Apostylonychia notophorides Omar & Jung 2024, comb. nov.
Creators: name: Omar, Atef
name: Jung, Jae-Ho
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Chromista
Ciliophora
Hypotrichea
Oxytrichida
Oxytrichidae
Apostylonychia
Apostylonychia notophorides

description: Apostylonychia notophorides (Foissner, 2016) comb. nov.
(Figs 5–9; Table 1)
2016 Stylonychia notophorides nov. spec. – Foissner (2016), Denisia 35:835, figs 283, 284 (original description).
Improved diagnosis (based on original description and our data): Body size 70–120 μm × 28–50 μm in vivo and 64–91 μm × 27–45 μm after protargol impregnation. Body obovate, widest at mid of adoral zone; length:width ratio 1.9–2.9:1. Two separate macronuclear nodules. Right marginal row composed of 9–16 cirri, left row of 9–12 cirri. Dorsal kinety 4 commences at the same level as kinety 3 or slightly shorter. Adoral zone occupies 42%–57% of body length after protargol impregnation and is composed of 24–32 membranelles. Resting cysts ~45 μm in vivo, with spines 4–7 μm wide at base and 5–10 μm long and fused macronuclear nodules.
Voucher material: Two voucher slides (NNIBRPR27178 and NNIBRPR27179) with protargol-impregnated specimens have been deposited in the Nakdonggang National Institute of Biological Resources, Korea. Two further voucher slides (GUC009426 and GUC009427) have been deposited in the Jung laboratory (J.-H. Jung) in Gangneung-Wonju National University.
Morphological description of the Korean population: Size 90–120 μm × 35–50 μm in vivo (usually ~110 μm × 45 μm, N = 14) and 64–91 μm × 27–45 μm after protargol impregnation. Body moderately obovate, widest in mid of adoral zone of membranelles, wide frontal area, scutum hyaline, rounded and slightly narrowed anteriorly, obliquely truncated to left, body margins gradually converging posteriorly, both right and left margin straight or slightly convex. Length:width ratio 1.9–2.6:1, on average 2.2:1 (Figs 5A–C, 6A–F, 7A–E). Nuclear apparatus commences at ~23% of body length and ends at ~72%. Invariably two macronuclear nodules and two micronuclei; cells with a single micronucleus observed only during division. Individual macronuclear nodules broadly ellipsoidal, in or slightly left of the midline of the body, in vivo 15–25 μm × 10–15 μm. Micronuclei usually attached to macronuclear nodules, spherical, ~4 μm across (Figs 5C, 6F, 7A, B). Contractile vacuole in mid-body at left cell margin; at end of diastole ~14 μm across. Collecting canals not recognizable (Figs 5A, 6E, F). Cortex rigid and colourless; cortical granules lacking. Cytoplasm hyaline, studded with lipid droplets, refractive crystals in posterior portion of cell, and food vacuoles ≤8 μm across containing bacteria, yeast, and occasionally ≤15 μm across containing flagellates and starch grains (Figs 5A, 6A–H). Usually crawling slowly on bottom of culture dish or swimming by spiralling around long body axis.
Cirral pattern of Apostylonychia notophorides usually in Stylonychia mytilus pattern, i.e. 18 FVT cirri arranged as follows: three enlarged frontal cirri distinctly shifted to right, i.e. right of the midline of the body, with cilia ~26 μm in vivo; one buccal cirrus with cilia ~21 μm in vivo; four frontoventral cirri arranged in V-shaped pattern with cilia 18 μm long in vivo; three postoral cirri in inverted L-shape pattern, with same length as frontoventral cirri, cirrus IV/2 placed more anteriorly than cirrus V/4; two obliquely arranged pretransverse cirri, with cilia ~20 μm long; and five transverse cirri arranged in two groups, two right and three left, subterminal, all cirri project from posterior body end, fringed distally, ~30 μm long in vivo (Figs 5A, B, 6A, B, G, 7A, C, D, F). Marginal cirri fine and of same length, ~18–20 μm long. Right marginal row commences subapically at ~14% of body length and ends posteriorly at ~94% of body length, composed of 10–15 cirri. Left marginal row commences at ~47% of body length and ends at ~98% of body length, composed of 9–12 cirri. Gap between posterior ends of marginal rows slightly shifted to the right (Figs 5B, 6B, 7A, C, D).
Six dorsal kineties, including two dorsomarginal ones, with bristles ~4 μm long in vivo. Kineties 1–3 bipolar, not curved anteriorly, possessing 22–26, 17–21, and 14–18 dikinetids, respectively; kinety 1 slightly shortened anteriorly, i.e. usually ~5 μm shorter than kineties 2 and 3 after protargol impregnation; kinety 4 slightly shortened anteriorly, i.e. ~7 μm shorter than kineties 2 and 3 anteriorly and possesses 10–16 dikinetids. Dorsomarginal kineties 1 and 2 extend posteriorly over about half and first quarter of cell length and possess 6–10 and 3–6 dikinetids, respectively. Three caudal cirri, ~35 μm long in vivo, slightly shifted to the right, one each at end of kineties 1, 2, and 4; left caudal cirrus usually straight or beating slower than the other two cirri (Figs 5C, 6E, H, 7B, E, G, H).
Adoral zone occupies 49%–57% of body length and is composed of 29–32 membranelles. Distal end of adoral zone commences at an average of 10% of body length on right side (DE-value 0.19 on average). Cilia of membranelles ~20 μm long in vivo, bases of largest membranelles ~5 μm wide after protargol impregnation (Figs 5A, 6A–D, 7A, C, D). Buccal cavity, i.e. the transverse distance between anterior end of paroral membrane and the opposite adoral membranelle on the left side, 11–16 μm wide and narrowing posteriorly. Undulating membranes at the midline of the body, cilia 9–10 μm long, in Stylonychia pattern, i.e. parallel or slightly overlapping. Paroral membrane commences anterior to buccal cirrus at ~22% of body length, with a length of ~16 μm in protargol-impregnated specimens, and extends to near end of buccal vertex. Endoral membrane commences posterior to anterior end of paroral at ~26% of body length, with a length of ~16 μm after protargol impregnation, and extends to end of buccal vertex. Pharyngeal fibres extend transversely to right body margin (Figs 5A, B, 6A, B, 7A).
Resting cysts: Cysts of Apostylonychia notophorides spherical, size including spines ~45 μm across in vivo. Wall hyaline, ~3–4 μm thick in vivo, ornamented by thick spines, 4–7 μm wide at base and each 5–10 μm long. Cytoplasm studded with lipid droplets; macronuclear nodules fuse to form a single macronuclear nodule in mature cysts (Figs 6I, J, 7I, J).
Morphogenesis: Apostylonychia notophorides divides in the same ontogenetic pattern as Apostylonychia baugilensis in all respects (Figs 8A–H, 9A–D).
description: Published as part of Omar, Atef & Jung, Jae-Ho, 2024, Disentangling the stylonychine ciliates (Ciliophora: Hypotricha): the establishment of two new genera using an integrative taxonomic approach, pp. 1-40 in Zoological Journal of the Linnean Society (zlae 144) (zlae 144) 202 on pages 15-16, DOI: 10.1093/zoolinnean/zlae144, http://zenodo.org/record/14764525