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Protistology 7 (1), 5—33 (2012)
Protistology
Ciliates of the coastal zone in the southern basin of Lake Baikal (Part 1)
Ilham Alekperov1, Lubov Obolkina2 and Norbert Wilbert3
1 Institute of Zoology, National Academy of Sciences, Azerbaijan
2 Limnological Institute, Siberian Branch of Russian Academy of Sciences, Russia
3 Zoological Institute, University of Bonn, Germany
Summary
The paper presents a new revision of the ciliate fauna of the Lake Baikal shallow. During July and August 2008, free-living ciliates inhabiting macrophytes and sands in the open littoral zone of Lake Baikal were studied. Description of18 species are given; seven of them ( Urotricha baikalensis Alekperov, Obolkina, Wilbert sp. n., U. pseudovenatrix Alekperov, Obolkina, Wilbert sp. n., Prorodon atypicus Alekperov, Obolkina, Wilbert sp. n., Frontonia disciformis Alekperov, Obolkina, Wilbert sp. n., F. cristallophora Alekperov, Obolkina, Wilbert sp. n., Condylostoma longicaudata Alekperov, Obolkina, Wilbert sp. n., Wilbertella baikalica Alekperov, Obolkina, Wilbert sp. n.) were described for the first time.
Key words: ciliates, fresh waters, Lake Baikal
Introduction
As it is well known, Lake Baikal is the largest and deepest freshwater lake in the world. The studies of protists in this ancient lake began since the expeditions of Moscow University in 190001. Later Swarzewsky (1928a, 1928b), Rossolimo (1926), and Cheissin (1930-1932) have found rich endemic fauna of parasites which was then revised by A.V. Jankowsky (1973,1982a, 1982b, 1982c, 1986, 2007). The first detailed study of free-living ciliates in Lake Baikal was carried out by N.S. Gajewskaja during 1926 through 1928 (Gajewskaja, 1928, 1929, 1932, 1933) who found a series of fascinating new taxa that were regarded as endemics for Lake Baikal for a long time, while later on some of those
taxa were found in other water bodies of the world. However, the peculiar habitats of the Lake Baikal shallow host very specific fauna, and biodiversity of free-living protists there excite a great interest in terms ofboth protist taxonomy and understanding of many unclear aspects of their evolution. The interstitial fauna, mesopsammon — a new freshwater community recently found in open Lake Baikal littoral sands (that means sands out of shallows and relatively well heated bays) (Obolkina, 1991, 1995, 2006) can be put as an example of the adaptive evolution of free-living ciliates. Psammophilous ciliates ofLake Baikal exhibit all the features of morphological adaptations typical to marine psammophilous ciliates (Remane, 1933, 1940, 1952) and have a series ofdivergent forms which are still poorly studied.
© 2012 The Author(s)
Protistology © 2012 Protistological Society Affiliated with RAS
The paper presents a new revision of the ciliate fauna of the Lake Baikal shallow. Free-living ciliates inhabiting macrophytes and sands in the open littoral zone of Lake Baikal were studied in July-August 2008.
Material and methods
The study site was located at the west shore of Lake Baikal near the river Angara outflow in the bay Listvenichny (51o52’N, 104o49’E) and 20 km north from the village Bol’shiye Koty (51o53’N, 105o03’E). This area is typical to the open (out of shallows and warm bays) littoral zone of Lake Baikal. It is formed by terraces of the abrasive shore slopes covered by stones of different sizes and also sand and gravel. The terraces are poorly inhabited by higher water plants while stones are covered by macrophytes. The Ulothrix zonata belt is the first one which stretches from the coast line down to 1.5 m depth within the surf zone. The area from 1.5 m down to 2.5-3.0 m depth is the Tetraspora cylindrica belt. At the depths down to 10-12 m, the Draparnaldioides spp. belt is located.
The samples were taken on sand-gravel beaches within the first and second macrophytes’ belts and on sandy bottoms at depths of 2.5 to 3 m. The beach ground was a mixture of gravel, 40 to 80 %, rough-and mid-grained sand, 22 to 63 %, and pebbles, to 20 %. The sandy bottom ground at the 2.5-3 m depths consisted of gravel, 15 to 30 %, rough- and mid-grained sand, 40 to 57 %, and fine-grained sand, 18 to 36 %.
In total, 115 samples were collected. The live samples were stored in a refrigerator and treated in vivo first using microscope MBS.
Ciliates were caught into a micro-capillary and observed using a compound microscope with magnifications of x 100 to x 1000. The infraciliature was revealed by silver nitrate impregnation according to Chatton and Lwoff(1930), protargol (Wilbert, 1975; Alekperov, 1992) and silver carbonate (Foissner et al., 1999) methods. Drawings and photomicrographs were made from total preparations taking into consideretion the in vivo observations. All the morphometrical measurements were performed on not less than 10 individuals.
Holotypes for new species are deposited in the Limnological Institute, Siberian Branch of Russian Academy of Sciences and paratypes in the Institute of Zoology, National Academy of Sciences of Azerbaijan.
Species description
Urotricha baikalensis Alekperov, Obolkina, Wilbert sp. n. (Fig. 1, 1-4; Plate 1, 1-2, 4; Table 1)
Diagnosis. Obovoid or rounded cells of medium size, 45-70x40-60 ^m, with very small caudal cilia-free area and one caudal cilium. 40-60 somatic kineties, with kinetosomes located zigzag-like and characteristic cilia-free strip behind the brosse. The brosse consisting of three fragments: one parallel somatic kineties row of 10-12 dikinetids and two short oblique rows of 4 dikinetids each.
Type locality. Littoral zone in the southern basin of Lake Baikal on Ulotrix aggregations.
Type specimens. Typical preparations, holotype Baikal 2008 B-5, in the Limnological Institute, Siberian Branch of Russian Academy of Sciences and paratypes B-4 and B-6 in the Institute of Zoology, Baku, Azerbaijan.
Etymology. The species was called so because it was found in Lake Baikal.
Description. Rounded or obovoid cells ofmiddle size (45-70x40-60 ^m after impregnation), coloured from dark-green to bright green due to abundance in food vacuoles containing Ulothrix zoospores and algae. The posterior end more light. Distinct peripheral fringe offusiform extrusomes 3-4 ^m long in live specimens. Pharynx conspicuous, short.
Apical cytostome surrounded by a circumoral kinety consisting of 28-30 dikinetids and two circumoral adesmokineties (rows of double granules). Short cilia, 6-7 ^m long, set into 40-60 meridian rows with kinetosomes are situated zigzag-like a little bit not reaching the rear end of cell. Very small posterior cilia-free pole with a single inconspicuous caudal cilium 11-12 ^m long is on the rear end of cell. This blank posterior pole of impregnated cells covered by a dense irregular silverline system looks like cilia-free area absent and clearly visible only in a live specimens. Rectangular silverline meshes between somatic rows.
Combined-type brosse positioned lower the circumoral area not interrupting it and consisting of 3 fragments different in size. The first row (fragment 1) parallel to somatic kineties, formed by 10-12 dikinetids. Behind it, two short oblique rows consisting of 4 dikinetids each. One somatic row abuts on fragment 3 of brosse. A wider distance between it and the next right somatic row looks like a cilia-free strip and is characteristic of the species (Fig. 1).
Fig. 1. 1-4. Urotricha baikalensissp. n.: 1 — general view, 2 — nuclei, 3 — apical side, 4 — posterior view; 5-7— Urotrichapseudovenatrixsp. n.: 5 — general view, 6 — silverline system, 7— nuclei, 8 — Prorodon atypicussp. n. — general view; 9 — Lacrymaria binucleata sp. n. — general view; 10, 11 — Lacrymaria minuta Dragesco, 1960: 10 — in vivo; 11 — general view after silver nitrate impregnation.
Plate 1. 1-2 — Urotricha baikalensis sp. n.: 1 — general view, 2 — apical end, 3-4 — Urotrichapseudovenatrix sp. n.: 3—general view, 4 - posterior view; 5-6 — Prorodon atypicus sp. n.: 5 — general view; 6 — apical end, 7 — Lacrymaria minuta Dragesco, 19б0 — general view.
The excretory pore of the contractile vacuole is impregnated in the end of the strip, on the border of the cilia-free area. Contractile vacuole subtermi-nally positioned.
Fast motion along a spiral trajectory with frequent change of depths in the water column.
Occurrence and ecology. It occurs during the summer time in the two first macrophyte belts; viz.
U. zonata and T. cylindrica, in the littoral zone round Lake Baikal. Maximal development in June-July. Feeding on Ulothrix zoospores and diatom algae.
Discussion. About 9 Urotricha species have a single caudal cilium (Alekperov, 2005). This new species is close to U. sphaerica and U. dragescoi, by abundance in cilia rows and size (Groliere, 1977; Foissner et al., 1999). It differs from them by the
liable 1. Biometric characteristics of Urotricha baikalensis Alekperov, Obolkina, Wilbert sp. n. (hereafter: x, mean value; M, median; SD, standard deviation; SE, standard error; CV, coefficient of variation; Min, minimum value; Max, maximum value; n, number of objects analyzed).
Character
x
M
SD
SE
CV
Min
Max
Body length, pm
Body width, pm
55.0
48.0
50.0
47.5
10.274
5.375
3.249
1.7
18.68
11.198
45.0
40.0
70.0
60.0
10
10
Nematodesmal rods number
16.8
16.5
1.549
0.49
9.220
15.0
20.0
10
Kinetids in the bross fragment N1 (dikinetids counted as single kinetal units)
Kinetids in the bross fragments N2 and N3 (dikinetids counted as single units)
Macronucleus length, pm
19.9
20.0
1.969
0.623
9.894
18.0
23.0
10
Number of somatic kineties
n
10
0
0
0
10
10
specific structure of brosse, circumoral ciliature, characteristic cilia-free strip positioned behind the brosse, and very small cilia-free caudal area. These features distinguish it from other Urotricha species.
Urotricha pseudovenatrix Alekperov, Obolkina, Wilbert sp. n. (Fig. 1, 5-7; Plate 1, 3; Table 2)
Diagnosis. One of large Urotricha representatives. Oval cells reach 130 ^m in size with contractile rear half ofbody. б0-У0 meridional ciliary rows, one of them abutting to the fragment 3 of the brosse. Small cilia-free pole area has 5-У caudal cilia. Brosse consisting of 3 typical oblique fragments parallel one to the other. The first row (fragment 1) formed by 14-1б dikinetids and two others consisting of 10-12 dikinetids each. Apical cytostome surrounded by two circumoral adesmokineties.
Type location. The species was found in heterogeneous sands in the littoral zone of Lake Baikal.
Type specimens. Typical preparations, holotype Baikal 2008 B-3, in the Limnological Institute, Siberian Branch of Russian Academy of Sciences and paratypes B-4 and B-6 in the Institute of Zoology, Baku, Azerbaijan.
Description. Alive cells 95-135 ^m in size (95-135 ^m for fixed specimens) with oval body shape sometimes slightly narrowed in the caudal area. The contractile posterior half of the body can squeeze with forming longitudinal folds. Cytoplasm colourless, frequently abundant in 2-3 ^m long rod-
like inclusions therefore the ciliate looks like dark-grey. A part of the U. pseudovenatrix sp. n. population, about 25 % (as a rule, most large individuals), with transparent endoplasm without food objects. Two kinds of extrusomes: inconspicuous peripheral layer with densely spaced fusiform extrusomes, 4-5 ^m long, and mucocysts on the posterior blank end.
Apical cytostome surrounded by circumoral kinety with 26-32 dikinetids. Cytopharynx is conspicuous and short.
60-75 meridional somatic rows of cilia ended round the unciliated posterior area. One of them abuts to third fragment of brosse. Pore of the contractile vacuole impregnated at the posterior end of this somatic row. Somatic cilia about 10-12 ^m long. 5-7 firm caudal cilia 15-16 ^m long arranged on the blank posterior area.
The brosse consisting of 3 oblique fragments parallel one to the other. The fragment 1 of 14-16 dikinetids and fragments 2 and 3 of 10-12 ones.
Silverline system genus-typical: rectangular on the body and honeycomb on the blank area. Kinetosomes of somatic cilia positioned on the argyronema (direct connecting line).
Contractile vacuole is terminal.
Oval macronucleus, 27-35 ^m long, with distinct nucleoli and one spherical micronucleus.
It swims not very fast interrupted by jumps and time to time attaching to sand grains.
Occurrence and ecology. Psammophilous species. Omnivorous and predator. Food vacuoles containing algae, ciliates etc.
Character
x
M
SD
SE
CV
Min
Max
Body length, pm
Body width, pm
Macronucleus length, pm
Kinetids in the bross fragment N1 (dikinetids counted as single kinetal units)
Kinetids in the bross fragments N2 and N3 (dikinetids counted as single units)
Number of somatic kineties
Caudal cilia number
115.5
89.85
30.7
65.5
6.3
117.5
90.0
30.0
65.0
6.5
14.034
4.485
3.199
4.972
0.823
4.438
1.418
1.012
1.572
0.260
12.151
4.992
10.420
7.591
13.063
95.0
81.0 27.0
60.0
5.0
135.0
96.0
35.0
75.0
7.0
10
10
10
10
10
n
10
10
Discussion. There are known only 2 previously described Urotricha species, U. venatrix Kahl, 1935 and U. simonsbergeri Foissner, Berger and Schaumburg, 1999, with body longer than 100 ^m.
This species differs from U. venatrix by much lower number ofsomatic rows, 60-75 versus 98-127 for U. venatrix, caudal cilia (5-7 versus 12) and by another position ofbrosse fragments: for U. venatrix, fragments 1 and 2 oblique and parallel one to the other, fragment 3 begun at the lower end of the fragment 2 while for baikalian U. pseudovenatrix specimens, all the three fragments oblique and parallel one to the other.
The new species differs from U. simonsbergeri by much lower number of somatic rows, 73-109 for U. simonsbergeri, and caudal cilia (5-7 vs. 18-30), and mainly by another structure and position of the brosse fragments equal to 16 for U. simonsbergeri.
New species differs from Urotricha spp. with 4-6 caudal cilia (U. castalia, U. alveolata, U. matthesi and U. matthesi trichita) mainly by its size, broadly oval and contractile body, structure and position of brosse very similar to this one of Holophrya species with dexiotrop brosse. It differs from them by the blank posterior pole area typical for genus Urotricha.
Prorodon atypicus Alekperov, Obolkina, Wilbert sp. N. (Fig. 3, 8; Plate 1, 5-6; Table 3)
Diagnosis. Oval to spherical ciliates of middle size, 120-145x80-95 ^m. Apical cytostome with 2026 nematodesmes. 50-61 somatic ciliary rows. The brosse formed of only two long (40-50 ^m) rows of dikinetids. 10-14 caudal cilia 18-25 ^m long. Oval macronucleus with large nucleoli and one ellipsoidal
micronucleus. Contractile vacuole with 3-5 pores in the caudal end of body. Freshwater species.
Type locality. The species was found in the littoral zone of southern Baikal on fine sand.
Type specimens. Typical preparations, holotype Baikal 2008 B-3.
Description. Oval to spherical ciliates, 130— 170x90—110 ^m in size. Apical cytostome with 2026 nematodesmes. Cytopharynx clearly seen only in living cells, 40-55 ^m long. The somatic ciliature consists of 50-60 rows, of which one unipolar row begins at brosse finally terminating at the caudal end. Brosse consisting of two densely spaced rows of dikinetids, 38-45 dikinetids in each row. According to Hiller and Bardele (1988), the brosse of P. atypica sp. n. of “dexiotrop” configuration.
Cytoplasm transparent with no inclusions, some cells contain diatom algae. Oval macronucleus up to 35 ^m long with large nucleoli. Oval micronucleus located close to macronucleolus. Nuclear apparatus in the posterior quarter of the body in most of the specimens. Contractile vacuole at the caudal end with 3-5 pores of contractile vacuole impregnated.
Discussion. The structure (presence of only two rows) and position of the brosse of P. atypica sp. n. make it clearly distinct from all known Prorodon species. According to Hiller and Bardele (1988) dexiotrop pattern of the brosse is typical for 5 previously known Prorodon species: P. armatus Dx., 1966, P. ovum Ehrb, 1831, P. palustris Puyt. et Savoie, 1968, P. teres Ehrenberg, 1838 and P. parafricanus Dragesco et Dragesco-Kerneis, 1986, as well as P. atypicus sp. nov. Most of modern Prorodon species, belonging to all 4 groups suggested by Hiller and Bardele, have a brosse including 3 rows of dikinetids, except for the two species, P.
Fig. 2. 1-3 — Spathidiumprocerum Kahl, 1930: 1- in vivo, 2 — general view, 3 — nuclei; 4 — Zosterodasys fluviatilis Fernandez-Leborans and Alekperov, 1996 — general view ofventral side; 5-8 — Cinetochilum margaritaceum Perty, 1849: 5 — ventral side, 6 — nuclei, 7 — dorsal side, 8 — caudal cilia complex.
Character x M SD SE CV Min Max n
Body length, pm 125.9 127.5 13.763 4.352 10.932 120.0 145.0 10
Body width, pm 88.2 88.5 4.733 1.497 5.366 80.0 95.0 10
Number of somatic kineties 56.9 57.5 3.604 1.14 6.334 50.0 61.0 10
Length of the dorsal brush, pm 45.9 45.0 3.479 1.1 7.580 40.0 50.0 10
Kinetids in the right bross row (dikinetids counted as single kinetal units) 41.0 41.0 2.357 0.745 5.749 38.0 45.0 10
Kinetids in the left bross row (dikinetids counted as single kinetal units) 38.9 39.0 1.449 0.458 3.725 37.0 41.0 10
Caudal cilia number 12.3 12.0 1.636 0.517 13.301 10.0 14.0 10
Macronucleus length, pm 39.2 40.0 4.29 1.356 10.944 30.0 45.0 10
Micronucleus size, pm 14.7 15.0 3.057 0.967 20.8 10.0 18.0 10
Nematodesmal rods number 22.9 22.5 2.234 0.706 9.755 20.0 26.0 10
Number of CVP 3.6 3.0 0.843 0.267 23.417 3.0 5.0 10
parafricanus Dragesco et Dragesco-Kerneis, 1986, with 4 rows of the dorsal brosse, and P. atypicus sp. n., with only 2 rows of the brosse. We assume that this character is sufficient to identify P. atypicus as a new species.
Comments. Hiller and Bardele, 1988 proposed that the systematics of Prorodontidae needs to be clarified. We share this opinion and consider further refinement ofthe taxonomic features known quite necessary. For instance, classification of the species based on the type of the brosse (aklitoloph, dexiotrop, aristerotrop and syntrop) is validated and seems to be at least a generic character. Since the species with a unique structure of the brosse, P. parafricanus and P. atypicus, are still awaiting detailed electron-microscopic examination, we suggest to consider them valid species from the group (genus?) with a dexiotrop pattern ofthe dorsal brosse.
Lacrymaria binucleata Song and Wilbert, 1989 (Fig. 1, 9 Table 4)
This species was found in Germany, in fresh waters near Bonn, and described by Song and Wilbert (1989) and, as far as we know, still not met in other places. Baikalian Lacrymaria binucleata was found on mid-grained sand, the south basin of the lake.
Cells 50-70 ^m in size in live specimens and 40-65 ^m in fixed ones with spindle-like body shape
pointed at the back end. Apical cytostome with 5-8 long nematodesma (extrusomes). Behind it, distinct broad neck with 9-14 kineties. Body covered by slightly spiral 9-14 kineties.
Transparent cytoplasm without inclusions. Contractile vacuole close to the caudal end. Two elongated macronucleus with single spherical micronucleus.
There are a few Lacrymaria species with two macronucleus: L. clavarioides Alekperov, 1984, L. bulbosa Alekperov,1984, L. issikkulica, Alekperov, 1997 and L. binucleata Song and Wilbert 1989. Baikalian individuals of L. binucleata differ from the original description by slightly bigger sizes, less narrow caudal end, larger number ofsomatic kineties (9-14 vs. 8-12 for type species), and slightly different nucleus shape: 2 globular nodules in the original description and stretched irregular macronucleus in baikalian specimens.
Lacrymaria minuta Dragesco, 1960 (Fig. 1, 10-11; Plate 1, 7; Table 5)
This species was first described from the French shore of the Atlantic ocean (Dragesco, 1960). Later it was found in the White Sea, Russia (Burkovsky,
1970), on the Atlantic shore ofAfrica (Dragesco and Dragesco-Kerneis, 1986) and in the psammon at the Saudi Arabian coastal zone (Al-Raseid, 2000).
L. minuta was found on the fine-grained sand, the south basin of Lake Baikal.
Fig. 3. 1-3 — Frontonia disciformis sp. n.: 1—ventral side, 2 — nuclei, 3 — dorsal side, 4-8 — Frontonia cristallophora sp. n.: 4—ventral side, 5 — nuclei, 6 — dorsal side, 7 — ventral side ofsecond population (psammon from Bol’shiye Koty bay), 8 — buccal ciliature.
Character
x
M
SD
SE
CV
Min
Max
Body length, pm 57.1 59.5 7.460 2.359 13.065 40.0
Body width, pm 19.8 20.0 2.658 0.841 13.424 15.0
Neck length, pm 9.7 10.0 1.494 0.473 15.402 8.0
Head length, pm 8.9 9.0 0.876 0.277 9.843 8.0
Numbesr °f s°matic 11.4 n.5 ^97 0.6 16.640 9.0
kineties
Macronucleus length, pm 22.0 22.5 1.633 0.516 7.423 20.0
Macronucleus width, pm 11.6 12.0 1.075 0.340 9.267 10.0
Number of macronuclei 2.0 2.0 0 0 0 2.0
Number of micronuclei 1.0 1.0 0 0 0 1.0
65.0
25.0
12.0 10.0
14.0
24.0
13.0
2.0 1.0
10
10
10
10
10
10
10
10
10
n
Cells 120-130 long in live specimens and 80-97 ^m long in fixed ones with elongated shape of body widened in the front part. Preservation changes the head shape from pointed to oval, almost spherical, and widening of the body front part is expressed more explicitly.
Form with characteristic to the genus subdivision of the organism into head, neck, and main body. 5-7 nematodesma (extrusomes) at the apical end of the body in silver-nitrate impregnation specimens. 3-5 diagonal rows on the head and neck. 8-9 rows of somatic kineties forming a slight spiral on the trunk. Kinetosomes linked one to the other in each row by argironema.
Transparent endoplasm, sometimes grey coloured due to swallowed small algae. Extrusomes 12-15 ^m in length.
Bean-like macronucleus (30 ^m) with one micronucleus close to it in equatorial part ofthe cell. Pore of the contractile vacuole impregnates close to caudal end of the body.
Fast motion along the spiral.
Baikalian individuals of L. minuta differ from those described in literature by smaller body size, usually 140-160 ^m according to Al-Rasheid (2000), and less spiralization of somatic rows.
Spathidium procerum Kahl, 1930 (Fig. 2, 1-3; Plate 2, 1; Table 6)
Widespread species inhabiting both aquatic and soil biotopes (Foissner, 1984; Alekperov, 1993). It was found in coastal fine-grained sands, the south basin of Lake Baikal.
Cells 130-160 ^m long in live specimens and 110140 ^m long in fixed ones. The body shape in vivo spindle-like dorso-ventrally flattened at the front end and with pointed back end. Slit-like apical cytostome (18-25 ^m) surrounded by distinct cytostome bulge and reinforced by abundant nematodesma distinct only in live specimens. Transparent endoplasm is grey to dark-grey coloured containing cells of small diatom and coccous algae.
25-32 somatic ciliary rows begin from cytostome bulge and finish at caudal body end. The brosse
Table S. Biometric characteristics of Lacrymaria minuta Dragesco, 1963.
Character
x
M
SD
SE
CV
Min
Max
Body length, pm Body width, pm Neck length, pm
Head length, pm
Number of somatic kineties
89.7
34.0 6.9
6.0 8.2
90.0
35.0
7.0
6.0 8.0
5.122
2.494
0.994
0.943
0.422
1.62
0.789
0.314
0.298
0/133
5.710
7.335
2.924
4.967
5.146
80.0
30.0
5.0
5.0
8.0
97.0
37.0
8.0
7.0
9.0
10
10
10
10
10
n
Plate 2. 1 — Spathidium procerum Kahl, 1930, general view; 2—Zosterodasys fluviatilis Fernandez-Leborans and Alekperov, 1996, ventral side; 3-4 — Sathrophilus muscorum (Kahl, 1931): 3 — ventral side, 4 — caudal cilia complex.
consisting of 3 rows of double kinetosomes different in length and positioned behind cytostome. Silver-line system is composed of small meshes tetragonal in shape.
Band-like macronucleus, with usually 3 or 4-5 micronucleus, positioned along longitudinal axis sometimes loop-like. Macronucleus band consisting of 3 or more loops in fixed cells.
Contractile vacuole positioned in the caudal end.
Zosterodasys fluviatilis Fernandez-Leborans and Alekperov, 1996 (Fig. 2, 4; Plate 2, 2; Table 7)
The species was first described from the fresh waters of north-west provinces of Azerbaijan (Fernandez-Leborans and Alekperov, 1996) and later was found in the middle part of the river Syr-Darya, Uzbekistan (Alekperov, 2005).
Cells of baikalian population 130-150 ^m long in live specimens and 108-140 ^m long in fixed ones with oval body shape slightly widened at the front end and dorsoventrally flattened. Cytostome, positioned in the centre of the front quarter of the ventral side, reinforced by 20-25 nematodesma. Synhymenium, consisting of paired kinetosomes and ended in the right part of the dorsal side, positioned lower the mouth along a diagonal line to the longitudinal body-axis.
Somatic ciliature consisting of 40-55 kineties on the ventral side and 40-50 on the dorsal side. In all - 100-115.Kineties surrounded the mouth from two sides, stretched against the synhymenium, and ended at the body back.
Cells transparent, contain many diatom algae.
3-5 contractile vacuole pores positioned along the caudal end. Cytopyge strip impregnates along the longitudinal axis of the back quarter of the dorsal side. Elongated (38-43 ^m) macronucleus with distinct nucleoli and single spherical micronucleus (3.2-3.8 ^m). 3-5 contractile vacuole pores are situated close to right ventral side.
Baikalian specimens differ from Z. fluviatilis, collected from the fresh waters of Azerbaijan and Middle Asia (Fernandez-Leborans and Alekperov, 1996; Alekperov, 2005), by much smaller sizes, higher number of cytostome nematodesma (22-25 vs. 14-16) and somatic rows (100-115 vs. 70-75), narrower macronucleus shape, and larger number of contractile vacuoles (3-5 vs. 1).
Table 6. Biometric characteristics of Spathidium procerum Kahl, 1930.
Character x M SD SE CV Min Max n
Body length, pm 125.2 127.5 11.516 3.642 9.198 110.0 140.0 10
Cytostom length, pm 22.4 23.0 2.319 0.733 10.353 18.0 25.0 10
Dorsal brash rows number 3.0 3.0 0 0 0 3.0 3.0 10
Number of somatic kineties 28.7 29.5 2.406 0.761 8.383 25.0 32.0 10
Caudal cilia number 9.6 10.0 1.506 0.476 15.688 7.0 11.0 10
Number of micronuclei 3.5 3.0 0.850 0.269 24.284 3.0 5.0 10
Table 7. Biometric characteristics of Zosterodasys fluviatilis Fernandez-Leborans and Alekperov, 1996.
Character x M SD SE CV Min Max n
Body length, pm 127.0 129.0 10.154 3.211 7.995 108.0 140.0 10
Body width, pm 91.0 90.0 4.028 1.274 4.426 85.0 98.0 10
Number of somatic kineties 107.5 108.5 4.859 1.537 4.52 100.0 115.0 10
Nematodesmal rods number 22.0 21.5 2.211 0.699 10.05 20.0 25.0 10
Distance from oral area to apical end, pm 21.8 22.0 2.741 0.867 12.573 18.0 25.0 10
Macronucleus length, pm 41.3 42.0 1.567 0.496 36.442 38.0 43.0 10
Macronucleus width, pm 7.25 7.3 0.268 0.0847 3.697 6.8 7.5 10
Number of micronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Micronucleus size, pm 3.55 3.6 0.227 0.0719 6.394 3.2 3.8 10
Number of CVP 3.9 4.0 0.876 0.277 22.462 3.0 5.0 10
Cinetochilum margaritaceum Perty, 1849 (Fig. 2, 5-8; Table 8) Body size of alive specimens 30-40 ^m long and 20-30 ^m long in fixed ones with oval body shape slightly narrowed in the front. Large buccal cavity positioned in the mid-body slightly right to median ofventral side, with arc-like undulating membrane on the right ofit consisting of the double zigzag row of large kinetosomes. On the left from lower part of the undulating membrane, cytostome with 12-16 running away fan-like supporting “oral rods”. Three membranelles (long M1, M2, and short M3) obliquely arranged over the cytostome. M2 slightly curved. Cilia-free suture positioned over M1 to apical pole and somatic rows running in two directions from it, 5 rows on the right and 5 ones on the left. Additional short row of 5-7 kinetosomes begins lower M2 and abuts against cytopyge, on the left. 5-6 somatic rows on the dorsal side. Silverline system consisting of tetragonal meshes. Kinetosomes of every somatic rows linked by argyronema. Short row of 6 kinetosomes (scutica) below the buccal zone. The cytopyge positioned along the longitudinal body-axis behind the cytostome.
Table S. Biometric characteristics of Cinetochilum margaritaceum Perty, 1849.
Character x M SD SE CV Min Max n
Body length, pm 26.9 28.0 3.784 1.197 14.067 20.0 30.0 10
Ventral somatic rows number 10.7 11.0 0.483 0.153 4.514 10.0 11.0 10
Dorsal somatic rows number 5.8 6.0 0.422 0.133 7.267 5.0 6.0 10
Cytostom supporting oral rods 13.9 14.0 1.595 0.504 11.475 12.0 16.0 10
Kinetosom number in short additional row, lower M2 5.9 6.0 0.876 0.277 14.847 5.0 7.0 10
Caudal cilia number 4.0 4.0 0 0 0 4.0 4.0 10
Postoral cilia number 6.0 6.0 0 0 0 6.0 6.0 10
Contractile vacuole pore impregnated on left side of caudal end and 4 caudal cilia on its right side.
Endoplasm transparent, without inclusions. Globular to oval macronucleus with distinct nucleoli and one globular micronucleus.
Baikalian individuals of C. margaritaceum differ from the literature descriptions (de Puytorac et al., 1974; Dragesco, Drageso-Kerneis, 1986; Foissner et al., 1999) by number of somatic rows (17 vs. 1922), smaller number of caudal cilia (4 vs. 5), longer left somatic row (SKn), a little bit other shape of M2 (without hook-like anterior portion) and regular silverline system on the dorsal side.
Frontonia disciformis Alekperov, Obolkina, Wilbert sp. n. (Fig. 3, 1-3; Plate 3, 1-2; Table 9)
Diagnosis. Freshwater Frontonia cells 140-200x100-140 ^m and 120-160x90-120 ^m long after fixation. 108-125 somatic rows, consistently postoral 5 while 5 vestibular kineties. Three peniculi composed of 4 rows each. Charac-teristic cilia-free postoral suture continued on the dorsal side from caudal end to equatorial part. One elongated macronucleus with one spherical micronucleus behind buccal cavity on the left. A ratio of buccal cavity length to body length is 0.23-0.30.
Type location. On the sands in the littoral zone of southern basin, Lake Baikal.
Type slides. One holotype (slide number Baikal 2008 N5) deposited in the Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russia and two paratypes (slide number Baikal 2008 N3 and slide number Baikal 2008 N9) deposited in the Institute of Zoology, NAS of Azerbaijan.
Description. Size in vivo 140-200x100-140 ^m and 120-160x90-120 ^m after impregnation. Oval disk-like flat body, broadly in front and obtusely pointed in back.
Buccal cavity occupying 0.23-0.30 of body length and deposited in anterior part of ventral side. Five vestibular kineties with densely arranged kinetosomes each and one double-rowed paraoral kinety on the right wall of it adjacent to cytostome. 3 peniculi positioned on left wall. P1 and P2 composed of 4 rows each and short P3 consisting of 4 rows of different length.
108-125 somatic rows, 48-55 from them arranged on the ventral side ofbody. 5 postoral rows begining posterior from the buccal cavity and ending at the postoral suture. Both anterior and postoral sutures distinct and continue to dorsal side. Unusually long postoral suture ended in the middle of dorsal side. Dorsal somatic rows ended on this suture. 2-3
Table 9. Biometric characteristics of Frontonia disciformis Alekperov, Obolkina, Wilbert sp. n.
Character X M SD SE CV Min Max n
Body length, pm 146,25 147,5 13.604 4.302 9.302 120.0 160.0 10
Body width, pm 99.0 95.0 9.369 2.963 9.464 90.0 120.0 10
Number of somatic kineties 117.3 117.5 5.736 1.814 4.89 108.0 125.0 10
Macronucleus size, pm 39.1 38.0 1.713 0.542 4.381 37.5 42.0 10
Micronucleus size, pm 3.9 3.5 0.994 0.314 25.487 3.0 5.0 10
Number of macronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Number of micronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Buccal zone size, pm 38.12 38.0 0.675 0.213 1.771 37.0 39.0 10
Distance from buccal zone to apical end, pm 37.5 37.5 0.471 0.149 1.256 37.0 39.0 10
Number of postoral rows 5.0 5.0 0 0 0 5.0 5.0 10
Number of vestibular rows 5.0 5.0 0 0 0 5.0 5.0 10
Ratio of buccal/body length 0.265 0.270 0.029 0.009 11.094 0.23 0.30 11
Number of CVP 2.0 2.0 0.816 0.258 40.8 2.0 3.0 10
excretory pores of contractile vacuole positioned on rear third of dorsal side close to postoral suture. Silverline system as in the other congeners with quadrangular meshes.
Cytoplasm dark coloured, filled with many diatoms.
Elongated macronucleus with one spherical micronucleus in depression positioned behind
buccal cavity on the front third of the body.
Movement spiralling, moderately fast with rotation around the longitudinal body axis.
Discussion. The described species F. disciformis sp. n. is morphologically close to one described from the psammon of the White Sea, F. tchibisovae Burkovsky, 1970. However there is a series of differences between these species. The baikalian
one is slightly smaller in body size (120-160 versus 132-240 ^m), with lower number of somatic rows (108-125 versus 127-149), and much higher a buccal cavity-to-body length ratio (0.23-0.30 versus
0.14-0.21). The number ofvestibular rows is 3-4 for F. tchibisovaeand 5 for the baikalian species. Besides mentioned above, F. disciformis possesses a larger number of contractile vacuole pores (2-3 versus 1), slightly another macronucleus shape.
The cilia-free suture extending onto the dorsal side of the body was to day observed only for F. tchibisovae Burkovsky, 1970 and F. lynni Long et al., 2005. Baikalian F. pseudotchibisovae sp. n. is distinguished by its hypertrophied cilia-free postoral suture reaching the middle part on the dorsal side of the body in some individuals. Besides that our species inhabits fresh waters in contrast with marine F. tchibisovae and F. lynni (Burkovsky, 1970; Long et al., 2005; Long et al., 2008).
Frontonia cristallophora Alekperov, Obolkina, Wilbert sp. n. (Fig. 3, 4-8; Plate 3, 3-4; Table 10)
Diagnosis. Freshwater species 50-65 ^m in size, 2-3 vestibular and 3-5 postoral rows. 30-38 somatic rows. Characteristic features of the species are
aggregations of light refractile crystals in anterior body area and large buccal cavity (20-25 ^m). Subequatorial contractile vacuole with 1-2 pores on dorsal side.
Type location. Found in psammon ofthe littoral zone, the southern basin, Lake Baikal.
Type specimens. The typical preparations -holotype (slide number Baikal 2008 N3) deposited in in the Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russia and paratypes (slide numbers Baikal 2008 N2 and N12) in the Institute of Zoology, NAS of Azerbaijan, Baku.
Description. Ciliates 60-70 ^m in size in vivo and 50-65 ^m in fixed specimens. Oval body shape slightly widened in front. Buccal zone positioned in the centre ofventral side. On the right in it, 3 rows of vestibular kineties composed of paired kinetosomes and paroral membrane also composed oflarge paired kinetosomes. Cytostome positioned in the centre of buccal cavity and on the left from it large arc-like peniculi P1, P2, and P3 different in length.
30-38 somatic rows in which kinetosomes set in triplets linked by argyronema. Postoral suture positioned below buccal zone on the left from 3-5 postoral rows. The most high ratio of buccal cavity
Table 10. Biometric characteristics of Frontonia cristallophora Alekperov, Obolkina, Wilbert sp. n.
Character x M SD SE CV Min Max n
Body length, pm 54.6 55.0 4.6 1.454 8.425 50.0 65.0 10
Body width, pm 37.25 37.25 1.875 0.593 5.034 35.0 40.0 10
Number of somatic kineties 33.8 34.5 2.3 0.727 6.805 30.0 38.0 10
Macronucleus length, pm 13.25 13.0 1.184 0.375 8.936 12.0 15.0 10
Micronucleus size, pm 1.83 2.0 0.302 0.0955 16.503 1.2 2.1 10
Number of macronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Number of micronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Buccal zone size, pm 22.7 22.5 2.214 0.7 9.753 20.0 25.0 10
Distance from buccal zone to apical end, pm 11.55 11.5 1.117 0.353 9.671 10.0 13.0 10
Ratio of buccal/body length 0.347 0.33 0.0391 0.013 11.268 0.3 0.4 10
Number of CVP 1.8 2.0 0.422 0.133 23.444 1.0 2.0 10
Vestibular rows number 3.0 3.0 0 0 19.846 3.0 3.0 10
Postoral rows number 3.5 3.0 0.707 0.224 20.2 3.0 5.0 10
length to body length for the genus Frontonia equals to 0.3-0.4.
Anterior part of body looks very dark due to cluster of small crystals. This one is a characteristic feature of species. Transparent cytoplasm without other inclusions frequently with several cells of diatom algae. Bean-like macronucleus with distinct nucleoli and adjacent to it globular micronucleus in back halfof the body at the left. Fusiform extrusomes,
4-5 ^m long, densely distributed in the cortex.
On dorsal side, impregnated 1-2 pores of contractile vacuole. One contractile vacuole positioned in the posterior half of body on the right side.
Discussion. Presently the genus Frontonia includes 42 described species , and most of them, 30 species, are found in fresh waters. By body size, F. crystallophora sp. n. belongs to smallest representatives of the genus. The closest to our species is F. minuta Dragesco described from fresh waters of Western Africa (Dragesco, 1970). However there are differences in number of somatic rows, 32-38 kineties for F. crystallophora and 5056 kineties for F. minuta. Besides, our species has
3 postoral rows while F. minuta has 6. The buccal cavity of F. crystallophora is very large, it has only one micronucleus while F. minuta 2-3 ones. And baikalian species has no symbiotic algae.
It is necessary to mark F. multinucleata as most close to our species by morphology among other species. But despite their resemblance in cell size and some details of the buccal ciliature, there are significant differences, viz. another structure of nuclear apparatus (F. multinucleata Long et al., 2008 has several macronuclei); besides this is marine psammophilous species. Also it is necessary to mark characteristic to F. crystallophora sp. n. crystals, positioned in the body front which presence we have stressed in the species name.
Only one freshwater species, F. bullingtoni Dragesco, 1960 has crystal inclusions yet. By small body size and shape, number of ciliary rows, and characteristic accumulation of crystals in anterior body area, baikalian Frontonia strongly resembles F. bullingtoni from sands of Lake Leman. The former distinctly differs from the latter by larger mouth (1/3 of body length vs. 1/5), another shape of the macronucleus (bean-like vs. spherical shape in F. bullingtoni) and smaller exrtusomes.
Frontonia roque Dragesco, 1970 (Fig. 4, 1-3; Plate 4, 2; Table 11)
The species was found in both biotopes, sands and macrophytes, in the littoral zone of the
southern basin of Lake Baikal. Below we give a short description of baikalian specimens exhibiting minor distinctions from those described in the literature.
Cells 150-180 ^m long in live specimens and 130-160x80-100 ^m in size after impregnation. Ellipsoidal body shape slightly broader at the anterior end. Buccal zone 25-32 ^m in size, positioned in the front area of the ventral side. Three vestibular kineties composed of monokinetids in the upper part and of triplet kinetosomes in the lower area. Double-rowed paroral membrane running closely to the cytostome at right and three peniculi different in length located on the left wall of the buccal cavity. P1 and P2 composed of four rows of kinetosomes each and P3 of three kineties. 4-5 postoral somatic rows lower the peniculi from the margin of the buccal cavity to the postoral suture.
Somatic ciliature composed of 60-70 kineties rows arranged with triple kinetosomes and connected by argironema. Inconspicuous preoral cilia-free suture running from the upper margin of the buccal cavity to apical pole.
Transparent cytoplasm usually filled with diatomic algae. Elongated macronucleus with numerous nucleoli and single spherical micronucleus. One contractile vacuole positioned at a rear quarter of the body. Its one pore impregnated on the dorsal side ofthe cell. Genus-typical silverline system with quadrangular cortical meshes.
Baikalian specimens of F. roque slightly differ from its original description (Dragesco, 1970) in number of ciliary rows (60-70 versus 62-82) and vestibular kineties (3 versus 4).
Frontonia vesiculosa da Cunha, 1914 (Fig. 4, 4-5; Plate 4, 3; Table 12)
The species was not recorded in Lake Baikal earlier. Brief morphological characteristics of the representatives of Baikal population are provided based on in vivo observations and examination ofthe whole mounts impregnated in silver nitrate.
Living specimens 190-280 ^m in size, fixed cells — 160-230 ^m. Ellipsoid body, anterior part more pointed than the posterior end. Living cells include a well defined subpellicular layer of trichocysts.
Relatively small buccal cavity located in the anterior third of the ventral part of the body. Right side of the buccal cavity with three vestibular rows of dikinetids. Undulating membrane, cytostome left of the cavity and the left side of the buccal cavity with three peniculi P1, P2 and P3, each consisting of four densely spaced rows. Postoral suture separating the ventral side into two parts and terminating at the caudal end begins below
Fig. 4. 1-З — Frontonia roquei Dragesco, 19У0: 1 — ventral side, 2 — nuclei, З — ciliary pattern of oral apparatus, 4-5 — Frontonia vesiculosa da Cunha, 1914: 4 — ventral side, 5 — nuclei.
the level of cytostome. 5-б short postoral kineties begin posterior to the buccal cavity reaching the postoral suture.
90-110 somatic rows with triple rows of kinetosomes, 45-50 of which located on the ventral side of the body, 55-б0 — on the dorsal side.
Endoplasm dark brown, generally filled with small algae. Nuclear apparatus represented by elongate macronucleus (40-б0 ^m) with large nucleoli and 4-У micronucleoli.
Six pores of excretory vacuoles impregnated along the right side of the ventral part of the body.
F. vesiculosa from Baikal differs from the specimens described so far by smaller sizes. According to Dragesco et Dragesco-Kerneis, 1986, African specimens of this species are as large as 660 ^m, specimens from Cameroon — 900 ^m, those from Uganda and Benin — 430 and 560 ^m, respectively. Baikal specimens have almost half as many somatic rows. It should be noted that baikalian F. vesiculosa
Plate 4. 1 — Cyclidium glaucoma Müller, 1786: ventral side; 2 — Frontonia roquei Dragesco, 1970: ventral side; 3 — Frontonia vesiculosa da Cunha, 1914: ventral side; 4-5 — Strombidium rehwaldii Petz and Foissner, 1992: 4—ventral side, 5— dorsal side; 6— Strobilidium caudatum (Fromentel, 1870): general view; 7 — Limnostrombidium viride (Stein, 1867).
specimens have 6 stable contractile vacuoles, whereas their number in the African specimens varies from 4 to 6 depending on the population.
Cyclidium glaucoma Müller, 1786 (Fig. 5, 1-3; Plate 4, 1; Table 13)
Very common species inhabiting macrophyte belts in the littoral zone, for the first time registered in Baikal by N.S. Gaevskaya (Gajewskaja, 1933).
Living specimens 17-28 ^m, fixed cells — 12-
20 ^m. Body oval, anterior end narrower. Apical
end flatttened with a small non-ciliated zone at the pole.
Anterior half of the ventral side occupied by buccal cavity, its right and left sides border an L-shaped, curved undulating membrane consisting of large zig-zag arranged kinetosomes. The number of undulating membrane kinetosomes varies from 38 to 52 depending on the cell size. Membranelles M1, M2, M3 located to the left, cytostome with 20-
21 oral ribs, extending toward the posterior region of the undulating membrane, below. Subequatorial cytopyge posterior to the buccal cavity. Contractile vacuole pore impregnated subterminally on the kinety 2 below cytopyge level.
Somatic ciliature consists of 12-15 somatic rows. Each row includes 13-16 pairs ofkinetosomes connected by argironeme. At the ventral side, two somatic rows on each side of the buccal cavity. 8-10 somatic rows on the dorsal side. One long (8-10 ^m) caudal cilium in the posterior part of the body. Spherical macronucleus with a single micronucleus in the anterior part.
Our specimens of Cyclidium glaucoma differ from other representatives of this species (Dragesco et Dragesco-Kerneis, 1986; Foissner et al., 1994) by a shorter undulating membrane beginning from the level of M2, and location of the contractile vacuole pore. From the specimens C. glaucoma, described from the Germany (Didier and Wilbert, 1981) our specimens differs by constant double kinetosomes in the somatic rows.
Strombidium rehwaldii Petz and Foissner, 1992 (Fig. 5, 4-5; Plate 4, 4-5; Table 14)
The species was first found and described from fresh waters ofthe river Amper, Germany (Petz and Foissner, 1992).
Below we give a short morphological description of this species found in the sub-bottom layer in the littoral zone, the southern basin of Lake Baikal.
Cells 40-65 ^m in size in live specimens and 35-50 ^m in their fixed state. Ellipsoidal body shape slightly narrowed at the anterior end. Wreath, composed of 10-12 outer (collar) membranelles 2022 ^m in size, surrounding the acentric oral cavity in the body front. Diagonal row comprising 8 to 9 short, 7-10 ^m long, inner (or buccal) membranelles running from the left margin of more long anterior membranelles. Paroral membrane running from the right margin of the anterior membranelles to rear margin of the buccal membranelles and bringing the oral cavity to a close. Equatorial belt composed of dikinetids possessing one short cilium 5^m long each
Character x M SD SE CV Min Max n
Body length, pm 145.3 149.0 12.945 4.093 8.909 130.0 160.0 10
Body width, pm 90.031 90.0 5.375 1.621 5.970 80.0 100.0 10
Number of somatic kineties 65.5 65.0 4.378 1.384 6.684 60.0 70.0 10
Number of postoral kineties 4.273 4.0 0.467 0.141 10.929 4.0 5.0 10
Number of vestibular kineties 3.0 3.0 0 0 0 3.0 3.0 10
Number of macronuclei 1.0 1.0 0 0 0 1.0 1.0 9
Number of ciliary rows in Pj 4.0 4.0 0 0 0 4.0 4.0 9
Number of ciliary rows in P2 3.6 4.0 0.516 0.163 14.333 3.0 4.0 9
Number of ciliary rows in P3 3.0 3.0 0 0 0 3.0 3.0 9
Ratio of buccal/body length 0.194 0.190 0.0126 0.0040 6.495 0.18 0.21 10
Number of CVP 1.0 1.0 0 0 0 1.0 1.0 9
and not closed on the ventral side. 18-21 dikinetids on the dorsal side of the equatorial row and 13-14 on the left ventral side and correspondingly 14-16 on the right one. Small ventral row of10-11 dikinetids with one cilium, only each running along the rear ventral body side from the cilia-free area between right and left fragments of the equatorial row to the caudal body end.
Table 12. Biometric characteristics of Frontonia vesiculosa da Cunha, 1914.
Character x M SD SE CV Min Max n
Body length, pm 203.89 210.0 27.81 9.27 13.64 160.0 230.0 9
Body width, pm 69.33 70.0 4.74 1.58 6.84 60.0 75.0 9
Number of somatic kineties 100.89 100.0 8.21 2.74 8.14 90.0 110.0 9
Vestibular kineties number 3.0 3.0 0 0 0 3.0 3.0 9
Postoral kineties number 5.44 5.0 0.53 0.176 9.68 5.0 6.0 9
Macronucleus size, pm 50.89 50.0 6.58 2.19 12.94 40.0 60.0 9
Micronucleus size, pm 2.08 2.10 0.16 0.05 7.89 1.8 2.3 9
Number of macronuclei 1.0 1.0 0 0 0 1.0 1.0 9
Number of micronuclei 4.78 4.0 1.09 0.36 22.88 4.0 7.0 9
Ratio of buccal/body lenth 0.14 0.13 0.03 0.01 21.74 0.12 0.21 9
Number of CVP 6.0 6.0 0 0 0 6.0 6.0 9
Fig. 5. 1-3 — Cyclidium glaucoma Müller, 1786: 1 — ventral side, 2 — nuclei, 3 — dorsal side; 4-5 — Strombidium rehwaldii Petz and Foissner, 1992: 4 — ventral side, 5 — dorsal side (protargol impregnation).
Character X M SD SE CV Min Max n
Body length, pm 15.900 16.000 2.961 0.936 0.019 12.0 20.0 10
Body width, pm 14.100 14.500 3.178 1.005 22.539 10.0 15.0 10
Cytostomal ribs number 24.500 24.500 3.028 0.957 12.359 20.0 21.0 10
Number of somatic kineties 13.1 13.0 1.101 0.348 8.405 12.0 15.0 10
Macronucleus diameter, pm 3.190 3.200 0.242 0.0767 7.586 2.8 3.5 10
Micronucleus diameter, pm 1.330 1.350 0.134 0.0423 10.075 1.100 1.500 10
Undulating membrane kinetosome number 46.300 48.500 5.122 1.620 11.063 38.0 52.0 10
Caudal cilium length, pm 9.000 9.000 0.816 0.258 9.067 8.0 10.0 10
Transparent cytoplasm comprising sometimes one or two swallowed cells of small diatom and green algae.
Macronucleus large in comparison with the body size, 12-16 ^m, with near-ellipsoidal shape and including numerous nucleoli. One globular to oblong micronucleus.
Contractile vacuole positioned on the ventral side lower the left margin of the adoral membranelles in the same manner as given in the original description.
Baikalian individuals of S. rehwaldii are similar in principal to their original description but slightly differ by more stable number of dikinetids in the equatorial and ventral rows, 49 to 55 versus 34 to 55 and correspondingly 10 to 11 versus 10 to 18. As is originally described, the species was also found in sub-bottom layers and silted sands. S. rehwaldii does not inhabit plankton and the pelagic zone.
Limnostrombidium viride (Stein, 1867) (Fig. 6, 2-3; Plate 4, 7; Table 15)
Only solitary specimens of this species were registered in the samples collected from some localities in the littoral zone of Southern Baikal overgrown by aquatic vegetation. Brief description of the species based on examination of silver nitrate-impregnated specimens is given below.
Living organisms 50-65 ^m in size, fixed cells — 45-60x40-48 ^m. Body conical, constricted at the caudal end. Buccal cavity lined by 10-11 collar and 12-15 buccal membranelles, the latter extend from the left margin of collar membranelles along the left side of the buccal cavity up to its lower margin. Undulating membrane borders the right side of the buccal cavity. A circumferential equatorial ciliary row consisting of pairs of basal bodies with solitary
Table 14. Biometric characteristics of Strombidium rehwaldii Petz et Foissner, 1992.
Character X M SD SE CV Min Max n
Body length, pm 42.2 42.5 5.903 1.867 13.988 35.0 50.0 10
Body width, pm 23.0 23.0 2.49 0.79 10.84 20.0 27.0 10
Collar membranelles number 11.5 12.0 0.71 0.22 6.15 10.0 12.0 10
Dorsal side row dikinetids number 19.5 20.0 1.18 0.37 6.05 18.0 21.0 10
Buccal membranelles number 8.5 8.5 0.55 0.22 6.45 8.0 9.0 10
Kinetids number in the small ventral row 10.6 11.0 0.55 0.24 5.17 10.0 11.0 10
Macronucleus size, pm 14.6 15.0 1,58 0.50 10.81 12.0 16.0 10
Fig. 6. 1 — Strobilidium caudatum (Fromentel, 1870): 1 — general view; 2-3 — Limnostrombidium viride (Stein, 1867): 2 — ventral view, 3 — dorsal view.
short cilia (2-3 ^m). Above, an extrusome girdle with a small gap in the middle of the ventral part surrounding the body. A short ventral row composed of 10-12 dikinetids extends from this gap to the caudal end. Posterior half of the body covered by polygonal plates, probably used for fixation, easily identified by silver nitrate impregnation.
Contractile vacuole was not detected. Endo-plasm transparent with multiple zoochlorellae.
Macronucleus spherical with nucleoli. Single micronucleus adjoining macronucleus.
The species differs from available descriptions of L. viride from fresh waters of Austria (Foissner, Berger, Schaumburg, 1999) by smaller number of collar membranelles (10-11 versus 15-16) and larger number ofbuccal membranelles (12-15 versus 8-10).
Character X M SD SE CV Min Max n
Body length, pm 52.8 51.5 5.09 1.61 45.0 60.0 10
Body width, pm 44.1 45.0 3.07 0.97 6.96 40.0 48.0 10
Collar membranelles number 10.7 11.0 0.48 0.15 4.51 10.0 11.0 10
Buccal membranelles number 13.3 13.5 1.06 0.33 7.96 12.0 15.0 10
Macronucleus diameter, pm 14.9 15.0 1.52 0.48 10.23 12.0 15.0 10
Number of micronuclei 1.0 1.0 0 0 0 1.0 1.0 10
Ventral dikinetids number in each short row 11.2 11.5 0.919 0.291 8.205 10.0 12.0 10
Circumferential ciliary rows number 67.1 68.0 2.73 0.86 4.06 62.0 70.0 10
Strobilidium caudatum (Fromentel, 1870) (Fig. 6, 1; Plate 4, 6; Table 16)
It is a known freshwater species, first time found in Lake Baikal waters by Gajewskaja (Gajewskaja, 1933). We met it both among over-growths of aquatic plants and in plankton in the littoral zone of the southern basin of Lake Baikal. Below we give a short morphological description of S. caudatum in vivo and in preparations impregnated by protar-gol.
Cells 51-70x45-55 ^m in size in livespecimens and 43-55x37-45 ^m after fixation. Cone-like body shape broad in front and narrowed posteriorly. Ring composed of 26-32 adoral membranelles in the anterior body area so that 6 of them elongated
as buccal membranelles to the narrow 18-20 ^m long pharynx. Elements of the adoral membranelles composed of close one to another three rows of kinetosomes each. 6 somatic rows of small kinetosomes with 2 ^m short cilia, along the body longitudinal axis in an anterior third of the body. Stable 6 kineties, 3 of them stretched up to the caudal body end along a spiral and other 3 broken off not reaching it, in contradiction with the literature description (Foissner et al., 1991), where number of somatic rows varied from 5 to 7. The somatic rows positioned on low cortical ledges (ridges) slightly elevated over the body surface in live specimens.
Transparent cytoplasm comprising a few cells of small diatom algae. Horseshoe-like macronucleus 3-5 ^m wide with numerous nucleols, positioned in
Table 16. Biometric characteristics of Strobilidium caudatum (Fromentel, 1870).
Character X M SD SE CV Min Max n
Body length, pm 48.88 48.90 4.89 1.55 10.01 43.0 55.0 10
Body width, pm 40.10 40.0 2.92 0.92 7.29 37.0 45.0 10
Adoral membranelles number 28.70 28.0 1.77 0.56 6.16 26.0 32.0 10
Somatic kineties number 6.0 6.0 0 0 0 6.0 6.0 10
Macronucleus length, pm 19.1 19.0 0.876 0.277 4.586 18.0 20.0 10
Macronucleus width, pm 3.90 4.0 0.57 0.18 14.56 3.0 5.0 10
Micronucleus length, pm 3.50 3.50 0.53 0.17 15.06 3.0 4.0 10
Micronucleus width, pm 1.55 1.50 0.44 0.14 28.26 1.0 2.0 10
Pharynx length, pm 19.2 19.0 0.79 0.25 4.11 18.0 20.0 10
the diametrical body plane under the ring of adoral membranelles. One oval micronucleus 3-4 ^m long and 1 to 2 ^m wide.
Contractile vacuole laterally positioned in a rear quarter of the body. Swift jump-like motion with alternate soar and slow rotation.
Baikalian specimens of S. caudatum differ from those described in the literature mainly by smaller sizes and stable number, 6, of somatic rows.
Condylostoma longicaudata Alekperov, Obolkina et Wilbert sp. n. (Fig. 7, 2-4; Plate 5, 2-4; Table 17)
Diagnosis. Large light-grey ciliates about 600 ^m in size in vivo with a distinct tail about a third of the body length and triangular buccal cavity 13% of the body length. 80-115 adoral membranelles; one frontal cirrus; 40-45 somatic rows. Macronucleus beaded with 8-15 fragments. Up to 2—7 contractile vacuoles connected by single collecting canal
positioned along the left body side. Freshwater habitat.
Type location. Middle- and fine-grained sands at water depths of 2-3 m in the bay Bol’shiye Koty, the southern basin of Lake Baikal.
Type slides. One holotype (slide number Baikal 2008 N5 and two paratypes (slide number Baikal 2008 N8 and slide number Baikal 2008 N9) deposited in the Limnological Institute, Siberian Branch of Russian Academy of Sciences, Irkutsk, Russia).
Etymology. The name indicates to the long caudal tail of body.
Description. Large grey ciliates with transparent cytoplasm about 550-600x70-80 ^m in size in vivo and 314-490 ^m after fixation. Narrow, elongate, cylindrical contractile body with length to width ratio about 8:1 in live specimens. The rear half of body gradually transformed into the tail. The tail exceeds a third of the body length. Buccal cavity is about 13% of the body length in live specimens and 11-15%
after impregnation. Transparent cytoplasm contains small dark inclusions and food vacuoles frequently with small Urotricha and Cyclidium. Macronucleus located on right side of cell, moniliform with 8-15 nodules. Up to 2-7 contractile vacuoles are situated to the left with a common collecting canal.
38-45 somatic rows composed of densely arranged dikinetids connected by silver line (argy-ronema). The big part of them (about two thirds) terminate at the base of tail dorso-laterally. Only 14-16 rows run up to the end of the tail. Somatic cilia about 8-10 ^m long.
Adoral zone composed of 80-115 membranelles, 18 ^m long. Paroral membrane of two thin rows with additional short third row of kinetosomes in anterior part is situated along right side of cytostome. Two frontal cirri located close to apical end of AZM and absent in some specimens. Small cilia-free space is around it.
Swims slowly with rotation counterclockwise.
Differential diagnosis. Two Condylostoma species, C. patens (O.F. Muller, 1786) and C. caudatum Lauterborn, 1908, were registered in Lake Baikal (Rossolimo, 1923; Gajewskaja, 1933). The first lacks a tail. Six species of the genus, as well as the species described above, have a distinct tail: C. remanei Spiegel, 1928, C. remanei v. oxyoura Dragesco, 1960, C. acuta Dragesco, 1960, C. enigmatica Dragesco, 1954, C. longicauda Dragesco, 1996 and C. caudatum Lauterborn, 1908 previously found in Baikal by Gaewskaja (1933). Body shape, number of nodules and form of the contractile vacuole of the latter are very similar to those of C. longicaudata. C. longicaudata differs from the morphotype described by Gajewskaja in a larger body (twice as large, 600 ^m vs. 300 ^m), longer tail and smaller buccal cavity (13% versus 20-25% ofbody length). It was collected in summer plankton by Gaewskaja, while C. longicaudata was encountered in sand. C. caudatum Lauterborn,
Character
X
M
SD
SE
CV
Min
Max
Body length, pm Body width, pm
Length of buccal cavity, pm
Number of frontal cirri
Length of macronuclear nodules, pm
Width of macronuclear nodules, pm
Number of CVP
Buccal cavity length, pm
Number of adoral membranelles
Number of macronuclear nodules
Number of somatic kineties
408.5
83.7
39.3 2.0
24.0
15.4
5.0
61.4
95.0
41.5
396
86.5
40.5 2.0
25.0
16.0
5.0
60.0
92.5
40.5
65.4
14.4
7.2 0
5.7
3.0
1.1
9.2
20.7
4.5
2.3
0
1.8
0.9
0.3
2.9
2.8
0.9
16.0
17.2
18.4 0
23.6
19.6 21.1 14.9
13.4
6.7
314
62
30.0
2.0
15.0
11.0
4.0
50.0
80.0
38.0
490
98
48.0
2.0
30.0
20.0
7.0
78.0
115.0
45.0
10
10
10
10
10
10
10
10
10
n
10
10
1908 from Rhine has smaller size (150-200 ^m vs. б00 ^m), shorter tail and larger cytostome (ca 30% vs. 13%).
C. longicaudata differes from the remaining species by smaller buccal cavity and habitat, since they are all marine species.
C. longicaudata is smaller than C. remanei Spiegel, 1928, (500-б00 vs. б00-1200 ^m), its buccal cavity smaller (13% vs. 20% of body length), cirri absent or 1 cirrus vs. 2 cirri, C. remanei, a much smaller number of adoral membranelles (80-115 vs. 85-200), contractile vacuole present.
It differs from C. remanei v. oxyoura Dragesco, 19б0 with a strongly vacuolized cytoplasm, larger number of somatic rows (38-45 vs. 27-30), smaller buccal cavity (13% vs. 20%) and larger size (400 vs. б00 ^m). C. acuta Dragesco, 19б0 is smaller (220 vs. б00 ^m), with fewer ciliary rows (14 vs. 38-45), band-like macronucleus, larger number of solid protrichocysts and no contractile vacuole.
C. enigmatica Dragesco, 1954 also exhibits marked differences in all characters with C. longicaudata: body size (990 ^m vs. б00 ^m), cytostome (30% vs. 13%), coloration (brownish-black vs. ligth-grey, transperant), band-like macronucleus, etc.
C. longicauda Dragesco, 199б is much longer than C. longicaudata (800-1б00 vs. б00 ^m) with fewer somatic rows (27 vs. 38-45), larger buccal zone (1/б vs. ca. 1/8 of body length).
Based on available descriptions of Condylostoma species (silver impregnation method), the number of the so called apical frontal cirri located to the right of the mouth, close to the distal part of the adoral zone of membranelles (AZM) has been recently considered an important taxonomic feature. For instance, C. magnum Spiegel, 1926 as well as C. longicaudata are with two apical cirri, while C. magna Bullington, 1940 generally with one cirrus.
C. longicaudata has a well defined caudal part that makes it different from other species. Moreover, it is smaller in length and width, has fewer adoral membranelles (80-115 versus 150200), much smaller buccal cavity (45 ^m versus 150 ^m) compared to C.magnum Spiegel, 1926. C. longicaudata is different from C. minutum Bullington, 1940 by a larger number of frontal cirri (+ 1) and a smaller cytostome.
WlLBERTELLA BAIKALICA ALEKPEROV, OBOLKINA,
Wilbert sp. n. (Fig. 7, 1; Plate 5, 1; Table 18)
Diagnosis. Small (in vivo 40-60x20-38 ^m), dorso-ventrally flattened ciliates. Mouth anteriorly located on the ventral side with 9-12 nematodesma around. Two perioral kineties of different lengths above the mouth, perpendicular to the longitudinal body axis.
Somatic ciliature on the ventral side includes 12, often 13 rows of different lengths, consisting of
Character X M SD SE CV Min Max n
Body length, pm 52.8 54.0 6.94
Body width, pm 28.7 30.0 6.29
Number of somatic kineties 12.8 13.0 0.42
Number of nematodesmal rods 10.7 11.0 1.160
Number of basal bodies in terminal fragment 4.2 4.0 0.42
Number of basal bodies in right equatorial fragment 8.2 8.0 0.79
Macronucleus length, pm 20.5 20.0 3.31
Macronucleus width, pm 13.8 13.5 3.19
Number of micronuclei 1.0 1.0 0
Number of CVP 2.0 2.0 0
kinetosome pairs connected by argironeme. Nine ventral kine-ties extend from below the mouth and differ in length that increases left to right. Three right marginal kineties begin on the left anterior part of the ventral side, curve around the right margin, terminating at the posterior end. There is a short equatorial fragment consisting of 7-9 kinetosomes and a small terminal fragment with 4 kinetosomes at the left side of the ventral surface, beneath three somatic rows.
Endoplasm transparent, without inclusions. Two contractile vacuoles, one on the right side of the anterior, the other — on the left side ofthe caudal part of the body.
Nuclear apparatus consists of an elongate hetermorphic macronucleus with large nucleoli and a single spherical micronucleus. Fine polygonal cells were revealed on the dorsal side of the body after silver nitrate impregnation.
Differential diagnosis. The genus Wilbertella was established by Gong and Song (2006) based on two lynchellid species that have a non-ciliated zone in the left posterior of the body owing to availability of short left kineties. Perioral kineties Y-shaped. Non-ciliated zone between right and left kinetic rows of the ventral side is absent. Wilbertella genus includes two species — Wilbertella distyla (Wilbert,
1971), a freshwater type species and a marine species, W. stricta (Deroux, 1976). Our description of W. baikalica sp. n. shows similarities with and
2.19 13.15 40.0 60.0 10
1.99 21.92 20.0 38.0 10
0.13 3.29 12.0 13.0 10
0.37 10.84 9.0 12.0 10
0.13 10.05 4.0 5.0 10
0.25 9.62 7.0 9.0 10
1.05 16.14 15.0 25.0 10
1.01 23.12 10.0 18.0 10
0 0 2.0 1.0 10
0 0 2.0 2.0 10
differences from both species. All three species are non-ciliated in the left postoral part of the ventral surface that is considered a generic character (Gong and Song, 2006). W. baikalica is larger in size (40-60 ^m versus 20-30 ^m) than the freshwater W. distyla (Wilbert, 1971), lacks right equatorial fragment, two ventral protuberances, short row parallel to preoral kineties, and has a short terminal fragment absent in W. distyla. Besides being a freshwater species, W. baikalica differs from the marine W. stricta (Deroux, 1976) in larger size (20-30x40-60 ^m) of the complete lower preoral kinety, and one less ventral row on the anterior end.
Movement extremely slow.
Found on the aggregations of algae in the littoral zone of Southern Baikal.
References
Alekperov I. 1992. New modification of protar-gol methods to the impregnation of ciliates. Zool. J. 71, 130-133.
Alekperov I. 1993. Free living ciliates in the soils of Saint-Petersburg parks. Zoosystematica Rossica.
1, 11-28.
Alekperov I. 2005. Atlas of free-living ciliates (class Kinetofragminophora, Colpodea, Oligo-hymenophora, Polyhymenophora). “Borçali ” NPM, Baku.
Al-Raseid Kh. A.S. 2000. Some marine interstitial Prostomatida and Haptorida (Ciliata) from the Jubai Marine Wildlife Sanctuary on the Saudi Arabian Gulf shore. Fauna of Arabia. 18, 5-22.
Burkovsky I. 1970. The ciliates of the meso-psammon ofthe Kandalaksha Gulf (White Sea). II. Acta Protozool. 8, 47-65.
Chatton E. and Lwoff A. 1930. Impregnation, par diffusion argentique de l’ infraciliature des ciliés marins et d’eaudouce, apres fixationcytologique et sans dessication. C. R. Soc. Biol. 104, 834-836.
Cheisin E.M. 1928. Vorlaufiger Mitteilung über einige parasitische Infusorien des Baikalsee. Rep. USSR Acad. Sci. 295-299.
Cheisin E.M. 1930. Morphologische und Systematische Studien über Astomata aus dem Baikalsee. Arch. Protistenkunde. 70, 531-618.
Cheisin E.M. 1931. Infusorien Ancistridae und Boveridae aus dem Baikalsee. Arch. Protistenkunde. 73, 280-304.
Dragesco J. 1960. Les Ciliés mésopsammiques littoraux (systématique, morphologie, écologie). Trav. Station Biol. Roscoff., nov. ser. 12, 1-356.
Dragesco J. 1970. Ciliés libres du Cameroun. Annls Fac. Sci. Yaoundé. (Hors série). 1-141.
Dragesco J. and Dragesco-Kerneis A. 1986. Ciliés libres de l’Afrique intertropicale. Paris. 1-559.
Didier P. and Wilbert N. 1981. Sur un Cyclidium glaucoma de la Region de Bonn. (RFA) Arch. Protistenkd. 126, 96-102.
Fauré-Fremiet E. 1950. Écologie des Ciliés psammophiles littoraux. Bull. Biol. France et Belg. 84, 35-75.
Fernandez-Leborans G. and Alekperov I. 1996. Revision of the genus Zosterodasys (Protozoa, Ciliophora) with a description of a new species. Zoosyst. Rossica, St.-Petersburg, Russia. 4, 4-16.
Foissner W. 1984. Morphologie und Infracilia-tur einiger limnicher Ciliaten (Protozoa: Cilio-phora). Schweiz. Z. Hydrol. 46, 210-223.
Foissner W., Berger H., Schaumburg J. 1999. Identification and ecology of limnetic plankton Ciliates. Informationsberichte des Bayer. Landsamtes für Wasserwirtschaft. 3, 1-793.
Gajewskaja N. S. 1927. Zur Kenntnis der Infusorien des Baikalsees. Dokl. Akad. Nauk SSSR. 19,313-318.
Gajewskaja N. S. 1928. Sur quelques infusories pélagiques nouveaux du lac Baïkal. Dokl. Akad. Nauk SSSR. 23, 476-478.
Gajewskaja N. S. 1933. Zur Oecologie, Morphologie und Systematik der Infusorien des Baikalsees. Zoologica, Stuttgart. 32, 1-298.
Grolière C.-A. 1977. Contribution a l’étude des
ciliés des sphaignes et des étendues d’eau acides. I. Descryption de quelques species de gymnostomes, hypostomes, hymenostomes et heterotriches. Ann. Stat. Besse-en-Chandesse. 10, 265-296.
Hiller S. and Bardele Ch.F. 1988. Prorodon aklitolophon n. spec. and the “dorsal brush” as a character to identify certain subgroups in the genus Prorodon. Arch. Protistenkd. 136, 213-236.
Jankowski A.W. 1973. Infusoria Subclass Chonotricha. Fauna of the USSR, Leningrad, Nauka (in Russian).
Jankowski A.W. 1982a. Symbiotic ciliates of Baikal fauna. Modern problems of protozoology: Proceedings ofthe III Congress ofAll-Union society of protozoologists. Vilnius. p. 409 (in Russian).
Jankowski A.W. 1982b. New genera ofsymbiotic protozoa of Baikal fauna. Modern problems of protozoology: Proceedings of the III Congress of All-union society of protozoologists. Vilnius. p. 410 (in Russian).
Jankowski A.W. 1982c. New genera ofsymbiotic Protozoans of Baikal fauna. In: The new about Baikal fauna. Novosibirsk, Nauka. 25-32.
Jankowski A.W. 1986. New and little known genera of ciliated protozoa (Phylum Ciliophora). Trudy Zoolog. Inst., Leningrad. 144, 72-88.
Long H., Song W., Gong J., Hu X., Ma H., Zhu M. and Wang M. 2005. Frontonia lynni n. sp., a new marine ciliate (Protozoa, Ciliophora, Hymenostomatida) from Qingdao, China. Zootaxa. 1003, 57-64.
Long H., Liu H., et al. 2008. Two new ciliates from Hong Kong coastal water: Orthodonella sinica n. sp. and Apokeronopsis wrighti n. sp. (Protozoa: Ciliophora). J. Eukar. Microbiol. 55, 321-330.
Obolkina L.A. 1991. Morphology of several species of ciliates from Baikal Lake. In: Fauna Baikalia. Novosibirsk, Nauka pp. 182-250 (in Russian).
Obolkina L.A. 1995. New species of the family Colepidae (Prostomatida, Ciliophora) from Lake Baikal. Zool. Zh. 74, 3-19.
Petz W. and Foissner W. 1992. Morphology and morphogenesis of Strobilidium caudatum (Fromentel), Meseres corlissi N. Sp., Halteria grandinella (Müller), and Strombidium rehwaldi N. Sp., and a proposed phylogenetic system for Oligotrich Ciliates (Protozoa, Ciliophora). J. Eukar. Microbiol. 39, 159-176.
Puytorac P. (de) et al. 1974. Proposition d'une classification du phylum Ciliophora Doflein, 1901 (réunion de Systématique, Clermont-Ferrand). C. R. Acad.Sci. Paris. 278, 2799-2802.
Rossolimo L.L. 1923. To the protozoa fauna of Lake Baikal. Rus. Hydrobiol. J. 2, 74-82.
Rossolimo L.L. 1926. Parasitische Infusorien aus dem Baikal-See. Arch. Protistenk. 54, 469-509.
Song W. and Wilbert N. 1989. Taxonomische Untersuchungen an Aufwuchsciliaten (Protozoa, Ciliophora) im Poppelsdorfer Weiher, Bonn. Lauterbornia. 3, 2-221.
Swarczewsky B. 1928a. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. I. Dendrosomidae. Arch. Protistenk. 61, 349-378.
Swarczewsky B. 1928b. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. II. Dendrocometidae. Arch. Protistenk. 62, 41-79.
Swarczewsky B. 1928c. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. III. Discophryidae. Arch. Protistenk. 63, 1-17.
Swarczewsky B. 1928d. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgamma-
riden lebenden Infusorien. IV. Acinetidae. Arch. Protistenk. 63, 362-409.
Swarczewsky B. 1928e. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. V. Spirochonina. Arch. Protistenk. 64, 44-60.
Swarczewsky B. 1929. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. YI. Stentorina. Arch. Protistenk. 1929.65,38-44.
Swarczewsky B. 1930. Zur Kenntnis der Baikalprotistenfauna. Die an den Baikalgammariden lebenden Infusorien. VII. Lagenophrys, Vaginicola und Cothurnia. Arch. Protistenk. 69, 455-532.
Wilbert N., 1975. Eine verbesserte Technik der Protargolimprägnation für Ciliaten. Mikrokosmos. 64, 171-179.
Address for correspondence: Ilham Alekperov. Laboratory of Protistology, Institute of Zoology, Azerbaijan National Academy of Sciences, Baku, 370073, e-mail: [email protected]
