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.
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 Hessé, 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.
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.
West Bengal, situated in the eastern part of the country, is one of the most beautiful and important states of India. In a developing country like India, fish is one of the cheapest sources of protein and West Bengal contributes a major portion of the total fish production. Fishery development represents a vital sector in West Bengal. The degree of success in this sector depends to a great extent on the advancement of fish parasitology research, as it is evident that the increase of fish yields can only be achieved from healthy fish stock. During an investigation (July 2001 - December 2002), a protozoan ectoparasite, Chilodonella hexasticha (Kiernik, 1909) Kahl, 1931, was found on the gills of a freshwater fish Nandus nandus (Hamilton). This finding is very important for the fishery sector, as this parasite causes the disease chilodonellosis, which leads to mass mortality. The present paper deals with the morphology, systematics, seasonal incidences and prevalence of C. hexasticha.
A new species of the genus Thelohanellus Kudo, 1933 is described from the gills of Labeo rohita. Thelohanellus anilae sp. n. occurs in two morphometrically dissimilar forms which are described as microspore and macrospore of the same species.