Abstract
So far, no molecular investigations have been carried out on the systematically uncertain ciliate Epiclintes in spite of the recent reviews. In an attempt to solve this problem, we sequenced the small subunit ribosomal RNA gene of two forms of Epiclintes: E. auricularis auricularis and E. auricularis rarisetus. Phylogenetic trees were then constructed by means of bayesian inference (BI), maximum-likelihood (ML), maximum parsimony (MP), and neighbor-joining (NJ) methods in order to test previously presumed phylogenetic assignments of Epiclintes based on morphological and morphogenetic data. The main results are that the two isolates form a branch that is peripheral to all other typical stichotrichs. Epiclintes branched off first in all analyses performed with high BI and moderate MP supporting value (100% BI, 58% MP) while low ML and NJ supporting value (< 50%). This suggests that this genus could represent a unique taxon considering its systematic position. Morphological and ontogenetic investigations on Epiclintes auricularis indicates that this genus demonstrates several special features compared with most other related urostylids: (1) several (instead of one) left-most frontal cirri arc developed from the FVT anlage I in E. auricularis rarisetus; (2) buccal and frontoterminal (or migratory) cirri are lacking at interphase and never occur during divisional processes; (3) each FVT anlage, except the anlage 1, develops a transverse cirrus; and (4) anlagen for both marginal rows and dorsal kinetics are formed de novo. Based on both morphological/morphogenetical and molecular data available, Epiclintes might represent an individual taxon at suborder level, i.e., Epiclintina Wicklow, 1983 (nom. nud.) and as a peripheral branch within stichotrichs s. str.