Evaluating molecular support for and against the monophyly of the Peritrichia and phylogenetic relationships within the Mobilida (Ciliophora, Oligohymenophorea)

Abstract

Zhan, Z., Xu, K. & Dunthorn, M. (2012). Evaluating molecular support for and against the monophyly of the Peritrichia and phylogenetic relationships within the Mobilida (Ciliophora, Oligohymenophorea). —Zoologica Scripta,00, 000–000.An ongoing debate in ciliate molecular phylogenetic analyses is whether the Peritrichia – composed of the Sessilida and the Mobilida – are monophyletic. To further investigate this group, here we increase taxon sampling with four further mobilids: Trichodinella sp., Trichodina pectenis, Urceolaria serpularum and Urceolaria korschelti. Results show that support for and against monophyly of the peritrichs depends on different methods of alignment, and different methods of masking ambiguously aligned nucleotide positions. Results from constrained analyses also are dependent on different alignment and masking methods. We propose that there is no well‐supported SSU‐rDNA evidence supporting for and against the removal of the mobilids from the peritrichs. Within the Mobilida, we find that Trichodinella nest within Trichodina, Urceolaria branch basally, and Trichodina are non‐monophyletic, and suggest that Leiotrocha be formally transferred into Urceolaria. In addition, the data support that Urceolaria‐like denticles and Urceolaria‐/Trichodina‐like adoral ciliary spiral are plesiomorphic conditions within the mobilids.