Amlan Kumar Mitra

Studies on Trichodinid and Chilodonellid Ciliophorans (Protozoa: Ciliophora) in the Indian freshwater and estuarine fishes with description of Trichodinella sunderbanensis sp nov and Trichodina nandusi sp nov.

A comprehensive icthyoparasotological survey among estuarine and freshwater fishes of West Bengal, India revealed Trichodinella sunderbanensis sp. nov. and Trichodina acuta Lom, 1961 from an estuarine fish Mystus gulio (Hamilton, 1822) from the Vidyadhari river; Trichodina nandusi sp. nov. from a freshwater fish, Nandus nandus (Hamilton-Buchanan); Chilodonella hexasticha (Kiernik, 1909) Kahl, 1931 from freshwater fishes Labeo rohita (Hamilton, 1822); and Cyprinus carpio Linnaeus, 1758 from the Rupnarayan river. Taxonomic description of all the species based on wet silver nitrate impregnation method along with additional comments based on scanning electron microscopic descriptions of T. nandusi sp. nov. are also provided in this paper. Prevalence rate, morphometric parameters and comparisons with closely related species are also discussed.

Observations on two new species of Monocystis Stein, 1848 (Protozoa: Apicomplexa: Monocystidae) Monocystis darjeelingensis sp.n. and M. ranaghatensis sp.n. from earthworms (Annelida: Oligochaeta) of West Bengal, India

Surveys of acephaline gregarines infesting earthworms from Senchal of Darjeeling and Ranaghat of Nadia districts of West Bengal, India revealed the occurrence of two new species of Monocystis Stein, 1848. Monocystis darjeelingensis sp.n. was found in the coelomic fluid of the earthworm Amynthus robusta Perrier, 1892 from Senchal, Darjeeling, and M. ranaghatensis sp.n. in the seminal vesicles of the earthworm Eutyphoeus valtoni (Michaelsen) from Ranaghat. Trophozoites of M. darjeelingensis sp.n. are cylindroid in shape: 210.0-273.0 (231.0 ± 2.0) × 84.0-140.0 (98.0 ± 1.8) μm; spherical gametocyst: 147.0-163.0 (156.0 ± 0.4) μm; navicular oocyst: 15.4-18.0 (17.0 ± 1.0) × 8.0-9.0 (8.2 ± 0.5) μm. Trophozoites of M. ranaghatensis sp.n. are napiform, having a nearly spheroid to ellipsoid or ovoid body, 119.0-167.0 (124.0 ± 11.0) × 57.0-84.0 (62.0 ± 1.9) μm with a prominent tail like structure at the posterior end and ellipsoidal nucleus, 9.022.0 (12.0 ± 0.4) × 9.0-13.0 (10.0 ± 1.5) μm. Gametocysts are egg-shaped, measuring 95.0-124.0 (105.0 ± 0.9) μm. Oocysts are biconical, measuring 7.6-10.1 ( 9.3 ± 1.1) × 4.1-5.6 (4.5 ± 1.3) μm.

Observations on two new species of Nematocystis Hessé, 1909 (Protozoa: Monocystidae) from earthworms (Annelida: Oligochaeta) of West Bengal, India

Surveys of acephaline gregarines from Nadia district (23°N, 88.5°E) of West Bengal, India revealed the occurrence of two new species of Nematocystis Hesse, 1909; Nematocystis gardenica sp.n. and Nematocystis kalyaniensis sp. n. in the seminal vesicles of earthworms, Amynthas diffriengens (Bairds, 1809) and Amynthas hawayanus (Rosa, 1891), respectively. Trophozoites of Nematocystis gardenica sp. n. are elongate, nematode-like and have parallel sides with pointed tips. Dimensions of trophozoites ranged from 110 to 1320 (505.0 ± 12.0) μm. Dimensions of gametocysts ranged from 140 to 166 μm and the small biconical sporocysts have varying dimensions of 11.0−12.6 μm × 4.0 μm. Trophozoites of Nematocystis kalyaniensis sp.n. are solitary, elongate, nematode-like but have nearly equal bulb-like swellings at two ends, one of which lodges the nucleus. Dimension of trophozoites ranged from 246 to 1232 (565.0 ± 21.0) μm. Dimensions of gametocysts ranged from 120 to 155 μm. Sporocysts are biconical with dimensions of 8.5−11.4 × 5.0 μm.

First record of ectoparasitic African Trichodinids (Ciliophora: Peritrichida) in a cichlid fish Oreochromis mossambicus (Peters 1852) from the Churni river system, West Bengal, India

Oreochromis mossambicus (Peters 1852) and Oreochromis niloticus niloticus Linnaeus, 1758 are two popular freshwater fishes introduced from Africa to India. There are many records of different species of trichodinid ectoparasites infesting wild and cultured cichlids in Africa, but no such study has been conducted on this parasitic group in India. The fishes Oreochromis mossambicus and Oreochromis niloticus niloticus were investigated for the occurrence of trichodinid ciliophorans. Oreochromis mossambicus was found positive for two species, viz., Trichodina centrostrigeata Basson, Van As & Paperna, 1983 and Paratrichodina africana Kazubski & El-Tantawy, 1986. Oreochromis niloticus niloticus was found not to be infested with any species of trichodinid ciliophorans, although, interestingly, Paratrichodina africana was first discovered in this host fish. Comparative descriptions and prevalence of these two above-mentioned species are presented.

Myxobolus leafa sp. nov. (Myxozoa: Bivalbulida) from the gill filament of Labeo bata (Hamilton) from Manipur, India.

OBJECTIVE The aim of this study was to investigate the gill filaments of Labeo bata in India parasitologically and to describe the new Myxozoa parasite species, Myxobolus leafa sp. nov., which was determined. METHODS Fish were collected alive from fish farms from Manipur (India). Sporogonic plasmodia were removed with sterile forceps and observed under phase contrast microscope. For permanent preparations, air dried smears were stained with Giemsa after fixation in acetone free absolute methanol. RESULTS Mature spores of the new species appear as leaf-like structures in valvular or frontal view, tapering at both ends. The anterior end of the spore is broader than the posterior end. Spores measure 15.3-11.8 μm (16.91 ± 1.16) in length and 13.6-15.3 μm (14.15 ± 0.67) in breadth. CONCLUSION The new gill parasite species, Myxobolus leafa sp. nov., was described from fish in India. The prevalence of the parasite was 3.3% and two stages (cyst and spore) of the parasite existed in its life cycle.