Metaradiophrya varians
Creators: name: Obert, Tomáš
name: Vďačný, Peter
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Protozoa
Ciliophora
Oligohymenophorea
Astomatida
Radiophryidae
Metaradiophrya
Metaradiophrya varians

description: Metaradiophrya varians (de Puytorac, 1954)
Figs 6, 7
Description
The body size is about 110–180 × 85–95 µm. The body shape is ovate to elliptical with an anterior body end rounded and posterior end broadly rounded to truncate. The cell is distinctly dorsoventrally flattened (Figs 6A, F–I, 7A, D). The fibrillar hook is localized about 10 µm away from the anterior body end. Its longer arm measures on average 30 µm, while its shorter arm only 11 µm. The hook appears slightly flatter than in the previous species and the thickened base of the shorter arm has been never observed. There are 5 or 6 fibers attached to the upper right side of the longer arm, on average 26 (22–29) fibers to the ventral side of the longer arm and 11 or 12 fibers to the left side of the shorter arm (Figs 6 A–C, 7B). The nuclear apparatus consists of a single macronucleus and a single micronucleus. The macronucleus commences on average 25 µm away from the anterior body end and terminates on average 11 µm away from the posterior body end. The size of macronucleus is about 80–140 × 10–15 µm. The macronucleus extends through cell’s midline. The micronucleus reaches a diameter of 6–8 µm and is situated close to the macronucleus about in its mid-portion (Figs 6 D–I, 7A, D).
There are two staggered rows of contractile vacuoles arranged along the right and left side of the macronucleus: 5–8 vacuoles in the right row and 6 or 7 vacuoles in the left row (Figs 6A, E–I, 7A, D). The cytoplasm is colorless and studded with granules about 0.5 µm across. The cortex is rigid and without granules (Fig. 7B). Swims moderately fast by rotation about the main body axis.
Somatic ciliature is holotrichous and composed of very densely ciliated and narrowly spaced kineties. The ventral ciliature is interrupted by a subapical suture extending from the right body margin over the fibrillar hook to the left body margin. Somatic kineties above the suture run towards the anterior body end where they curve onto the dorsal body side to meridionally extend over its surface towards the posterior body end. Somatic kineties below the suture run meridionally over the ventral side towards the posterior body end (Figs 6 A–B, 7B–C). The number of ventral kineties ranges from 50 to 64 on the ventral side and from 53 to 64 on the dorsal side. There is a subterminal suture on the left and the right side of the body.
Occurrence
Metaradiophrya varians was solely recorded in the epigeic E. fetida at two comparatively distant localities, i.e., in compost heaps in the Jakubská ulica street in Rača and in the Botanical Garden of Comenius University (Fig. 1; Table 2). Metaradiophrya varians inhabited only the middle part of the gastrointestinal tract and there were usually ten exemplars per earthworm. Our data on occurrence of M. varians and M. lumbrici indicate that both species are specialized on different ecological groups of host oligochaetes. The ecologically different L. terrestris and E. fetida never contained the same species of Metaradiophrya, even when they originated from closely situated localities or when they were cocultivated in the laboratory.
description: Published as part of Obert, Tomáš & Vďačný, Peter, 2019, Integrative taxonomy of five astome ciliates (Ciliophora, Astomatia) isolated from earthworms in Central Europe, pp. 1-37 in European Journal of Taxonomy 559 on pages 12-15, DOI: 10.5852/ejt.2019.559, http://zenodo.org/record/3474872