Clevelandella hromadkai, Kotyk & Bourland & Soviš & Méndez-Sánchez & Škaloud & Varadínová & Čepička, 2024

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 : 8-10

Clevelandella hromadkai sp.nov.

( Figs 8–11 ; Supporting Information, Tables S7–S10)

Description based on populations from hosts ASS from Papua Neo Guinea and PAC from Vietnam: Medium to very large Clevelandella , widely variable in both size and shape. In ASS population, size in vivo 103–262 × 39–81 µm, usually about 164 × 57 µm; size in protargol preparations 77–164 × 25–66 µm, usually about 117 × 40 µm; in PAC population, size in vivo 127– 339 × 44–85 µm, usually about 190 × 58 µm; size in protargol preparations 110–276 × 31–83 µm, usually about 155 × 45 µm. Body shape usually broadly cultriform, ventral surface of the body proper convex, dorsal surface concave, anterior end of cell bluntly pointed and curved more ( Figs 9E , 10C, E) or less ( Figs 9C , H, 10B, 11A, D, E) in dorsal direction. Peristomial projection flares to merge gradually with body proper, prominence of left lobe varies from less conspicuous ( Figs 9A , B, 10A) to more prominent ( Figs 8A , D, F, 9D, F–H, 10F, 11B, C, E) with a notch formed between the lobe and peristomial projection ( Figs 8F , 9F), in contrast to spade-shaped species, the notch degree between peristomial projection and left lobe seems never to be under 90°; posterior margin of peristomial projection truncate. L/W ratio highly variable in individuals from both hosts, from shorter stouter forms ( Figs 8D–G , 9A–I, 11A–E) to longer more slender cells ( Figs 8A , B, 10A–F). Macronucleus broadly ellipsoidal in short forms ( Figs 8D , E, 9A–F), to narrowly ellipsoidal in long forms ( Fig. 10A–C , E, F). Karyophore inconspicuous; when detectable, attached to posterior end of macronucleus and right body margin ( Figs 8A , B, D, 10A, D). Micronucleus ellipsoidal, usually adjacent to right anterior margin of macronucleus, enclosed in separate membrane ( Figs 8A , B, D, 9A, C, E, F, 10A, C–E). Swims moderately fast while rotating around long axis.

Somatic ciliature composed of about 60–85 somatic ciliary rows in Clevelandellidae pattern; cilia present only on approximately anterior half of cell; about 20–25 ciliary rows on the peristomial projection in ASS population. Ciliary rows in PAC population not counted. Right suture has only two or three small free kinetofragments (not shown).

Peristomial projection occupies an average of 35% of total body length. Lateral part of peristomial opening extends about one-half ( Figs 9B , 11B, D, E) length of peristomial projection in short cells, about one-third ( Fig. 10A , B) length of peristomial projection in long cells. Adoral zone usually extends about 50% of body length, composed of an average of 54 (ASS) to 62 (PAC) membranelles, base of membranelles longest in midportion of peristomial projection. POM as described for the family ( Fig. 9I ).

Remarks on short and long morphotypes: Clevelandella hromadkai shows considerable intraspecific phenotypic variability. The ASS population, while genetically uniform, can be divided in two distinct phenotypes: short ( Figs 8D–G , 9A–I, 11A–F) and long ( Figs 8A , B, 10A–F). In a single host, only one phenotype seems to occur at a given time; from nine thoroughly inspected hosts the short morph occurred in two females and two larvae, the long morph occurred in four males and one larva. Apart from the obvious length difference (mean in vivo 127 µm vs. 215 µm) and other morphological characteristics (e.g. number of adoral membranelles—see Supporting Information, Tables S8, S9), both morphs can be distinguished by their shapes: the short one is stouter (body L/W ratio 2.5) with a more rounded anterior end and the long one is more slender (body L/W ratio 3.7).

Occurrence: Three distinct populations of C. hromadkai were found in the hindguts of three Panesthiinae populations:ASS from Papua New Guinea, PAA from Philippines, and PAC from Vietnam. The ASS population occurred in 63% of host individuals regardless of age and sex. When present, C. hromadkai was less abundant (a few tens of individuals) compared to other ciliate species present in a host. The PAC population occurred in 28% of host individuals. Out of nine infected hosts, one was a large larva and eight were visibly old adult males. Most of the PAC hosts exhibited low occurrence of C. hromadkai (around 10 cells) with other ciliate species being more abundant. The exception was one male that harboured around 50 cells of C. hromadkai . When C. hromadkai was present in PAC hosts, the populations of other ciliates were visibly low compared to PAC host, in which C. hromadkai was absent. The PAA population occurred in only 17% of host individuals. Out of two infected hosts (both adult males), one exhibited a low occurrence of the C. hromadkai with the other ciliate species being more abundant. The other host exhibited high occurrence of C. hromadkai with other ciliates being scarce.

Figures

Figure 8. Schematic drawings of Clevelandella hromadkai sp. nov. from life (A–D) and after protargol impregnation (E–G); long morphotype (A–C), short morphotype (D–G). A, left lateral view. B, right lateral view. C, (I–IV) cell outline in clockwise rotation around long axis. D, ventral view. E, ventral view.F, ventral infraciliature.G, dorsal infraciliature.AZM, adoral zone of membranelles; CPK, cilia of circumperistomial kineties; CV, contractile vacuole; HL, hyaline subcortical layer; K, karyophore; Ma, macronucleus; Mi, micronucleus; POM, paroral membrane; POV, peristomial overture; SK, somatic kineties.Scale bars: 50 µm.

Figure 9. Clevelandella hromadkai sp. nov. short morph: from life (A–C, F–H) and after protargol impregnation (D, E, I). From ASS.A, left ventrolateral view showing micronucleus (white arrow), adoral membranelles (black arrow), and the posterior extent of ciliation on the right (black arrowhead) and left (white arrow head) margins. B, ventral view, (optical section) showing the cytostome (white arrowhead), contractile vacuole (black arrow) and margin of the peristomial overture (black arrowhead).C, left lateral view showing collecting vesicles of the contractile vacuole (white arrowheads), the micronucleus (white arrow) and the margin of the peristomial overture (black arrowhead).D,

Figure 10. Clevelandella hromadkai sp. nov.long morph from life (A–C) and after protargol impregnation (D–F). From ASS (A, E, F), and PAC (B–D). A, ventral view showing micronucleus (white arrow), left protuberance (black arrowhead), and karyophore (black arrow).B, left ventrolateral view showing peristomial overture (white arrow), collecting vesicles of contractile vacuole (white arrowheads), and the posterior extent of ciliation on the left ventrolateral margin (black arrowhead).C, right dorsolateral view showing contractile vacuole collecting vesicles (white arrowheads), the posterior extent of ciliation on the dorsolateral margin (black arrow), the micronucleus (white arrow), and the adoral membranelles (black arrowhead).D, detail showing micronucleus (white arrowhead) and karyophore (white arrow).E, left ventrolateral view showing micronucleus (white arrowhead).F, (same cell as E) showing posterior margin of left protuberance. Ma, macronucleus.Scale bars:20 µm (A–C, E, F), 10 µm (D).

Figure 11. Clevelandella hromadkai sp. nov. (from ASS) in the scanning electron microscope.A, right lateral view showing overall cell shape with concave dorsal margin (white arrowhead) and convex ventral margin (black arrowhead), ciliated anterior parts (black asterisk) and unciliated posterior parts (white asterisk) of somatic kineties, and prominent posterior peristomial projection (black arrow). B, posterodorsal view showing left posterior protuberance (black arrowhead) and peristomial overture (black arrow).C, left lateral view showing dorsoventral flattening, cilia protruding from the cytoproct (black arrowhead) on the left protuberance (white asterisk). D, posterodorsal view (down left) showing spiralling somatic kineties (white asterisk) and peristomial overture (black arrow) and right lateral view (black asterisk).E, posterodorsal view showing the cytoproct on the left protuberance (black arrow), the ciliated circumperistomial kineties (white arrowhead), and the adoral membranelles on the right wall of the infundibulum (black arrowhead). F, detail view of the left protuberance showing unciliated parts of kineties (white arrowheads) converging on the ciliated cytoproct (black arrowhead) and the fully ciliated dikinetids of the anterior body part (black arrow). Scale bars: 20 µm (A–E), 5 µm (F).