Notohymena australis Foissner

Yang, Caiting, Liu, An, Xu, Yusen, Xu, Yuan, Fan, Xinpeng, Al-Farraj, Saleh A., Ni, Bing & Gu, Fukang, 2015, Phylogenetic positions of four hypotrichous ciliates (Protista, Ciliophora) based on SSU rRNA gene, with notes on their morphological characters, Zootaxa 4000 (4), pp. 451-463 : 457

Notohymena australis Foissner & O’ Donoghue, 1990

( Figure 3 A–G; Table 1)

This species was well described by original report, thus only brief redescription based on new populations was supplied.

Morphological description of Chinese population: Body 110-130 × 30-50 µm, long elliptical in outline, with length: width ratio approximately 4: 1 in vivo ( Fig. 3 A, B). Body flexible but not contractile. Cortical granules yellow or orange, spherical, about 0.4 µm across ( Fig. 3 C, D), and they arranged mainly along cirral rows and dorsal kineties ( Fig. 3 B, C, E). Buccal field about 46% of body length ( Fig. 3 F). Bases of largest membranes in life about 10 µm. Two ellipsoidal macronuclear nodules, 15–33 × 8–11 µm in size. One contractile vacuole about 20 µm across, located left of cell mid-line, slightly in front of mid-body. Cytoplasm usually containing small lipid droplets with size about 1–7 µm in diameter ( Fig. 3 A, B). Locomotion by swimming rotating about its longitudinal axis moderately fast or relatively slow crawling on bottom of Petri dishes or on debris.

Paroral bends to left and has a hooked distal ( Fig. 3 F, G). Cirri on ventral side arranged in typical 8: 5: 5 pattern. Frontal cirri is about 12–15 µm long in life, transverse cirri, about 18 µm. Two marginal rows converging posterior ( Fig. 3 G). Six dorsal kineties, cilia about 5 µm long; leftmost 3 (dorsal kineties 1, 2, and 3) of body length; fourth and fifth dorsal kineties terminate below the mid-body respectively; rightmost dorsal kinety (dorsal kinety 6), very short, only composed of 2–5 dikinetids. 7–10 caudal cirri located at posterior body margin and arranged in three rows, located at the posterior end of dorsal kineties 1, 2, and 4 respectively ( Fig. 3 G).

Remarks: This species was recorded successively from Australia, Bavaria, Korea and Japan. Our population corresponds well with previous reports (Foissner & O’ Donoghue, 1990; Choon & Shin, 2010; Hu & Yasushi, 2015) in terms of cyst, locomotion, cortical granules and marginal cirri, and differs from them in larger adoral zone about 46% (vs. 38% in Australian population, 36% in Korean population, 37% in Japanese population) and bases of largest membranes in life about 10 µm (vs. 7 µm in Australian population, 8 µm in Japanese population).

Figures

FIGURE 3. Notohymena australis from life (A – E) and after staining with protargol (F, G). A, B. Ventral (A) and dorsal (B) view of typical individual, showing the cortical granules that arranged in rows on dorsal side (arrowheads in B). C, E. Details of cortical granules on dorsal side, showing the different clusters (arrowheads). D. Lateral view of cortical granules (arrowheads). F. Anterior part of ventral infraciliature, arrowhead depicts the curve at the anterior end of paroral membrane. G. Ventral view of infraciliature, arrowhead refers to the multiple caudal cirri. Scale bars = 40 Μm.