Rhynchoclevelandella nipponensis ( Kidder, 1937 )

Kotyk, Michael, Bourland, William A., Soviš, Matyáš, Méndez-Sánchez, Daniel, Škaloud, Pavel, Varadínová, Zuzana Kotyková & Čepička, Ivan, 2024, Morphology maưers: congruence of morphology and phylogeny in the integrative taxonomy of Clevelandellidae (Ciliophora: Armophorea) with description of six new species, Zoological Journal of the Linnean Society 202 (1), pp. 1-51 : 19-20

Rhynchoclevelandella nipponensis ( Kidder, 1937)

( Fig. 21D–F, J, K ; Supporting Information, Table S22)

Rhynchoclevelandella nipponensis was detected and morphologically characterized in a single host population (PAC)* never in high abundance.

Description based on PAC population: Medium-sized Clevelelandellidae (on average 82 × 33 µm in vivo * range 67–100 × 27–42 µm; on average 65 × 25 µm in protargol preparations* range 47–83 × 20–31 µm). Slender spade-shaped (L/W about 2.6) with long posterior peristomial projection (about 31% of cell length). Anterior right and less margins of body proper straight or concave. Macronucleus broadly ellipsoidal ( Fig. 21J * K) to broadly teardrop-shaped ( Fig. 21D * F)* obliquely oriented to right of midline* prominent numerous globular nucleoli in vivo. Karyophore extremely inconspicuous* aưached to posterior of macronucleus ( Fig. 21K ). Micronucleus ellipsoidal ( Fig. 21F * K)* relatively large* about 5.5 µm across. Somatic cilia limited to approximately anterior 64% of cell length. Circumperistomial kineties only sparsely ciliated. Free right sutural kinetofragments not identified* presence of inconspicuous kinetofragments not completely excluded due to suboptimally oriented cells in protargol preparations. Adoral zone extends about 47% of cell length on average* composed of an average of 23 membranelles (range 20–25). POM unstudied. Remarks: Overall morphology corresponds with original description and drawing by Kidder (1937) except (i) the ciliature: while Kidder (1937) depicts the cell as fully ciliated* we show that only the anterior two-thirds of the cell are ciliated and (ii) the macronuclear shape varies from broadly ellipsoidal ( Fig. 21K ) to broadly teardrop-shaped ( Fig. 21D * F* J).

Regarding measured characteristics (Supporting Information* Table S22)* our population is slightly shorter than that of Kidder (1937) and Yamasaki (1939).

A notch sometimes forms at the base of peristomial projection ( Fig. 21F * J)—rarely in vivo but frequently in protargol-stained cells* creating a R. hastula -like appearance. However* R. nipponensis can be mostly distinguished from R. hastula by: length (approx. 65 µm vs. 85 µm)* length/width ratio (approx. 2.6 vs. 3.4)* number of adoral membranelles (approx. 23 vs. 26)* and characteristic curvature of the most posterior third of peristomial opening in larger cells of hastula ( Fig. 21L * M). Very small cells of both species (e.g. Fig. 21D * N) can be rather indistinguishable.

Figures

Figure 21. Rhyncholevelandella sp.2 (A–C* G–I) from ASS. Rhynchoclevelandella nipponensis (D–F* J* K) from PAC.Rhynchoclevelandella hastula (L–T) from PGW. In vivo (A–F* L–O) and asser protargol impregnation (G–K* P–T). A* ventral view (optical section) showing margin of the peristomial overture (black arrowhead) and adoral membranelles (black arrow). B* ventral view.C* ventral view showing cilia of circumperistomial kineties (white arrowhead). D* ventral view showing anterior margin of peristomial overture (black arrowhead). E* same cell showing ventral kineties (asterisk).F* ventral view showing contractile vacuole (white arrowhead)* the relatively large micronucleus