Broadening our knowledge of the Trachelophyllidae Kent, 1881 (Litostomatea, Ciliophora): Observations on known species of three genera and a new genus and species from the Czech Republic

Abstract

Trachelopyllidae Kent, 1881 is a family of predatory litostomatean ciliates distinguished by a three-rowed dorsal brush composed of two dikinetidal rows and one monokinetid row, and one or more types of organic epicortical scales called lepidosomes. To date, the taxonomy of the nine genera comprising the family has been based, almost exclusively, on the types of scales and their combinations together with cell morphometry. Six of the nine genera are monotypic. To date, molecular data has been available from only four species representing two genera. With the aim of broadening the molecular characterization of the Trachelophyllidae, we present new rRNA cistron sequences of three trachelophyllid species from Idaho, USA, identified by scanning electron microscopy and representing three genera of the family not yet sequenced, and we describe a novel species representing a new genus from the Czech Republic. The results confirm the extraordinarily conserved nature of the 18S rRNA gene and ITS2 regions in the Trachelophyllidae and demonstrate the discordance between lepidosome-based taxonomy and the rRNA cistron-based molecular phylogeny in this group. Additionally, we consider ciliary ultrastructural features unique to members of the Trachelophyllidae and Lingulotrichidae (suborder Trachelophyllina Grain, 1994).