UPDATING THE TRACHELOCERCIDS (CILIOPHORA, KARYORELICTEA) .3. REDEFINITION OF THE GENERA TRACHELOCERCA EHRENBERG AND TRACHELORAPHIS DRAGESCO, AND EVOLUTION IN TRACHELOCERCID CILIATES

The morphology and infraciliature of Trachelocerca sagitta (MULLER, 17 86) EHRENBERG, 1840, T. ditis (WRIGHT, 1982) nov. comb., Tracheloraphi s phoenicopterus (COHN, 1866) DRAGESCO, 1960, T. aragoi (DRAGESCO, 195 4) DRAGESCO, 1960, T. longicollis (DRAGESCO, 1960) nov. comb., and T. oligostriata (RAIKOV, 1962) nov. comb. were studied in live and protar gol impregnated specimens, as well as with the scanning electron micro scope. Neotype slides with protargol impregnated specimens of each spe cies have been deposited in (LI). The somatic and oral infraciliature of the species investigated basically agrees with that of Tracheloloph os and Prototrachelocerca. Specifically, all have a glabrous stripe bo rdered by a peculiar (bristle) kinety composed of dikinetids having a unique ciliation and fibrillar system. Furthermore, all trachelocercid s have specialized structures at the anterior end of the body, highly reminiscent of a prostome and/or gymnostome oral apparatus. Some of th e species investigated represent the types of the genera Trachelocerca EHRENBERG, 1840 (T. sagittal, Tracheloraphis DRAGESCO, 1960 (T. phoen icopterus), and Trachelonema DRAGESCO, 1960 (T. longicollis), three ta xa often confused due to the vague original diagnoses. Our study provi des accurate characteristics for distinguishing Tracheloraphis (with b rosse) from Trachelocerca (without brosse), while the genus Trachelone ma is synonymized with Tracheloraphis because of distinct similarities in the infraciliatures of the type species. Accordingly, three well-d efined genera are recognized in the family Trachelocercidae KENT, 1881 : Trachelocerca EHRENBERG, 1840, Tracheloraphis DRAGESCO, 1960, and Tr achelolophos FOISSNER & DRAGESCO, 1996. The order Trachelocercida JANK OWSKI, 1978 is redefined using the glabrous stripe, the bristle kinety , and the apical location of the oral apparatus as unique character co nstellation. HENNIG'S cladistic method suggests that the Trachelocerci dae evolved from the Prototrachelocercidae and both have a common ance stor with the Loxodida. Some minor taxonomic changes (new combinations ) and many nomenclatural emendations have been made.