikinetids which give rise to a tuft of caudal cilia whose basal bodies are associated with conspicuous fibres extending into the tail. The left side seemingly h as two ciliary rows extending along the cell margins. However, detaile d analysis showed that these rows are very likely a single kinety curv ing around the cell. The bacterial lawn is embedded in a thick layer o f mucus, produced by the ciliate to keep the symbiotic kitchen garden in place. The data emphasize the loxodid relationship of Kentrophoros, earlier proposed by KAHL and RAIKOV, and suggest synonymizing K. long issimus (DRAGESCO) and K. tubiformis (RAIKOV & KOVALEVA) with K. fistu losus (FAURE-FREMIET). Improved diagnoses are provided for the family Kentrophoridae JANKOWSKI and the genus Kentrophoros SAUERBREY. The nom enclature of Kentrophoros is revised, i.e. correct names, dates, and a uthorships are given for all species described.