Hoplitophrya polymorphus Nana, Fokam et al., 2018

Nana, Paul Alain, Fokam, Zéphyrin, Viguès, Bernard, Bricheux, Geneviève, Aghaindum, Gidéon Ajeagah, Ngassam, Pierre, Nola, Moïse & Sime-Ngando, Télesphore, 2018, Morphology and infraciliature of two new earthworm ciliates, Hoplitophrya polymorphus sp. nov. and Anoplophrya simplex sp. nov. (Ciliophora: Oligohymenophorea: Astomatia), Zootaxa 4392 (1), pp. 169-178 : 171-173

Hoplitophrya polymorphus Nana, Fokam et al. sp. nov.

Description. This ciliate cohabits with other species of astome ciliates such as those of the genera: Almophrya ; Coelophrya ; Metaracoelophrya ; Dicoelophrya in the foregut and midgut of the earthworms Alma nilotica and Alma emini .

General morphology. This species displays two main forms: the elongated form measuring 150–247 µm in length and 40–87 µm in width ( Figures 2 A–C ), and the stocky form measuring 140–170 µm in length and 70–98 µm in width ( Figures 2 D–F ). The general morphology of the two forms is characterized by a curved cylindrical body shape with a rounded anterior pole and a narrower posterior pole. The macronucleus is 140 µm long and 12 µm wide on average ( Table 1). It displays a somewhat looser appearance in the squat forms. Staining with DAPI reveals a transverse periodicity along the macronucleus of each form suggesting alternation of zones differing in chromatin compaction. In each form the macronucleus occupies an axial position and extends from one end to the other end of the ciliate. The macronucleus is flanked on one side with a median micronucleus that is ovoid or spherical in shape (7 µm in diameter; average value), and on the other side with a longitudinal row of two to nine pulsatile vacuoles.

Kin: Kineties; Kin df: Kineties of dorsal face; Kin vf: Kineties of ventral face; Ma: Macronucleus; Max: maximum; Mi: Micronucleus; Min: minimum; Mi Diam: Micronucleus diameter; Pv: Pulsatile vacuoles; SD: Standard Deviation; SF: Skeletal Fibers; µm: micrometer; N=30

Ciliature. Ciliature topography is regular with an average of 85 meridional kineties homogenously covering the whole cell body ( Figure 3 ). Kineties from each side are separated by two laterals secant systems. These intersecting systems are not marked in the squat forms, but are well developed in elongated forms. A subset of adjacent kineties become folded at a distance below the skeletal apparatus the formingone (elongated forms) or two (stocky forms) sets of grooves in theanterior half and, sometimes, a series at the posterior two thirds of the cell ( Figures 3A and 3B ).

Skeletal apparatus. The skeletal apparatus is located in an apical depression of the cell body. ( Figures 3A and 3B ). In the elongated forms, it comprises V-shaped element whose extended branches widen in the transversal plan to the main axis of the cell. The two branches of the V-shaped element are unequal; the left branch is longer and more slender than the right branch ( Figure 3D ).These branches unite in a thickened top forming the salient part of the V-shaped element. Twenty fife skeletal fibres (average value) arise from the branches. These fibers extend on a short distance toward the posterior pole of the ciliate. Importantly, the skeletal fibres project from each of the branches. From the left arm, we can observe 6 to 11 thin and short fibres. In the squat forms, the structure of the skeletal apparatus is comparable to that of the elongated forms.

Diagnosis. Commensal of the digestive tract of Alma nilotica and Alma emini . Shape cylindroid, 140–247 x 40 –98 µm. A single row of 2 to 9 pulsatile vacuoles. 40–44 kineties on each side of the cell. The skeletal apparatus comprises 23–28 skeletal fibers which project from the two branches of a V-shaped element.

Type host: Foregut and midgut, in earthworms ( Alma nilotica and Alma emini ).

Type locality: Ebebda (4°00’– 4°30’N; 11°30’– 11°50’E) and Nkolbikogo (3°65–4°N; 11°30’–11°70’E), Center region, Cameroon.

Etymology: The species is named " polymorphus " in reference to the diversity of cellular shapes.

Type material: Slides of the holotype (MNHN-IR-2017-0001) are deposited to the protist collection of the National Museum of Natural History , Paris, France.

Deposited date: February 2017.

Figures

FIGURE 2. Hoplitophrya polymorphus sp. nov. A–C. elongated form (drawing after silver staining); B–C. elongated forms. B. double staining by DAPI (blue) and immunofluorescence microscopy (IF) using FITC-conjugated anti-tubulin antibody (green); C. DAPI staining and bright field microscopy merge; D. stocky form (drawing after silver staining); E. stocky form stained by DAPI and FITC-conjugated anti-tubulin antibody (green); F. Bright field microscopy of a silver stained stocky form; Ma. macronucleus; Mi. micronucleus; Sb. skeletal branch; Sf. skeletal fibres; Vp. pulsatile vacuoles. Scale bar: 20 µm.

FIGURE 3. Hoplitophrya polymorphus sp. nov. A. ciliature of the ventral face with the skeletal apparatus in elongated form; B. ciliature of the ventral face in stocky form; C. ciliature of the dorsal face of elongated form; D. details of the skeletal apparatus; Fk. folding of kineties; Sl. suture line; Ss. Secant system. Scale bar: 20 µm.