Pleurotricha curdsi

Xu, Yuan, Li, Lifang, Fan, Xinpeng, Pan, Hongbo, Gu, Fukang & Al-Farraj, Saleh A., 2015, Systematic Analyses of the Genus Architricha and Pleurotricha curdsi (Ciliophora, Oxytrichidae), with Redescriptions of Their Morphology, Acta Protozoologica 54 (3), pp. 183-193 : 191

Phylogeny of Pleurotricha curdsi and Architricha

Previous studies (e.g., Schmidt et al. 2007, Chen et al. 2013a, b, Lv et al. 2013, Kumar et al. 2014) have found that the family Oxytrichidae is not monophyletic, which is supported by our studies. The new population of Pleurotricha curdsi clusters well with its congener P. lanceolata , the type species of Pleurotricha , which validates the accuracy of the transfer based on morphological evidence ( Gupta et al. 2003), and reveals that the genus Pleurotricha is monophyletic. The genus Architricha is represented by the sole species A. indica , which has a flexible body and typical Oxytricha FVT and dorsal ciliature patterns. Shi (2000) and Song (2001) suggested assigning the oxytrichids with multiple marginal rows (MMR) to the family Pleurotrichidae . However, this idea is not supported by our phylogenetic trees, as the genera Architricha , Pleurotricha , Ponturostyla , and Onychodromopsis which possess MMR distribute in different clades of Oxytrichidae . Gupta et al. (2006) pointed out the ontogenesis of MMR in oxytrichids includes four modes: Architricha mode, Pleurotricha mode, Coniculostomum mode and Ponturostyla mode. But, unfortunately, the topology of the phylogenetic trees does not reflect the relationship of these modes either, For example, Pleurotricha and Onychodromopsis share the Pleurotricha mode, but they were quite far apart in the tree. Gupta et al. (2006) also indicated that Architricha mode, i.e. five marginal rows generating from five independent primordia, is plesiomorphy of these four modes. However, this opinion is not supported by our phylogenetic trees, as the clade including Architricha forms a sister branch to the clade including Onychodromopsis . The reason might be that the SSU rRNA gene cannot reflect the evolutionary history of the marginal rows. Considering that recent studies have gradually demonstrated that even very reliable features might evolve convergently, in order to fully understand the systematic position of the members in Oxytrichidae and their closely related taxa, a large sampling range based on multiple gene analyses, along with exploration of morphogenesis patterns, are greatly needed in further studies ( Gupta et al. 2006, Schmidt et al. 2007, Foissner and Stoeck 2008, Jung et al. 2014).