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Myxobolus dhanachandi sp. n. (Myxozoa, Myxospo-rea, Bivalvulida) from an Indian freshwater fish Channa orientalis (Bloch-Schneider)
Probir K. Bandyopadhyay 1, Th. Hemananda 2, Amlan Kumar Mitra 1 and N. Mohilal 2
1 Parasitology Laboratory, Department of Zoology, University of Kalyani, West Bengal, India
2 Parasitology Laboratory, Life Sciences Department, Manipur University, Canchipur, Imphal, India
Summary
Investigations on the incidence of myxozoans in fishes have assumed immense importance because of severe pathogenicity of these parasites and host mortality associated with them. The present communication describes a new myxosporean species, Myxobolus dhanachandi sp. n., from a freshwater fish Channa orientalis (Bloch -Schneider) from the state of Manipur, India.
Key words: Myxozoa, Myxobolus dhanachandi sp. n., parasite, fish, India
Introduction
The genus Myxobolus was established by O. Bütschli (1882). Since that time, approximately 500 species of Myxobolus have been reported from freshwater and marine fishes (Landsberg and Lom, 1991). A biotic survey of protozoan parasites in fishes from ponds of Kangla Fort (Manipur, Imphal, India) revealed a new Myxobolus species. The present communication deals with the description of the new species in accordance with the guidelines of Lom and Arthur (1989) and Lom and Dykova (1992).
Material and Methods
Host fishes were collected alive from the pond of Kangla Fort, brought to the laboratory and examined immediately. Sporogonic plasmodia, when found, were carefully removed with sterile forceps, smeared on clean grease-free slides with drops of 0.5% NaCl solution, covered with cover slips and sealed with bee wax for examination under the oil immersion lens of Olympus CH-2 phase contrast microscope. Some of the fresh smears were treated with various concentrations (210%) of KOH solution for the extrusion of polar
© 2007 by Russia, Protistology
354 • Probir K. Bandyopadhyay et al.
6 7 8
Figs 1-9. Camera lucida drawing of the spore of M. dhanachandi sp. n. 1 - Immature spore; 2, 3 - spore in fresh condition; 4, 5 - spore stain with Lugol's Iodine; 6 - spore in sutural view; 7 - immature spore stained with Geimsa; 8 - spore stained with Geimsa (unextruded polar filament); 9 - spore with extruded polar filament (Geimsa). Scale bar: 10 |im.
filaments. The Indian ink method of Lom and Vavra (1963) was employed for observing the mucous envelope of spores. For permanent preparations, air-dried smears were stained with Giemsa after fixation in acetone-free absolute methanol. Measurements (based on twenty fresh spores treated with Lugol's iodine) were done with the aid of a calibrated ocular micrometer. All measurements are presented in ^m as mean ± SD followed in parentheses by the range. Drawings were made on fresh or stained material with the aid of a mirror type camera lucida and the Corel Draw 10.0 computer programme.
The abbreviations used in the paper are as follows: LS - length of the spore; WS - width of spore; LLPC - length of large polar capsule; WLPC - width of large polar capsule; LSPC - length of small polar capsule; WSPC - width of small polar capsule; LPC - length of polar capsule; WPC - width of polar capsule; LPF - length of polar filament; DIV -diameter of iodinophilous vacuole.
Results and Discussion
Myxobolus dhanachandi sp. n. (Figs 1-10).
Plasmodia. Pinkish-white spherical plasmodia, 0.27 mm in diameter, are found attached to the dorsal, ventral and caudal fins. They contain mostly matured spores, some late stage spores were also present.
Spores. The spores are small, elongated, dumb-bell shaped, broader at the middle and tapering at both ends. In sutural view, the spore is lenticular, with a slightly curved broad sutural line. The two shell valves are narrow, smooth and symmetrical. In immature forms the spores have broader middle part, and the polar capsules are shorter and thicker.
Mature spores measure 17.0-19.5 (18.4 ± 1.01) ^m in length and 5.1-6.8 (6.05 ± 0.62) ^m in breadth. In fresh condition there is variation in spore structure in respect to the position of the polar capsules.
There are two polar capsules of equal size. Both are elongated and tear-shaped with a sharply pointed anterior end and a slightly rounded posterior end. Polar capsules are situated almost parallel to each other. They measure 7.7-8.5 (8.26 ± 0.36) ^m in length and 0.81.7 (1.43 ± 0.41) ^m in breadth. The polar capsules occupy almost half of the total spore body. In Giemsa-stained slides, the polar capsules are somewhat posterior in position. The two polar filaments are extruded from two separate openings. They measure 27.2-34.0 (29.49 ± 3.64) ^m in length.
The extracapsular space is occupied by granular homogenous mass of sporoplasm. A iodinophilus
vacuole, 0.8-1.7 (0.97 ± 0.42) ^m in diameter, and two or three very small sporoplasmic nuclei are present in the sporoplasm. In some of the spores, there is a rounded structure adjacent to the inner wall.
The present species resembles M. angustus Kudo, 1934 reported from gill filaments of Cliola vigilax (Kudo, 1934); M. calbasuiChakravarty, 1939 reported from the gall bladder of Labeo rohita (Hamilton) and Cirrhinus mrigala (Hamilton) (Chakravarty, 1939); M. punctatus Roychaudhuri and Chakravarty 1970 from spleen and pharyngeal epithelium of Ophicephalus punctatus (Bloch) (Roychaudhuri and Chakravarty, 1970); M. vedavantiensis Seenapa and Manohar, 1981 from gills and muscles of Cirrhinus mrigala (Hamilton) (Seenapa and Manohar, 1981); M. bhadhuria (Sarkar, 1985) Gupta and Khera, 1988 from gills and fins of Puntius sarana (Hamilton) (Gupta and Khera, 1988) and M. iranicus Molnar, Masoumain et Abasi, 1996 from the spleen of Barbus luteus (Heckel) (Molnar et al., 1996); M. catlae Chakravarty, 1943 from fins and gills of Cirrhinus mrigala (Hamilton) (Chakravarty, 1943) and M. koi Kudo, 1919 from gill filaments of Cyprinus carpio haematopterus (Kudo, 1919).
However, M. angustus (LS: 14-15; WS: 7-8), M. calbasui (LS: 12.4-15; WS: 8.2-10; LLPC: 6.1; WLPC: 4.1; LSPC: 4.1; WSPC: 3.0), M. vedavatienses(LS: 1315; WS: 8-10 ; LLPC: 6.9-7.5; WLPC: 3-4; LSPC: 3-
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Fig. 10. Photomicrograph of spores of Myxobolus dhanachandi sp.n. stained with Giemsa. Scale bar:
12 |im.
5; WSPC: 2-3), M. iranicus(LS: 13.2-14; WS: 7.5-9.2; LLPC: 6.9-7.5; WLPC: 2.9-3.5; LSPC: 6.6-7.2) differ from the present species (Table 1) in morphometric characteristics.
M.punctatus(LS: 12.2-15; WS: 85.7-7.8; LPC: 8.510; WPC: 2.1-2.8), M. bhaduria (LS: 10-14; WS: 5-8; LPC: 5-7; WPC: 2-4), M. catlae (LS: 14-15; WS: 5; LPC: 10; WPC: 2-2.5; LPF: 30-41) have polar capsules similar in size to the present species but differ from it in other morphometric characteristics and spore shape.
Finally, M. koi (LS: 14.0-16.0; WS: 7.0-9.0; LPC: 7.0-9.0.p; WPC: 2.7) is morphometrically similar to our species. However, the former has elongated, tearshaped spores, and the latter, the dump-bell shaped spores.
In view of these differences, the myxozoan under study should be considered as a new species. Hereby, we name it Myxobolus dhanachandi sp. n.
Table 1. Statistical analysis of measurements and ratios of Myxobolus dhanachandi sp. n.
Measurement Range X SD SE CV%
LS 17.0 - 19.5 18.4 1.01 0.22 5.48
BS 5.1 - 6.8 6.1 0.62 0.13 10.24
LPC 7.7 - 8.5 8.3 0.36 0.08 4.35
BPC 0.8 - 1.7 1.4 0.41 0.09 28.67
DIV 0.8 - 1.7 0.9 0.42 0.09 43.29
LPF 27.2 - 34 29.5 3.64 0.81 12.34
LS : WS = 1 : 0.3288 LPC : WPC = 1 : 0.1731 LS : LPC = 1 : 0.4489 WS : WPC = 1 : 0.2363
Abbreviations: see Materials and Methods
Taxonomic summary
Type host: Channa orientalis (Bloch-Schneider).
Type locality: Kangla, Manipur.
Type specimens: One holotype, slide C0/04/2003, and paratypes, slides C0/01/2003, C0/06/2003, CO/ 08/2003, Collection of the Life Science Department, Manipur University, India.
Prevalence and Intensity of Infection: 08/10 (80%).
Etymology: The specific epithet dhanachandi has been given after the name of late Prof. Ch. Dhanachand of Life Sciences Department, Manipur University, for his outstanding contribution to parasitology.
Acknowledgments
The authors are grateful to Prof. B. Manihar Sharma (Head of the Life Sciences Department, Manipur University) for providing the laboratory facilities and to Dr. W. Vishwanath Singh (Department of Life Sciences, Manipur University) for identifying the host species. Sincere thanks are also due to Hav. H. Ashakumar Singh (1st IRB. Kangla Manipur) for participation in the material collection. The Indian Ministry ofEnvironment and Forest is acknowledged for financial assistance in the form of an All India Co-ordinated Project on Taxonomy.
References
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Address for correspondence: Probir K. Bandyopadhyay. Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India. E-mail: [email protected]
Editorial responsibility: Andrew Dobrovolskij
