The True Diversity of Devescovinid Flagellates in the Termite Incisitermes marginipennis

More than 40 years ago, ten species of devescovinid flagellates were described to occur in the gut content of the termite Incisitermes marginipennis. Based on light microscopic examinations, the flagellates were then classified into the two genera Devescovina and Metadevescovina. Here, we combined molecular phylogenetic analysis of the small subunit rRNA genes of the gut flagellates with the first ultrastructural investigation of the genus Metadevescovina. Our results suggest that I. marginipennis contains only one species of devescovinid flagellates, Metadevescovina modica, which comprises three variants of the same phylotype (⩾99.5% sequence similarity). Monophyly of all Metadevescovina sequences obtained from Pterotermes and Incisitermes species in this and previous studies and the absence of filamentous bacterial epibionts typical of Devescovina species (M. modica is densely colonized with spirochetes) corroborate the validity of the genus Metadevescovina and allow its differentiation from other genera of devescovinid flagellates.