Heterostentor coeruleus Song and Wilbert, 2002

Wilbert, Norbert & Song, Weibo, 2005, New contributions to the marine benthic ciliates from the Antarctic area, including description of seven new species (Protozoa, Ciliophora), Journal of Natural History 39 (13), pp. 935-973 : 952-953

Heterostentor coeruleus Song and Wilbert, 2002

( Figures 7D–H , 14J–N )

The present population resembles the form described previously (Song and Wilbert 2002), so a complete redescription is unnecessary. Only the main features found to vary from the 2002 population are included here.

Description

Body often more slender oval than elongated cylindrical, dorsoventrally only slightly flattened, length to width about 1:2–3 when moving freely, but 1:3–5 when attached to substratum by posterior end of cell and contracting from time to time ( Figure 7F ). Dark blue pigments beneath pellicle arranged in at least two patterns: sparsely distributed between ciliary rows with larger granules or conspicuously densely distributed ( Figure 7G, H ). In anterior cell end (around adoral zone of membranelles), these pigments/granules render the cell dark blue.

Numerous membranelles in adoral zone which, in vivo, appear to be clustered into about 20 groups of membranelles ca 25 M m long and extend forwards ( Figure 7E ).

Figures

Figure 7. (A–C) Condylostoma cf. magnum and (D–H) Heterostentor coeruleus from life (D–F) and after protargol impregnation (A–C, G–H). (A) Ventral view, arrows mark the shortened kineties; (B) dorsal view, arrows mark the macronuclear nodules; (C) anterior portion of ventral view, arrow marks the paroral membrane, arrowhead and double-arrowheads point to the distal and proximal ends of adoral zone of membranelles, respectively; (D) a slightly contracted individual; (E) anterior portion, to show the appearance of the membranelles; (F) diagram of movement while attached to the bottom, arrow indicates the caudal region used as attachment area; (G, H) details of pellicle, arrows mark the pigments (cortical granules). Scale bars: 100 Mm (A, B); 30 Mm (C); 80 Mm (D).

Figure 14. Photomicrographs of (A–I) Strombidium apolatum nov. spec. and (J–N) Heterostentor shenae after protargol impregnation. (A) Dorsal view, to show the gap between the equatorial and ventral kinety (arrow); (B) dorsal view, black arrow marks the macronucleus, whereas the white one indicates the end of ventral kinety; (C) ventral view, white and black arrows point to the kinety-gap and macronucleus, respectively; (D, H) macronucleus; (E) dorsal view, to show the equatorial kinety and the girdle (arrows); (F) ventral view, arrowheads mark the inconspicuous buccal membranelles, whereas the arrow points to the cytopharynx; (G) ventral view, focusing at surface level, arrow indicates the newly formed oral primordium, arrowheads mark the equatorial kinety; (I) ventral view, to show the girdle (black arrows) and the equatorial kinety (white arrows); (J) dorsal side of anterior portion, to show the adoral zone of membranelles; (K, M) ventral view, arrow indicates the proximal end of adoral zone of membranelles, while the arrowheads in (K) mark the suture, where some kineties are shortened; (L) to show some irregularly arranged membranelles (arrows); (N) caudal view, to show the thigmotactic area, where the basal bodies are densely arranged (arrows).