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Protistology 6 (1), 14—18 (2009)
Protistology
Gymnocyclidium nabranicum gen. et sp. nov. (Gymnocyclidiidae fam. nov.) (Scuticociliatida, Ciliophora), a new freshwater ciliate from NorthEastern Azerbaijan
Ilham Kh. Alekperov
Institute of Zoology, Azerbaijan National Academy of Sciences, Baku
Summary
Freshwater ciliate fauna of North-Eastern Azerbaijan was studied in 2003—2006. A new scuticociliatid species, Gymnocyclidium nabranicum gen. et sp. nov., is described. The newly established family Gymnocyclidiidae clearly differs from the other Scuticociliatida by reduction of bipolar somatic kineties to two or three short longitudinal crowns. It comprises three monotypic genera: the type genus Gymnocyclidium gen. nov., the genus Paurotricha Dragesco et Dragesco-Kerneis, 1991 and the genus Paracyclidium Groliere, de Puytorac, Grain, 1980.
Key words. Gymnocyclidium nabranicum gen. et sp. nov., Scuticociliatida, Gymnocyclidiidae fam. nov., freshwater ciliates, systematics, ciliate fauna of Azerbaijan
Introduction
In spite oflong-term research, free-living ciliates of Azerbaijan are still insufficiently studied. First of all, this concerns the North-Eastern Azerbaijan, a region with numerous clean small rivers and springs. There are no investigations of its freshwater ciliate fauna, except one general hydrobiological research, which mentioned, alongside with other groups of hydrobionts, 9 ciliates species (Veysig, 1940).
Free-living ciliate fauna of North-Eastern Azerbaijan was studied in 2003—2006. The present paper reports a new freshwater scuticociliatid ciliate from this region.
Material and methods
Freshwater ciliates were sampled in several small rivers and springs of North-Eastern Azerbaijan, mainly near Russian state border. Altogether, 140 samples of plankton, periphyton and benthos were collected and processed. The ciliates were caught by microcapillars and studied both in vivo and after silver nitrate (Chatton and Lwoff, 1930) and protargol (Alekperov, 1992) impregnation. Impregnated cells were drawn using a camera lucida. Cell length and width were measured both on living and impregnated ciliates. All measurements were made on not less than 10 specimens. The type material
© 2009 by Russia, Protistology
E F
Fig. 1. Members of the Gymnocyclidiidae fam. nov. (representatives of the three monotypic genera). A-B — Gymnocyclidium nabranicum gen. et sp. nov.; C-D — Paurotricha cyclidiformis Dragesco et Dragesco-Kerneis, 1991 (according to Dragesco and Dragesco-Kerneis, 1991); E-F - Paracyclidium rhabdotectum (Powers, 1935) Groliere, de Puytorac, Grain, 1980 (according to Groliere, de Puytorac, Grain, 1980). Abbreviations: UM -undulating membrane, M1, M2, M3 - oral membranelles, Ct - cytostome, S - scutica, CC - caudal cilia, AR - anterior somatic crown, PR - posterior somatic crown, CR - caudal somatic crown, Lcs - lateral ciliary scarf, Ma - macronucleus, Mi - micronucleus. Scale bars: A-B - 20 ^m, C-F - 10 ^m.
was deposited with the collection of the laboratory of Protistology in the Institute of Zoology of NAS of Azerbaijan, Baku.
Morphometric data are based on randomly selected, protargol impregnated and mounted nondividers. Statistics was performed using the program SigmaStat 2.0.
Results
Family Gymnocyclidiidae fam. nov. (Fig. 1).
Diagnosis. Free-living (freshwater species) or endocommensals of sea urchins (marine species). Buccal infraciliature typical of the Scuticociliatida Small, 1967.
Somatic ciliature reduced to a longer apical crown bearing double kinetosomes and a shorter posterior crown or crowns bearing simple kineto-somes; their is one posterior crown in Paurotricha and Paracyclidium and two posterior crowns in Gymnocyclidium. Anterior crown separated from posterior crown or crowns by a wide non-ciliated equatorial area. Two caudal cilia and two post-oral scutica present.
Gymnocyclidiidae fam. nov. comprises three monotypic genera: the type genus Gymnocyclidium gen. nov., Paurotricha Dragesco et Dragesco-Ker-neis, 1991 (Dragesco and Dragesco-Kerneis, 1991) and Paracyclidium Groliere, de Puytorac, Grain, 1980. The former two genera are free-living, while the latter is endocommensal of sea urchins (Groliere et al., 1980).
The newly established family Gymnocyclidii-dae clearly differs from the other representatives of Scuticociliatida Small, 1967 by strong reduction of somatic ciliature.
Genus Gymnocyclidium gen. nov.
Diagnosis. Freshwater. Ciliates of middle size (in vivo 55—70 ^m x 35—40 ^m) with buccal ciliature typical of Scuticociliatida: undulating membrane and three oral membranelles (Mp M2, M3). Outline oval, with truncated anterior and posterior poles. Somatic ciliature reduced to three ciliary crowns of different width; a longer anterior one consisting of dikinetids, a shorter posterior one consisting of simple kinetosomes and the caudal one consisting of a single kinetosome. There are two caudal cilia and two post-oral scutica.
Type species Gymnocyclidium nabranicum gen. et sp. nov.
Fig. 2. Gymnocyclidium nabranicum gen. et sp. nov. (protargol impregnation). A — ventral side, B — dorsal side. Scale bar: 20 ^m
Comparison with related genera. Gymnocyclidium gen. nov. resembles the genus Paurotricha: both have the outline with truncated anterior and posterior poles, double kinetosomes in the anterior crown and single kinetosomes in the posterior one. However, Gymnocyclidium is clearly different from Paurotricha. First, it lacks the characteristic oblique ciliary scarf of the latter. Second, it has three crowns of somatic ciliature, while Paurotricha has two crowns.
The new genus differs from the genus Paracy-clidium in the number of somatic ciliature crowns — three instead of two, and the arrangement and structure of oral membranelles — it has longer coneshaped membranelles M2 and a wider non-ciliated equatorial area. The ecology of these two genera is also different: Gymnocyclidium comprises free-living freshwater ciliates, while Paracyclidium, marine endocommensals of sea urchins.
Gymnocyclidium nabranicum gen. et sp. nov. (Figs 1 A, B; 2)
Diagnosis. Outline oval, with truncated anterior and posterior poles. Somatic ciliature reduced to three ciliary crowns of different width. The anterior crown consisting of 17—20 rows of dikinetids, with
16—18 dikenetids in a row. The posterior crown consisting of17—18 rows, with 7—8 simple kinetosomes in a row. The caudal crown consisting of a single kinetosome. Two caudal cilia and two post-oral scutica present.
Type location. Sandy bottom of a shallow spring near Nabran village.
Type specimens. One holotype as a slide (N—2) of protargol impregnated cells.
Table 1. Morphometric characteristics of Gymnocyclidium nabranicum gen. et sp. nov.
Character X M SD SE CV Min Max n
Body length 48.7 48.0 3.401 1.075 6.984 45.0 55.0 10
Body width 26.6 26.5 2.951 0.933 11.094 22.0 30.0 10
Adoral membranelle M1 length 43.0 4.50 0.823 0.260 1.914 3.0 5.0 10
Adoral membranelle M2 length 7.791 7.90 0.336 0.101 4.313 7.0 8.10 11
Adoral membranelle M3 length 3.460 3.50 0.259 0.0819 7.486 3.10 4.0 10
Undulating (paroral) membrane length 31.6 33.0 3.658 1.157 11.576 27.0 35.0 10
Number of somatic
kineties in the anterior 18.5 18.0 1.179 0.373 6.373 17.0 20.0 10
crown
Number of somatic
kineties in the posterior 17.5 17.5 0.527 0.167 3.400 17.0 18.0 10
crown
Number of somatic
kineties in the caudal 17.750 18.0 0.463 0.164 2.608 17.0 18.0 8
crown
Caudal cilia number 2.0 2.0 0 0 0 2.0 2.0 10
Postoral scutica number 2.4 2.0 0.516 0.163 21.5 2.0 3.0 10
Number of kinetosomes
(dikinetids) in each row of 16.9 17.0 0.738 0.233 4.367 16.0 18.0 10
anterior crown
Number of kinetosomes
in each row of posterior 7.5 7.5 0.527 0.167 7.027 7.0 8.0 10
crown
Number of kinetosomes number in caudal crown 1.0 1.0 0 0 0 1.0 1.0 10
Macronucleus length 12.420 12.5 0.377 0.119 3.035 12.0 13.0 10
Macronucleus width 7.540 7.5 0.331 0.105 4.390 7.0 8.0 10
Micronucleus diameter 2.850 3.0 0.435 0.138 15.263 2.0 3.5 10
Abbreviations: X — arithmetic mean, M — median, SD — standart deviation, SE — standart error, CV— coefficient of variance (in %), Max — maximum, Min — minimum, n — number of specimens.
Description. Living cells 55—70 ^m x 35—40 ^m, cells after fixation 45—55 ^m x 22—30 ^m. Body shape oval, with truncated anterior and posterior ends. Buccal infraciliature typical of the
Scuticociliatida: large buccal area includes, on the left, 3 adoral membranelles: M1 — a double row of 10-11 dikinetids, M2 — a more voluminous conelike membranelle of 21—24 kinetosomes and M3 — a
double row of 5—6 dikinetids. On the right, there is an enclosing paroral undulating membrane, with double kinetosomes joined in a zigzag pattern. A fine cytostome is located at the upper left margin of the undulating membrane. Below the undulating membrane, there are 2 or 3 post-oral scutica. Somatic ciliature is composed of three ciliary crowns of different width. The anterior crown consists of
17—2О rows of dikinetids, with 16-18 dikenetids in a row. The posterior crown consists of17—18 rows, with 7—8 simple kinetosomes in a row. The caudal crown consists of a single kinetosome. Two caudal cilia are present at the caudal end. There is a wide non-ciliated zone between anterior and posterior crowns.
Endoplasm transparent, with dark spherical inclusions in the anterior part. Usually there are 3—7 food vacuoles with bacteria. Macronucleus oval to spherical (13 ^m), with a single micronucleus (2—3,5 ^m), located usually in mid body or anterior part. Contractile vacuole located posteriorly. Cyto-proct unknown (not seen in protargol impregnated slides).
References
Alekperov I.Kh. 1992. New modification of impregnation ciliates kinetome by silver proteinate. Zool. Zh. (Moscow). 2, 130-133 (in Russian with English summary).
Chatton E. and Lwoff A. 1930. Impregnation, par diffusion argentique, de l’infraciliature des cilifts marins et d’eau douce, apms fixation cytologique et sans dessication. C. R. Soc. Biol. Paris. 104, 834-836.
Dragesco J. and Dragesco-Kerneis A. 1991. Free-living Ciliates from the coastal area of lake Tanganyika (Africa). Eur. J. Protistol. 26, 216235.
Groliere C-A., Puytorac P. and Grain J. 1980. Observations de quelques espnces de cilies en-docommensaux d’echinides du golfed u Mexique et de la mer des Antilles. Protistologica. 16, (2), 233-239.
Veysig S.Ya. 1940. Materials for microscopic hydrofauna of Caucasus and its zoogeographical analysis. PhD thesis, Baku, 1-336.
Address for correspondence: Ilham Alekperov. Laboratory of Protistology, Institute of Zoology, Azerbaijan National Academy of Sciences, Baku, 370073, e-mail: i_alekperov@yahoo.com
