Phylogenetic Relationships of the Subclass Peniculia (Oligohymenophorea, Ciliophora) Inferred from Small Subunit rRNA Gene Sequences

Abstract

Peniculine ciliates have been recognized as a distinct higher taxon of ciliates for almost 50 years. However, phylogenetic relationships within the Subclass Peniculia are still unsettled. To contribute to our understanding of their phylogeny and provide evidence for the position of Urocentrum turbo, we sequenced its small subunit (SS) rRNA gene and the SSrRNA genes from Lembadion bullinum, Frontonia sp., Paramecium caudatum, Paramecium multimicronucleatum, Paramecium putrinum, and Paramecium woodruffi. Urocentrum turbo was the only one of these species not to exhibit a shortened Helix E10_1, which we conclude characterizes the "higher" peniculines. Except for U. turbo, the peniculines are strongly supported as a monophyletic clade with Lembadion, Frontonia, and Paramecium species forming separate and strongly supported clades by bootstrap analysis using distance matrix, maximum parsimony, and maximum likelihood methods. Urocentrum turbo is associated with different lineages, depending upon the analysis used. The Paramecium species form at least four clades with the Paramecium aurelia subgroup being the most derived. We conclude that the Subclass Peniculia should be divided into two orders, the Order Urocentrida and Order Peniculida, with the latter order having two suborders, the Suborder Frontoniina and Peniculina. We place U. turbo with the peniculines because of shared morphological and stomatogenetic features.

Comparative analysis of the mitochondrial cytochromecoxidase subunit I (COI) gene in ciliates (Alveolata, Ciliophora) and evaluation of its suitability as a biodiversity marker

“…Although we do not have an explanation why Paramecium shows such a great divergence, we find the same pattern also in the SSrRNA gene sequences (Nanney et al, 1998;Strüder-Kypke et al, 2000a, 2000b. Paramecium multimicronucleatum shows intraspecific genetic divergences of 0.2-10.3%.…”

“…Within the subclass Peniculia, the genus Paramecium clusters as monophyletic taxon. The topology within the genus corresponds largely to SSrRNA gene sequence data (Strüder-Kypke et al, 2000a, 2000b.…”

Phylogenomic analyses reveal subclass Scuticociliatia as the sister group of subclass Hymenostomatia within class Oligohymenophorea

“…The phylum Ciliophora is divided into 12 classes of which the Oligohymenophorea is arguably the most diverse and is consistently recovered as a monophyletic group in molecular phylogenies (Miao et al, 2004;Miao et al, 2001;Sanchez-Silva et al, 2003;Struder-Kypke et al, 2000). The Oligohymenophorea has long attracted the attention of researchers for a variety of reasons, two of the main ones being: (1) the inclusion within this group of two model genera, namely…”

Supplementation with Sterols Improves Food Quality of a Ciliate for Daphnia magna

“…The inhibition of tetrahymanol production by exogenously supplied sterols has been extensively studied in T. pyriformis, an experimental model ciliate related to C. campylum (Class Oligohymenophorea, Subclass Hymenostomatia; e.g. Strü -der-Kypke et al 2000). Thereby, cholesterol, lathosterol, dihydrocholesterol, and several other sterols have been shown to inhibit tetrahymanol and diplopterol production (e.g.…”