Clevelandella elongata ( 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 : 27-30

Clevelandella elongata ( Kidder, 1937)

( Figs 25–27 ; Supporting Information, Table S34)

Clevelandella elongata was detected and morphologically characterized in one population (SRU). When present, C. elongata was moderately abundant (20–30 cells per host) with the other ciliate species being more abundant.

Description based on SRU population:

Largest member of Clevelandellidae (on average 285 × 54 µm in vivo, range 245–321 × 43–71 µm; on average 220 × 61 µm in protargol preparations, range 184–259 × 43–75 µm). Elongated, almost vermiform in vivo, slightly dorsoventrally flattened, anterior end bluntly pointed, posterior end truncate and slightly flared, ventral margin convex, dorsal margin concave ( Figs 25C , 27C). Cells shrink asymmetrically in protargol preparations (see Supporting Information, Table S50) and long axis straightens compared with more sinuous living specimens. Peristomial projection merges gradually with body proper hampering precise length measurement but, on average 20% of cell length (range 14–23%). Macronucleus broadly lenticular, situated slightly obliquely in anterior half of cell, large relative to cell (on average 51 × 24 µm), karyophore at anterior and posterior ends of macronucleus, usually distinct in vivo and in protargol preparations but sometimes indiscernible. Micronucleus large, globular (on average 7 µm diameter), adjacent to anterior end of macronucleus. Somatic cilia arranged in very closely spaced kineties, somatic cilia limited to approximately anterior 50% of cell, usually a short ‘tail’ of ciliated cortex extends posteriorly ( Fig. 27A , B, D). Right sutural kinetofragments absent. Circumperistomial kineties very densely ciliated ( Fig. 27A , B, D, E). Adoral zone extends about 45% of cell length on average, composed of an average of 94 membranelles (range 75–120). POM diplostichomonad only in anterior quarter ( Fig. 26A , E).

Remarks: Individuals of our population were longer and distinctly more slender in vivo than indicated by Kidder’s diagnosis for the species. Kidder (1937) did not specify whether his diagnosis for C. elongata was based on measurements from in vivo observations or fixed material, although the latter possibility seems most plausible given the technology available at that time.

Figures

Figure 25. Clevelandella elongata in vivo. From SRU.A, ventral view showing adoral membranelles (black arrow), cytostome (white arrow), contractile vacuole (white arrowhead), and hyaline subcortical layer (black arrowheads). B, left ventrolateral view (optical section) showing micronucleus (white arrow), karyophore (black arrows), contractile vacuole (white arrowhead), and posterior extent of ciliation (black arrowheads). C, left ventrolateral view showing micronucleus (white arrow), karyophore (black arrow), and cilia of the circumperistomial kineties (white arrowheads). D, detail of same cell as (C) showing peristomial overture (black arrowhead) and cilia of adoral membranelles (white arrow). Ma, macronucleus. Scale 20 µm.

Figure 26. Clevelandella elongata after protargol impregnation. From SRU. A, ventral view (optical section) showing micronucleus (white arrow), anterior part of the karyophore (black arrow), and paroral membrane (black arrowhead).B–E, the same cell in ventral view: B, (optical section) showing anterior part of karyophore (black arrow), micronucleus (white arrowhead), adoral membranelles (white arrow), and paroral membrane (black arrowhead); C, ventral infraciliature showing right kinetal suture (black arrowhead), left-hand spiralling ventral kineties (asterisk), and kineties converging to form ciliary whorl on inconspicuous left protuberance (white arrowhead); D, dorsal infraciliature showing straight course of dorsal kineties (asterisk) and looping kineties of peristomial projection (black arrowhead); E, detail view of the long file (black arrowhead) and short file (white arrowhead) of the paroral membrane. F, detail showing anterior (black arrowhead) and posterior (white arrowhead) parts of the karyophore and the micronucleus (white arrow). Ma, macronucleus. Scale bars: 20 µm.

Figure 27. Clevelandella elongata in the scanning electron microscope. From SRU.A, right ventrolateral view showing metachronal ciliary waves (white arrows), and ‘tail’ of ciliated basal bodies extending posteriorly on right ventrolateral surface (white arrowhead) near the right suture (white asterisk). Cilia of the adoral membranelles protrude from the buccal overture (black arrow). Cilia of the collecting chamber protrude from the cytoproct (black arrowhead). B, dorsal view showing ‘tail’ of ciliated basal bodies extending posteriorly on right ventrolateral surface (black arrowhead) and cilia of circumperistomial kineties (white arrowhead). C, left dorsolateral view showing the cytoproct (black arrowhead), dorsal kineties (black asterisk), proximal margin of buccal overture (white arrow), cilia of the adoral membranelles (black arrow), and circumperistomial kineties (white arrowhead). D, right dorsolateral view showing posteriorly extending ‘tail’ of cilia (black arrowhead), right suture between dorsal kineties (white asterisk) and ventral kineties (black asterisk), and densely ciliated circumperistomial kineties (white arrow). E, dorsal view showing straight dorsal kineties (white asterisk), the ciliary ‘tail’ (black arrowhead), and cilia of circumperistomial kineties (white arrow). F, posterodorsal view showing convexity of the right dorsolateral cell surface (white asterisk), cilia of circumperistomial kineties (white arrowhead), and cilia of adoral membranelles (black arrow). G, left lateral detail view showing proximal margin of buccal overture (white arrow), circumperistomial cilia (black arrow), adoral membranelles (black arrowheads), and paroral membrane (white arrowheads).H, posterolateral detail view of the buccal overture showing posteriormost adoral membranelle (white arrow), circumperistomial cilia (black arrow), right suture (white arrowhead) between ventral kineties (black asterisk) and dorsal kineties (white asterisk). I, posterior view of buccal overture showing adoral membranelles (black arrowhead), paroral membrane (white arrowhead), and circumperistomial cilia (white arrow). Scale bars: 50 µm (A–E), 20 µm (F–I).