Description of three new predator species of Litostomatea (Alveolata, Ciliophora), including sequencing and annotation of their mitochondrial genomes

Three new species of haptorian ciliates Lacrymaria venatrix sp. nov., Phialina famelica sp. nov., and Chanaea vermicularis sp. nov., recovered from water bodies of Tuscany, Italy, are described according to the standards of the Next Generation Taxonomy, which include morphology, ultrastructure, phylogeny, and associated microbial consortium analysis plus mitochondrial genome sequencing and annotation. Lacrymaria venatrix is a species with a small spindle-shaped trunk, a highly contractile neck that equals the trunk in length at its full extension, and a macronucleus consisting of two nodules; it is mostly similar to L. songi but diverges in the denser ciliature, the closer macronuclear nodules, and the single micronucleus. Phialina famelica has a blunter spindle-shaped trunk with a shallow oral bulge and an elongated macronucleus; it is mostly similar to P. salinarum and P. serranoi , but differs in the freshwater habitat, and by having fewer but denser kineties. Chaenea vermicularis differs from its congenerics by a modest contractility combined with a greater elongation ability, the mucocysts organized into multiple rows forming stripes, and the several hundreds of macronuclear nodules. The 18S rDNA-based phylogenetic analysis supports previous observations of the paraphyly of the genera Lacrymaria and Phialina , that need a deep systematics revision. The genus Chaenea seems not to be challenged, though its position within Haptoria remains not fully clear, and C. vermicularis sp. nov. appears rather divergent from its congeners.