Updating the Trachelocercids (Ciliophora, Karyorelictea)IIIRedefinition of the Genera Trachelocerca EHRENBERG and Tracheloraphis DRAGESCO, and Evolution in Trachelocercid Ciliates

Abstract

The morphology and infraciliature of Trachelocerca sagitta (MÜLLER, 1786) EHRENBERG, 1840, Tditis (WRIGHT, 1982) novcomb., Tracheloraphis phoenicopterus (COHN, 1866) DRAGESCO, 1960, Taragoi (DRAGESCO, 1954) DRAGESCO, 1960, Tlongicollis (DRAGESCO, 1960) novcomb., and Toligostriata (RAIKOV, 1962) novcombwere studied in live and protargol impregnated specimens, as well as with the scanning electron microscopeNeotype slides with protargol impregnated specimens of each species have been deposited in (LI)The somatic and oral infraciliature of the species investigated basically agrees with that of Trachelolophos and PrototrachelocercaSpecifically, all have a glabrous stripe bordered by a peculiar (bristle) kinety composed of dikinetids having a unique ciliation and flbrillar systemFurthermore, all trachelocercids have specialized structures at the anterior end of the body, highly reminiscent of a prostome and/or gymnostome oral apparatusSome of the species investigated represent the types of the genera Trachelocerca EHRENBERG, 1840 (Tsagitta), Tracheloraphis DRAGESCO,1960 (Tphoenicopterus), and Trachelonema DRAGESCO, 1960 (Tlongicollis), three taxa often confused due to the vague original diagnosesOur study provides accurate characteristics for distinguishing Tracheloraphis (with brosse) from Trachelocerca (without brosse), while the genus Trachelonema is synonymized with Tracheloraphis because of distinct similarities in the infraciliatures of the type speciesAccordingly, three well-defined genera are recognized in the family Trachelocercidae KENT, 1881: Trachelocerca EHRENBERG, 1840, Tracheloraphis DRAGESCO, 1960, and Trachelolophos FOISSNER & DRAGESCO, 1996The order Trachelocercida JANKOWSKI, 1978 is redefined using the glabrous stripe, the bristle kinety, and the apical location of the oral apparatus as unique character constellationHENNIG's cladistic method suggests that the Trachelocercidae evolved from the Prototrachelocercidae and both have a common ancestor with the LoxodidaSome minor taxonomic changes (new combinations) and many nomenclatural emendations have been made.