New Contribution to the Morphology and Taxonomy of Four Marine ...

160 W. Song et al.
by contracting and remaining motionless for a short
while.
Infraciliature as shown in Figs 28 and 29. Adoral zone
of membranelles about 2/5 of cell length after fixation
and of H. diademata-pattern, i.e. distal end reaches
right margin of cell and extends posteriorly, always in
two parts with a small gap between them (arrowheads
in Fig. 28). Cilia of anterior part of adoral zone of
membranelles prominent and considerably longer (about
20 µm long) than those of posterior part. Bases of
membranelles about 8-15 µm long, those in distal portion
distinctly shorter than those in proximal portion (Fig. 28).
Paroral membrane long and lies parallel to endoral
membrane (Fig. 28).
Frontal and transverse cirri strong, about 15-20 µm in
length, other cirri ca 12-15 µm long. Of the 4 frontal cirri,
3 anteriormost ones significantly enlarged and positioned
on anterior cell margin. Buccal cirrus medium in size,
conspicuously shifted anteriad. Two small, relatively
weak frontoterminal cirri positioned close to distal end of
adoral zone of membranelles. Midventral cirral rows
continuous with frontal cirri and extending close to
posterior transverse cirri (Fig. 28); cirri arranged in
typical zig-zag pattern. Transverse cirri highly developed
and arranged in a long row, which extends anteriorly
almost half cell length (Fig. 28). Marginal rows distinctly
separated at posterior end; anterior end of left marginal
row characteristically bent towards central region of
body (double-arrowhead in Fig. 28).
Consistently with 5 dorsal kineties extending over
entire length of body, 1 or 2 of which are usually situated
on lateral sides (Figs 28, 29). Dorsal cilia about 3-5 µm
long.
Comparison and discussion. With reference to the
body shape and basic pattern of infraciliature, especially
the structure of buccal apparatus, Holosticha
heterofoissneri should be compared with H. diademata,
H. pullaster, H. foissneri and H. spindeleri.
Both Holosticha diademata and H. pullaster are
smaller than H. heterofoissneri (70-140 and 60-90 µm
long respectively vs. 140 µm long) and consistently have
only 2 macronuclear segments (vs. 14-21), hence they
can be clearly separated from the latter (Tucolesco
1962, Foissner 1980, Wilbert and Kahan 1981, Wilbert
1986, Foissner et al. 1991, Petz et al. 1995, Hu and Song
1999) (Table 4).
Holosticha spindeleri is characterized by having an
extremely elongate membranelle at the posteriormost
end of the adoral zone of membranelles (vs. absent in
H. heterofoissneri) and a maximum of only 4 (vs. 14-
21) macronuclei (Petz et al. 1995).
Holosticha foissneri is evidently related to
H. heterofoissneri. The former differs from the latter
mainly in the number and distribution pattern of macronuclear
segments (5-11 arranged in a linear pattern vs.
14-21 forming an elongated U-shaped pattern around
margin of cell). Additional differences include the numbers
of adoral membranelles (26-36 vs. 41-49), dorsal
kineties (4 vs. 5) and cirral pairs in midventral rows
(16-20 vs. 12-15) (Table 4).
Cyrtohymena marina (Kahl, 1932) (Figs 30-37,
54-59; Table 5)
Syn. Steinia marina Kahl, 1932
To the best of the authors’ knowledge, no reinvestigations
on this species have been conducted using modern
methods. We hence suggest a new diagnosis based on
our observations.
Improved diagnosis. Medium-size marine
Cyrtohymena 100-150 x 30-50 µm in vivo, body elongate
oval in outline shape. 32-42 adoral membranelles;
consistently 8 frontal, 5 ventral, 5 transverse and 2 to
3 caudal cirri; 17-21 left and 19-25 right marginal cirri;
2 to 3 caudal cirri; 4 complete and one fragment-like
dorsal kineties; 2 macro- and 2-5 micronuclei; single
contractile vacuole in anterior body half; cortical granules
fine, inconspicuous, very sparsely distributed.
Morphological descriptions. Cells flexible, ca
120 x 40 µm in vivo, body usually ellipsoid and distinctly
broader than depicted by Kahl (1932) (Figs 30, 33);
length to width ratio usually 2.5-3:1 but in slender forms
about 3-4:1; posterior end often conspicuously narrowed
(Figs 32, 35). Left margin slightly to considerably convex,
right margin straight; highly flattened dorsoventrally
about 3:1 (Fig. 31). Buccal field prominent, almost half
cell length (Fig. 30).
Pellicle thin. Cortical granules colourless, usually fine
(ca 0.8 µm across) and sparsely distributed (Fig. 32), but
at least two other atypical forms were observed: in some
specimens, granules were undetectable, while in others,
numerous tiny granules (ca 0.2 µm) were observed
beneath pellicle, grouped in closely-spaced lines, giving
cell a cloudy appearance when viewed from dorsal side
(not figured).
Endoplasm colourless to greyish, in well-fed individuals
with many large food vacuoles containing small
ciliates, flagellates and diatoms, which often render the