Cyrtohymena (Cyrtohymenides) australis Foissner, 2004

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 : 458

Cyrtohymena (Cyrtohymenides) australis Foissner, 2004

( Figure 4 A–G; Table 1)

Foissner (1995) reported the two populations from Peru (the type) and Costa Rica respectively. The living morphology and infraciliature are fairly clear, thus, only brief redescription was documented here.

Morphological description of Chinese population: Cells in vivo 240-300 × 90-130 µm, very flexible ( Fig. 4 A, B). Buccal area occupying 37% of body length. Cortical granules yellowish to green in color, about 1 µm across, present on both sides, arranged in groups near ventral cirri and dorsal kineties, also scattering irregularly in other parts of pellicle ( Fig. 4 C). Contractile vacuole located near left margin and in anterior 1/2 of body, about 30 µm when fully extended. Two macronuclei each about 36 × 20 µm in vivo. Cyst about 75 µm in diameter, spherical, with smooth surface ( Fig. 4 D).

Typically 8: 5: 5 ventral cirri arrangement, but six transverse cirri present in single specimen examined. Transverse cirri about 45 µm long, extending slightly beyond posterior body end ( Fig. 4 F). Marginal cilia about 20 µm long in vivo. 7–12 dorsal kineties arranged irregularly. A morphogenetic cell of late stage was found and showing four dorsal marginal and three dorsal primordia ( Fig. 4 E, F, G). Always three caudal cirri.

Remarks: Chinese population corresponds well with two previous populations ( Foissner 1995) in terms of living morphology and infraciliature, thus, the identification was acceptable. Foissner (2004) established the subgenus Cyrtohymenides to include cyrtohymenids with larger body size and more than three dorsomarginal kineties, up to now, including C. (C.) aspoecki , C. (C.) australis , and C. (C.) shii . Singh et al. (2013) improved the diagnosis to include more characteristic features, i. e., slightly large number of frontal-ventral-transverse cirri, marginal rows not confluent posteriorly, and multiple fragmentation of the third dorsal kinety during ontogenesis. Though, Cyrtohymena australis Foissner, 1995 was transferred to the subgenus by Foissner (2004), the multiple fragmentation of dorsal kinety 3 is still unconfirmed for the reason of unavailability of the complete ontogenesis process of this species.

Figures

FIGURE 4. Cyrtohymena (Cyrtohymenides) australis from life (A – D) and after staining with protargol (E – G). A, B. Two typical individuals, showing the body shape and colour. C. Cortical granules on dorsal side, arrows mark the cortical granules that scattered in pellicle. D. Cyst. E. The three anlagen for dorsal kineties of proter (arrowheads). F, G. Four dorsomarginal anlagen of proter (arrowhead, F) and opisthe (arrowhead, G) in the same specimen as in E. Scale bars = 100 Μm (A, B), 30 Μm (D).