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Protistology 4 (3), 207-211 (2006)
Protistology
Dirhynchocystis indica (Apicomplexa, Rhyncho-cystinae), a new gregarine species from the earthworm Lampito mauritii (Annelida, Oligochaeta) in India
Probir K. Bandyopadhyay and Amlan Kumar Mitra
Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani, West Bengal, India
Summary
Dirhynchocystis indica, a new gregarine species from the earthworm Lampito mauritii (Annelida, Oligochaeta) from West Bengal, India, is described. Mature trophozoit has an elliptical body with two unequal elongate trunks, one at each pole. The short trunk has a rounded apex, and the long trunk is bluntly pointed. Gametocyst is spheroidal. Nucleus is spheroidal to ellipsoidal in shape, situated generally near one of the poles. Oocysts biconical.
Key words: gregarines, acephaline, earthworm, Dirhynchocystis indica sp. n., India
Introduction
Gregarines are chiefly coelozoic or lumen-dwelling protozoans of invertebrates, especially arthropods and annelids. Of the two major groups ofgregarines, aseptate and septate, earthworms harbour the aseptate forms. The aseptate, or acephaline forms are characterized by a non-septate body. Aseptate gregarine fauna has been reported from various parts of the world including India. However, especially in India, the search is far from complete, although work on this particular group has gained momentum since 1980 (Bandyopadhyay et al.
2001, 2004, 2006a, 2006b, 2006c; Pradhan and Dasgupta, 1983a, 1983b; Roychoudhury and Haldar, 1984; Bandyopadhyay and Mitra, 2004, 2005a, 2005b, 2005c, 2005d). Further study of aseptate gregarines from Indian earthworms reveals a new species of the genus Dirhynchocystis Cognetti de Martiis 1921 (Martiis, 1921). Levine (1988) listed seven species under the genus Dirhynchocystis, only one of them described from India (Bhatia and Chatterjee, 1925). In this paper, taxonomic descriptions of a new species of genus Dirhynchocystis, as well as comparisons with closely related species, are given.
© 2006 by Russia, Protistology
208
Probir K. Bandyopadhyay and Amlan Kumar Mitra
Material and Methods
Earthworms were collected and taken to the laboratory. They were dissected while alive and their seminal vesicles were carefully removed and placed on clean glass with a drop of 0.5 % NaCl solution. A thin film of the seminal fluid was drawn out on a slide covered with a cover slip for examination of live protozoans under a phase contrast microscope. The content of seminal vesicles was semidried and fixed in Schaudin's fluid (20 min). The fixed smears were stored in 70 % ethyl alcohol for removal of mercuric chloride. The slides were then passed through a descending alcohol series (5 min each) and stored in distilled water. They were transferred to a 3% iron alum solution and stained with Heidenhain's haematoxylin solution (20 min). Differentiation (overnight) was done with 1 % iron alum solution. The slides were then washed thoroughly, dehydrated in an ascending alcohol series, cleared in xylene and mounted in Canada balsam. Photographs were taken with an Olympus camera. All measurements in this article are in micrometers. For each measurement, minimum and maximum values are given, followed in parentheses by arithmetic mean and standard deviation.
Results
Phylum: Apicomplexa Levine 1977
Order: Eugregarinida Leger 1900
Family: Monocystidae Bütschli 1882
Subfamily: Rhynchocystinae Levine 1977
Dirhynchocystis indica sp. n. (Figs 1-6; Tables 1 , 2).
With the characters of the genus Dirhynchocystis Cognetti de Martiis 1921 (Martiis, 1921) as given by Levine (1988): gamonts metabolic, most often elongated into a conical or cylindroconical trunk, gamont with projections at both ends; oocysts biconical, in seminal vesicles and rarely coelom of Oligochaetes (Levine, 1988). The mature gamont has an elliptical body with two elongate trunks, one at each pole. The trunks are very unequal in length and parallel to the longitudinal axis of the body. The apex of the short trunk is rounded but that of the long trunk is bluntly pointed. The long trunk sometimes looks slightly angular, which might be due to distortion during smear preparation. The measurement ofbody length is taken as the distance between the bases of the two trunk-like appendages, and the measurement of width is taken at a right angle to this axis where the width is maximum. Ectoplasm is thin but prominent, about 1.0-1.5 ^m thick all over the body except in the appendages. Endoplasm is granular and packed with homogenous granules. These granules
are restricted mostly to the trophozoite body but sometimes they are seen to invade the basal portion of the long trunk due to streaming movement of the endo-plasm. The nucleus is spheroidal to ellipsoidal, situated within the body of the gamont, generally near one of the poles. Karyosome is diffused. Gametocyst is almost spheroidal. Oocysts biconical.
Measurements of gamonts and different body proportions are presented in Table 1.
Type material: Dirhynchocystis indica sp. n.
Type host: Lampito mauritii
Symbiotype: Host LM - 04/2003 deposited in the Museum of the Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
Site of infection: Seminal vesicles.
Type locality: Dimond Harbour, South 24 Parganas, W. Bengal, (Lat. 22.11°N, Lon. 88.14 °E).
Prevalence: 04 out of 19 (21.05%).
Type material: Holotype, slide DA/01/2003, and Paratypes, slides DA/02/2003, DA/03/2003 and DA/ 04/2003 are in the collection of the Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
Etymology: The specific epithet 'indica" has been derived from the name of our country.
Discussion
Being a parasite of earthworms seminal vesicle and in having ellipsoidal body with two cylindro-conical trunk-like appendages coming off the body, the parasite justifies its inclusion under the family Monocystidae, subfamily Rhynchocystinae and the genus Dirhynchocystis Cognetti de Martiis 1921 (Martiis, 1921). Seven Dirhynchocystis species have been described from all over the world. Only one of them, Dirhynchocystis globosa, is known from India. It was reported by Bhatia and Chatterjee (1925) from Lahore (now in Pakistan), Bombay and Lucknow. In D. globosa the body is globular and the long trunk is shorter than the body, whereas in the present form the body is ellipsoid and the long trunk is always longer than the body. In both species the trunks are unequal in size.
D. brasiliensis has an ovoid body, with equal trunks placed at an angle of about 130° to the body. The present form differs from this species in having a more elongate body and unequal trunks at the opposite poles. D. oblongata also possesses ovoid body with unequal trunks, like the present form, but differs in having a smaller nucleus and the trunks ending in rounded tips. D. minuta has a sub-spherical body and unequal trunks with rounded tips. But the present form has a larger body, and the ratio of large trunk and small trunk is 3:2 whereas the present form has a different type of
Figs 1-3. Photomicrographs of different stages of life cycle of Dirhynchocystis indica sp. n. 1 - a mature trophozoite; 2 - a gametocyst; 3 - oocysts. Scale bars: 1, 2 - 100 pm, 3 - 10 pm.
Table 1. Summary of measurements (pm) of different body parts and ratios of 32 gamonts of Dirhynchocystis indica sp. n. obtained from Amynthas robusta.
Figs 4-6. Camera lucida drawings of different stages of life cycle of Dirhynchocystis indica sp. n. 4 - a mature trophozoite; 5 - a gametocyst; 6 - oocyst. Scale bars: 1, 2 - 100 pm, 3 -10 pm.
Different body parts Mean Range Standard deviation
Body length (BL) 62.5 48.4-88.0 1.8
Body width (BW) 33.4 22.0-48.4 2.6
Nucleus length (NL) 19.3 13.2-22.0 1.1
Nucleus width (NW) 13.6 6.6-17.6 2.8
Short trunk length (STrL) 21.0 13.2-57.2 1.9
Long trunk length (LTrL) 77.8 26.34-132.0 2.2
Short trunk Width (STrW) 5.9 3.3-8.8 1.7
Long trunk Width (LTrW) 7.8 3.3-13.2 3.1
BL/BW 1.9 1.6-2.5 2.4
NL/NW 1.5 1.0-2.5 1.9
BL/STrL 3.4 1.1-4.0 1.8
BL/LTrl 0.9 0.5-2.3 2.6
LTrL/STrL 4.2 1.5-7.3 3.5
BL/NL 3.3 2.6-4.4 1.8
Table 2. Comparisons between different characters of Dirhynchocystis indica sp. n. with closely related species (all measurements are in pm).
Species Characters D. brasiliensis Cognetti de Martiis 1921 D. globosa (Bhatia and Chatterjee 1925) Bhatia 1929 D. minuta Ruston 1959 D. oblonga Tuzet and Loubatiers 1946 D. indica sp. n.
Host(s) Fimoscolex inurus Pheretima heterochaeta and Eutyphoeus sp. Lumbricus terrestris Octolasium complanatum Lampito mauritii (Kingberg)
Locality Brazil Pakistan and India England France India
Trophozoite Ovoid Globular Subspherical Ovoid Ellipsoid
Length 45-55 74.0 35.5 50.0 48.4-88.0 (62.5±1.8)
Width 55-80 65.0 31.2 75.0 22.0-48.4 (33.4±2.6)
Appendages (mucron) Equal: round at tip Nearly equal: short and spine-like Unequal: round at tip Unequal: round at end Unequal: short arm round and long arm nearly pointed at tip
Length 1 (L 1) 25 — 43.4 — 13.2-57.2 (21.0±1.9)
Length 2 (L 2) 25 — 29.6 — 26.4-132.0 (77.8±2.2)
L1: L2 1:1 — 3:2 — 1: 4.2±1.6
Nucleus Nearly round Ovoid, monokaryosomic - - Ovoid
Size 12 in diameter 24 in longer diameter 4.5 6-8 13.2-22.0 (19.3±1.1) by 6.6-17.6 (13.6±2.8)
NDorNL: BL 1: 4.2 1:3.1 1:7.8 1: 7.1 1:3.3±0.5
Angle of appendages to body 130° - 115° - 180°
Gametocyst - - - - Spheroidal
Size - - - - 65.0-88.0 (72.0±1.9)
Oocyst - - - - Biconical
Size - - - - 7.8-11.3 (9.1 ±2.1)
Refernce Martis (1921) Bhatia (1929) Ruston (1959) Tuzet and Loubatiers (1946) Present study
210 • Probir K. Bandyopadhyay and Amlan Kumar Mitra
attachment of the trunks to its body and the ratio of the length of long trunk: short trunk is 4.2:1.
After careful consideration the present form cannot be accommodated into any known species ofthe genus Dirhynchocystis. Therefore, a separate species has been proposed for the present form. It is designated as Dirhynchocystis indica sp. n. A comparison between D. indica and other closely related species is presented in Table 2.
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: prabir0432@hotmail.com
Editorial responsibility: Andrew Dobrovolskij
