Pseudomicrothorax agilis Mermod, 1914

Jung, Jae-Ho & Yeo, Jeong Hyeon, 2020, New record of five ciliate species from temporary ponds on a grass lawn, Journal of Species Research 9 (1), pp. 68-76 : 69

1. Pseudomicrothorax agilis Mermod, 1914

Diagnosis. Body size in vivo about 52 × 36 μm (n = 1), 43-57 × 26-37 μm (on average 50.5 × 32.3 μm) after protargol impregnation; elliptical to oval shape; densely filled with green algae. Longitudinal furrows along somatic kineties; extrusomes arranged along the kineties, spindle shape; anchor-shaped when extruded. Nuclear apparatus composed of a single macronucleus (5.5-8.7 × 5.2- 5.8 μm) and a micronucleus (1.5-1.9 × 1.1-1.7 μm); both nuclei spherical to ellipsoidal; micronucleus attached to macronucleus. Three adoral membranelles obliquely arranged to left of oral opening; 15 or 16 nasse kinetosomes; paroral membrane lacking; about 9 basal bodies of oral primordium at left posterior third of kinety 1, always more faint than somatic kineties. 12 somatic kineties.

Distribution. Europe, USA, India, China, and Korea.

Remarks. The Korean population corresponds with a redescription by Foissner et al. (1994), except for the absence of a paroral membrane (see Fig. 6 . on p. 468). Bussers (1976) also reported the paroral in a trophont of P. agilis using the silver nitrate method; however it disappeared or reduced to a few disordered kinetosomes in an encysted cell. From the additional 12 protargol-impregnated specimens examined to confirm the presence/ absence of the paroral, we did not find the paroral and any cyst wall. Peck (1974) also did not identify this structure from the protargol preparation of P. dubius , but observed using the Chatton-Lwoff technique supporting that this species/genus lacks the paroral which is usually confused with the nasse kinetosomes. Pseudomicrothorax agilis can be distinguished from its congeners by the number of somatic kineties (12 vs. 13 or 14 in P. dubius ) or the body shape (rounded vs. truncated posterior body end in P. foliformis ) ( Foissner et al., 1994).

Voucher slides. Two slides of protargol impregnated specimens were deposited at National Institute of Biological Resources, Korea (NIBRPR0000110175, NIBRPR 0000110176).

Figures

Fig. 6. Meseres corlissi after protargol impregnation.A, B. Ventral (A) and dorsal (B) view showing ciliary pattern, oral apparatus, and nuclear apparatus. C. Dorsal view showing elongated somatic cilia. D. Nuclear apparatus.AM, adoral membranelles; K1, somatic kinety 1; Ma, macronucleus; Mi, micronucleus; PM, paroral membrane; VM, ventral membranelles. Scale bars: 30 μm.