Molecular phylogeny ofNothoholosticha(Protozoa, Ciliophora, Urostylida) and systematic relationships of theHolosticha-complex

Abstract

The marine ciliate Nothoholosticha is characterized by having a Holosticha-like ciliature pattern but without migratory frontoterminal cirri. However, its systematic position and its relationship to other members of the Holosticha-complex have not yet been resolved. In order to gain deeper insights into these relationships, the small subunit rRNA (SSrRNA) gene and the rRNA internal transcribed spacer and 5.8SrRNA (ITS1-5.8S-ITS2) region of two marine Anteholosticha species, as well as the ITS1-5.8S-ITS2 region of N. fasciola, were sequenced, and molecular trees (BI, ML, NJ and MP trees) were constructed. Although our analyses failed to conclusively resolve the phylogeny of this assemblage, certain conclusions could be drawn. Firstly, Nothoholosticha is a valid genus that is more closely related to Pseudokeronopsis than to other Holosticha-complex genera. Secondly, sequence analyses and phylogenetic trees of several Anteholosticha species revealed a high molecular diversity, which does not support the monophyly of this genus. Thirdly, the current assignment of certain well-known genera, e.g.

Morphology and 18S rDNA phylogeny of Hemicycliostyla sphagni (Ciliophora, Hypotricha) from Brazil with redefinition of the genus Hemicycliostyla

“…This is basically due to the position of Apokeronopsis spp.+Thigmokeronopsis stoecki Shao et al, 2008, away from Pseudokeronopsis spp., a phylogenetic pattern that is consistent with previous studies (e.g. Yi et al, 2008aYi et al, , 2010Li et al, 2010a). The 18S rDNA sequences of H. sphagni and H. franzi were 98 % similar and differed from that of P. cristata by 8.1 and 6.5 %, respectively.…”

Evolution of the Order Urostylida (Protozoa, Ciliophora): New Hypotheses Based on Multi-Gene Information and Identification of Localized Incongruence

“…This report also included a description of morphogenesis and the unusual mode of formation of left marginal rows, which has been reported in only another hypotrich genus, that is, Pseudourostyla . However, the present and previous molecular investigations [4], [12], [22], [23], [27], [40], [57], [58] did not recover a close relationship between Diaxonella and Pseudourostyla , thus supporting Berger's [9] hypothesis that this unusual morphogenetic process is very likely a result of convergent evolution and should not be regarded as a family level character as suggested by Eigner and Foissner [8]. In addition, the placement of Diaxonella in family Holostichidae (sensu Berger [9]) is also clearly rejected by the molecular data in both the present and previous investigations [4], [12], [22], [23], [27], [40].…”

Taxonomy, ontogeny and molecular phylogeny of Anteholosticha marimonilata spec. nov. (Ciliophora, Hypotrichida) from the Yellow Sea, China

“…Of these, only six species have been described in detail in terms of their morphogenetic processes and likewise SSU rRNA gene sequence data are also only available for six species (Berger, 2006;Chen et al, 2010). Based on this limited morphogenetic and molecular information, the genus Anteholosticha does not seem to be monophyletic (Berger, 2006;Chen et al, 2010;Yi et al, 2010;Schmidt et al, 2007). In order to verify this conclusion, and to increase our knowledge and understanding of the systematics and biodiversity of the genus Anteholosticha, morphogenetic and molecular studies of a wider range of species are needed.…”