Phylogeny of some systematically uncertain-urostyloids Apokeronopsis, Metaurostylopsis, Thigmokeronopsis (Ciliophora, Stichotrichia) estimated with smallsubunit rRNA genesequence information:Discrepancies and agreements with morphological data

Abstract

The small subunit rRNA (SSrRNA) genes of seven species of urostyloids representing four genera were sequenced. Thesewere: Apokeronopsiscrassa, A. bergeri, Anteholosticha sp-QD-1, Metaurostylopsis sp-QD-1, M. sp-QD-2, M. sp- QD-3and Thigmokeronopsis sp-QD-1.Gene trees were constructed in order to investigate the irphylogenetic relationships. The results indicate that: (1) Apokeronopsis, Thigmokeronopsis and Metaurostylopsis form awell- supported, clearly isolated, monophyletic group; (2) Metaurostylopsis species analysed consistently group together indicating that it is a well-outlined genus; (3) the validity of the genus Apokeronopsis is supported; (4) the separation of Holosticha and Anteholosticha is supported although Anteholosticha species exhibita high molecular diversity; (5) Pseudokeronopsis and Thigmokeronopsis, which have been considered closely related, may not share a recent common ancestor, casting doubt on the monophyly of the family Pseudokeronopsidae.