Taxonomical studies of four new Aseptate Gregarine parasites belonging to the Genus Monocystis Stein, 1848 (Protozoa: Apicomplexa: Sporozoa) from an Oligochaete Host, Eutyphoeus orientalis (Annelida: Oligochaeta) of West Bengal, India Author Sarkar, Sutapa Author Kundu, Beauty Author Bandyopadhyay, Probir K. text Records of the Zoological Survey of India 2019 119 4 journal volume 10.26515/rzsi/v119/i4/2019/142223 2581-8686 13185663 Monocystis satoi sp. nov. Figures 5 (A-E), 6(A-E) Table C & Table 3 Description Gamonts are elongated, flat and oval shaped. One end rounded and other cone shaped. Presence of smooth and thick ectosarc. Endosarc is vacuolated. Presence of distinct rounded nucleus at the conical portion of the gamonts. Gametocysts are rounded contains two unequal gametocytes. Oocysts are biconical having pointed ends. The gamont measures 96.55-125.00 (15.25±8.25) x 50.28-62.50(59.22±5.00) µm. Nucleus measuring 12.35-14.50(13.75±1.00) µm in diameter. Gametocyst measures 70.00-75.00(72.00±4.32) µm in diameter. Oocyst measures 15.17-18.17(16.70±1.35) in length 9.75- 11.25(10.00±1.00) µm in width. Taxonomic Summary Type host : Eutyphoeus orientalis Site of infection : Seminal vesicles Distribution : Ashoknagar, North 24 Parganas ( 23°15'2" N-89 °5'E), West Bengal , India . Prevalence : 10 out of 35 host earthworms (28.57%) were infested with the parasite. Figure 6. Monocystis satoi sp. nov. (Camera lucida drawings of different stages of life cycle) A-B. Trophozoite. C. Syzygy D. Gametocyst. E. Oocyst. Scales: A-D =100µm; E=10µm. Material deposited Holotype : PR/ MC/05 /12 has been deposited at the Parasitology Laboratory , Department of Zoology , University of Kalyani , Kalyani 741235, West Bengal , India . Paratype : The paratype has been deposited in the Harold W Manter , Laboratory of Parasitology , Systematic Research Collections , University of Nebraska State Museum, W 436, Nebraska Hall , Lincoln , Nebraska 68588-0514 USA, (Accession no. P-2014-002; Reg. no. HWML 49896 ). Etymology : The species name have been given after the name of renowned parasitologist Prof. Hiroshi Sato, Joint Faculty of Veterinary Medicine of Yamaguchi University , 1677-1 Yoshida , Yamaguchi , 753-8515, Japan for his outstanding contribution in the field of Parasitology . Remark While compairing, the present species with Monocystis nidata , Monocystis pontodrilli and Monocystis darjeelingensis , it appears that the trophozoite is flat and oval shaped having one rounded and other conical end in the present form. Whereas in M. nidata , it looks like a small cell which possess two blunt ends, but in M. pontodrilli it is elongated having two broadly rounded ends. In M. pontodrilli the trophozoite crescent shaped and mucron is present in one end of the trophozoite. On the contrary, it is also crescent shaped in the present form. Nucleus is rounded and present in conical portion of the present species. But in M. nidata and M. pontodrilli , it is ovoid, centralized and rounded present either at the anteriormiddle or the posterior end respectively. Trophozoite is cylindrical with rounded extremities of one end and slightly wider than other in M. Darjeelingensis . In M. Darjeelingensis , nucleus is spherical in shape and present in the narrow portion. Furthermore, M. darjeelingensis is much larger in all respects than the present form and earlier described other species. The oocyst is navicular in M. nidata and M.darjeelingensis respectively.While, in M.Pontodrilli it is spindle or boat shaped but biconical in the current species. Moreover, M. nidata and M. pontodrilli have been described from Pontodrilus ephippiger of Asia and Indo-China and Pontodrilus barmudensis of South India respectively whereas, M.darjeelingensis and the present species have been reported from Amynthas robusta of Senchal lake of Darjeeling and Eutyphoeus orientalis of Ashoknagar, North 24 Parganas district of West Bengal , India respectively. Table C. Summary of morphometric data of Monocystis satoi sp. nov. stages in the seminal vesicles of Eutyphoeus orientalis
Parameters Range Mean Median SD SE CV%
Length of the trophozoite 96.55-125.00 15.25 15.24 8.25 1.84 54.09
Width of the trophozoite 50.28-62.50 59.22 59.19 5.00 1.11 8.44
Diameter of the nucleus 12.35-14.50 13.75 13.27 1.00 0.22 7.27
Length of the gametocyst 70.00-75.00 72.00 72.18 4.32 0.96 6
Length of the oocyst 15.17-18.17 16.70 16.40 1.35 0.30 8.08
Width of the oocyst 9.75-11.25 10.00 10.34 1.00 0.22 10
Table 3. The morphometric comparison of Monocystis satoi sp. nov. (Present work) with some closely related species
Species character Monoystis nidata ( Boisson, 1957 ) Monocystis pontodrilli ( Subbarao et al ., 1979 ) Monocystis darjeelingensis ( Bandyopadhyay and Mitra 2005 ) Monocystis satoi sp. nov. (Present work)
Host Pontodrilus ephippiger Pontrodrilus barmudensis Amynthas robusta Eutyphoeus orientalis
Locality Asia, Indo-China South India Darjeeling, West Bengal, India Ashoknagar, North 24 Pargnas, West Bengal, India
Site of infec- tion Seminal vesicles Coelom, body muscle and Seminal vesicles Coelomic fluid Seminal vesicles
Trophozoite Small cell like, elongated length 260-290 µm and width 90-120 µm Elongated, measures 350µm x 150 µm. Cylindroid having round extremities. One end slightly wider than the other. Conical or elliptical in young stage measuring 204- 273 µm x 84-140 µm. Flat, elongated and oval shaped, measuring 96.55-125.00 (15.25 ±8.25) µm x 50.28- 62.50 (59.22± 5.00) µm in diameter.
Ectosarc Thin, smooth Thin, smooth With fine longitudinal striations Thick, smooth
Endosarc Vacuolated Vacuolated Granulated Vacuolated
Nucleus Spherical situated in the center, 50 µm in diameter Oval, position is variable Spherical 8.3-12.5 µm in diameter. Rounded with unequal gametocytes. It measures 70.00 – 75.00 (72.00 ± 4.32) in diameter.
Gametocyst Not mentioned Spherical, measures 350 µm x 160 µm in diameter. Spherical 147- 163 µm Rounded 12.35 – 14.50 (13.75 ±1.00) µm in diameter.
Oocyst Navicular, 9 µm in length Boat shaped, measur- ing 8.0 µm x 3.2 µm Navicular, 15.4-18 µm x 8.0- 9.0 µm. Biconical, measuring 15.17 –18.17(16.70±1.35) µm x 9.75– 11.25(10.00± 1.00) µm.
Taking into account all the differences with the closely related species, the present species seems to be new one. Hence the name Monocystis satoi sp. nov. is given here.