Tetmemena indica Bharti et al., 2019

Omar, Atef & Jung, Jae-Ho, 2024, Disentangling the stylonychine ciliates (Ciliophora: Hypotricha): the establishment of two new genera using an integrative taxonomic approach, Zoological Journal of the Linnean Society (zlae 144) 202, pp. 1-40 : 24-27

Tetmemena indica Bharti et al., 2019

( Figs 13–15 ; Table 1 )

2019 Tetmemena pustulata indica nov. subspec. — Bharti, Kumar, La Terza and Chandra, Eur. J. Protistol. 71:2 (original description; the holotype and paratype specimens were deposited at the Zoological Survey of India, Kolkata, India).

2023 Tetmemena indica nov. stat. —Omar, Jang and Jung, Front. Microbiol. 14:1159634 (raised to species level based on data from original description, no voucher material available).

Voucher material: Two voucher slides (NNIBRPR27180 and NNIBRPR27181) of the Korean population described below with protargol-impregnated specimens have been deposited in the Nakdonggang National Institute of Biological Resources, Korea.

Morphological description of the Korean population: Size ~70–100 μm × 30–40 μm in vivo (N = 5) and 50–68 μm × 20–28 μm after protargol impregnation. Body ellipsoid; anterior end narrowly rounded and truncated to left; posterior end rounded, usually with distinct emargination at right after protargol impregnation; body margins parallel and straight, sometimes only slightly convex or concave. Length:width ratio 1.8–2.4:1, on average 2.1:1 ( Figs 13A–C , 14A–C ). Nuclear apparatus commences at ~19% of body length and ends at ~77%. Invariably two macronuclear nodules and two micronuclei. Individual macronuclear nodules ellipsoidal, usually with irregular outline in protargol-impregnated specimens, in or slightly left to midline of the body, 11–20 μm × 5–8 μm after protargol impregnation. Micronuclei usually attached to macronuclear nodules, spherical, ~5 μm across ( Figs 13C , 14B, C ). Contractile vacuole in mid-body near left cell margin; at end of diastole ~8 μm across. Collecting canals not observed. Cortex rigid and colourless; cortical granules lacking. Cytoplasm hyaline, with few lipid droplets, refractive crystals throughout cell and especially in posterior portion of cell, and food vacuoles 10–13 μm across containing bacteria and small flagellates ( Figs 13A , 14A ). Cells usually crawl on the bottom of the culture dish.

Cirral pattern of Tetmemena indica usually in Tetmemena pattern, i.e. 18 FVT cirri arranged as follows: three enlarged frontal cirri, with cilia ~15 μm in vivo; one buccal cirrus; four frontoventral cirri arranged in V-shaped pattern; three postoral cirri in inverted L-shape pattern, cirrus IV/2 placed more anteriorly than cirrus V/4; two obliquely arranged pretransverse cirri; and five transverse cirri arranged in one group forming V-shaped pattern; all cirri project from posterior body end, fringed distally, ~20 μm long in vivo ( Figs 13A, B , 14A, B ). Marginal cirri fine and of same length, ~13 μm long. Right marginal row commences subapically at ~10% of body length and ends posteriorly near body end, composed of 17–21 cirri. Left marginal row commences at ~45% of body length and ends near body end, composed of 11–15 cirri. Gap between posterior ends of marginal rows wide and directed posteriorly ( Figs 13A, B , 14A, B ).

Six dorsal kineties, including two dorsomarginal ones. Kinety 1 shortened anteriorly, possessing 16–20 bristles; kineties 2 and 3 bipolar, not curved anteriorly, possessing 13–17 and 11–14 dikinetids, respectively; kinety 4 distinctly shortened anteriorly, i.e. distinctly shorter than kinety 3 anteriorly and possessing 8–14 dikinetids. Dorsomarginal kineties 1 and 2 extend posteriorly over about two-fifths and one-quarter of cell length and possess 5–9 and 2–5 dikinetids, respectively. Three moderately widely spaced caudal cirri, ~25 μm long in vivo, one each at end of kineties 1, 2, and 4 ( Figs 13C , 14C ).

Adoral zone occupies 41–54% of body length and is composed of 25–28 membranelles. Distal end of adoral zone at an average of 7% of body length (DE-value 0.15 on average). Cilia of membranelles ~20 μm long in vivo, bases of largest membranelles ~4 μm wide after protargol impregnation. Buccal cavity, i.e. the transverse distance between anterior end of paroral membrane and the opposite adoral membranelle on left side, 4–7 μm wide and narrowing posteriorly ( Figs 13A, B , 14A, B ). Undulating membranes in Stylonychia pattern. Paroral membrane commences at the same level as buccal cirrus, ~21% of body length, with a length of ~11 μm in protargol-impregnated specimens. Endoral membrane commences slightly posterior to anterior end of paroral membrane at ~23% of body length, with a length of ~12 μm after protargol impregnation, and extends to buccal vertex. Pharyngeal fibres extend transversely to right body margin ( Figs 13A, B , 14B ).

Morphogenesis: The ontogenesis of Tetmemena indica is identical to that of T. polymorpha Omar et al., 2023 in all respects ( Fig. 15A–F ).

Figures

Figure 13. Tetmemena indica from life (A) and after protargol impregnation (B, C). A, ventral view of a representative specimen showing the elliptical body, the transverse cirri arranged in one group, and the emargination in the right posterior body end. B, C, ventral (B) and dorsal (C) views of a voucher specimen showing the body shape, the undulating membranes in Stylonychia pattern, the transverse cirri in one group, the infraciliature, and the nuclear apparatus.Abbreviations:1–4, dorsal kineties; AZM, adoral zone of membranelles; BC, buccal cirrus; CC, caudal cirri; DM1, DM2, dorsomarginal kineties; EM, endoral membrane; FC, frontal cirri; FVC, frontoventral cirri; LMR, left marginal row; MA, macronuclear nodules; MI, micronuclei; PF, pharyngeal fibres; PM, paroral membrane; PTVC, pretransverse cirri; PVC, postoral cirri; RMR, right marginal row; TC, transverse cirri. Scale bars: 30 μm in A; 20 μm in B, C.

Figure 14.Tetmemena indica from life under differential interference contrast microscopy (A) and after protargol impregnation (B, C). A, ventral view showing the elliptical body and the emargination in right posterior body end. B, C, ventral (B) and dorsal (C) views of a voucher specimen showing the body shape, the undulating membranes, the transverse cirri in two distinctly separated groups, the infraciliature, and the nuclear apparatus.Abbreviations:1–4, dorsal kineties; AZM, adoral zone of membranelles; BC, buccal cirrus; CC, caudal cirri; DM1, DM2, dorsomarginal kineties; FC, frontal cirri; FVC, frontoventral cirri; LMR, left marginal row; MA, macronuclear nodules; MI, micronuclei; PM, paroral membrane; PTVC, pretransverse cirri; PVC, postoral cirri; RMR, right marginal row; TC, transverse cirri. Scale bars:30 μm.

Figure 15. Tetmemena indica after protargol impregnation. A, B, ventral views of early dividers showing the origin of anlagen IV–VI of the proter from cirrus IV/3 and the origin of anlagen V and VI of the opisthe from cirrus V/4. C, D, ventral (C) and dorsal (D) views of an early divider, showing the formation of the cirral anlagen and the intrakinetal origin of the dorsal anlagen. E, F, ventral (E) and dorsal (F) views of a late divider, showing the differentiation of cirri, the fragmentation of dorsal kinety 3, the formation of a single macronucleus, and the new caudal cirri formation. Arrowheads mark the marginal anlagen. Abbreviations: 1A–4A, dorsal kineties’ anlagen; CC, caudal cirri; DM1, DM2, dorsomarginal kineties; I–VI, frontal–ventral–transverse anlagen; OP, oral primordium. MA, macronuclear nodules; MI, micronuclei.Scale bars:20 μm.