Chilodontopsis depressa (Perty, 1852) Blochmann, 1895

Omar, Atef & Jung, Ji Hye Choi and Jae-Ho, 2023, New record of ten ciliate species (Protozoa, Ciliophora) from South Korea, Journal of Species Research 12 (1), pp. 95-108 : 99-101

5. Chilodontopsis depressa (Perty, 1852) Blochmann ,

1895 ( Fig. 5 )

Material examined. Water sample from a temporary puddle from Baugil , Gangneung-Wonju National University , Jibyeon-dong , Gangneung-si, Gangwon-do, Korea (37°46 ʹ 30.30 ʺ N, 128°51 ʹ 46 ʺ E) on May 18, 2021 .

Diagnosis. Size about 100 × 45 μm in vivo and 65 - 80 × 25 - 30 μm after protargol impregnation (n = 7); body ellipsoidal, length:width ratio about 3: 1, dorsoventrally flattened; cortex studded with cortical granules between ciliary rows both in vivo and after protargol impregnation; macronucleus in mid-body and sometimes in posterior third of body, globular about 15 μm in diameter; contractile vacuole very large in posterior ventral portion of body; cyrtos in anterior third of body and consists of about 14 nematodesmal rods; synhymenium running obliquely on ventral side, composed of about 30 dikinetids; 30 - 40 somatic ciliary rows.

Distribution. Austria, Brazil, Chile, Germany, South Korea.

Remarks. The Korean population of Chilodontopsis depressa agrees with the description of Foissner et al. (1994) in almost all features. Up to date, 11 species are assigned to the genus Chilodontopsis , only five of them with known morphology ( Wang et al., 2012), i.e., C. Depressa ; C. kurensis Alekperov, 1985 ; C. muscorum Kahl, 1931 ; C. simplex Ozaki and Yagiu, 1941 ; and C. vermiformis Deroux, 1978 ( Kahl, 1931; Ozaki and Yagiu, 1941; Deroux, 1978; Alekperov, 1985). Chilodontopsis depressa is most similar to C. muscorum but they differ mainly in the body shape (ellipsoidal vs. oval), the size of macronucleus (~15 μm vs. 10 × 5 μm), and the number of somatic kineties (30 - 40 vs. ~21) ( Foissner, 1984). Also, C. depressa differs from C. simplex , which was described in details by Wang et al. (2012), in the smaller body size (65 - 80 × 25 - 30 μm vs. 90 - 160 × 45 - 95 μm), the body shape (ellipdoidal vs. oval), the smaller macronucleus (15 × 15 μm vs. 25 - 55 × 20 - 40 μm), the lower number of somatic kineties (30 - 40 vs. 59 - 78), and the dikinetids in the synhymenium (~30 vs. 45 - 90) ( Wang et al., 2012).

Voucher slides. One slide with protargol-impregnated specimens was deposited at National Institute of Biological Resources, Korea (NIBRPR0000111063).

Figures

Fig. 5. Chilodontopsis depressa in life (A-D) and after protargol impregnation (E-G). A-D, Ventral (A, B) and dorsal (C, D) views, showing the body shape, the cyrtos in anterior body half, the macronucleus in mid-body, the cortical granules, and the oblique synhymenium (arrows). E, F, Ventral views showing the body shape, the nuclear apparatus either in mid-body or in posterior third of body.Arrows denote the synhymenium. Note the cortex is covered with impregnated cortical granules between somatic kineties. G, Ventral view showing the cyrtos, which consists of about 14 nematodesmal rods. Arrows indicate the synhymenium. CG, cortical granules; CV, contractile vacuole; CY, cytopyge; MA, macronucleus; N, nematodesmal rods. Scale bars 20μm.