Monocystis clubae, Bandyopadhyay, Probir K., Mitra, Amlan Kumar & Mallik, Partha, 2006

Bandyopadhyay, Probir K., Mitra, Amlan Kumar & Mallik, Partha, 2006, Biology of Monocystis clubae sp. nov. (Apicomplexa: Eugregarinida) from an Indian earthworm Lampito mauritii (Annelida: Oligochaeta) of India, Zootaxa 1120, pp. 51-55 : 52-54

Monocystis clubae sp. nov. ( Figs. 1–4 )

Gamont Length (GL): 104.0­179.0 (160.0±24.5, 28); Gamont Width (GW): 62.5.0–71.0 (64.0±6.5, 28); Tail Length (TL): 33.0–45.0 (41.0±3.0, 28); Tail Width (TW): 8.0–11.0 (9.0±0.2, 28); Nucleus Length (NL): 12.0–24.0 (20.0±4.0, 28); Nucleus Width (NW): 4.0–16.0 (11.0±4.0, 28); Gametocyst Length (GL): 88.0–107.0 (104.0±1.3, 28); Gametocyst Width (GW): 86.0–102.0 (96.0±1.9, 28); Oocyst Length (OL): 9.6–11.0 (10.4±0., 28); Oocyst Width (OW): 7.3–8.0 (7.6±0.2, 28); GL:GW= 2.0:1.0; GL:TL= 3.9:1; GW:TW= 7.1:1; GL:NL= 8:1; GW:NW=5.8:1; OL:OW= 1.3:1. (28= sample size)

Members of the genus Monocystis Stein, 1848 are characterized by having no distinct mucron, ovoid and solitary gamonts, biconical, symmetrical oocysts ( Levine, 1988). In case of acephaline gegarine forms obtained from the seminal vesicles of the earthworm Lampito mauritii from Nadia district of West Bengal, gamonts appear club­shaped with a gradually tapering pointed tail. Ectoplasm is thin, 2.0–4.0 µm in thickness. Epicyte is very fine and is free from surface striation. Endoplasm vacuolated with few densely granulated structures, which are randomly distributed. Number of granules is less in the narrow part in comparison to wider portion. Nucleus elongated and in most cases irregular in shape, length is twice its width and its outer surface is rough. In most cases, length of nucleus is twice its width. Nucleus located roughly at the middle or in wider portion of mature gamont. Gametocyst rounded to slightly ovoid. There are two unequal gametes in the gametocyst. The oocysts are navicular in shape.

Taxonomic summary

Type material: Monocystis clubae sp. nov.

Type host: Lampito mauritii

Symbiotype: Host LM/ 07/2005, LM/11/2005 deposited in the Museum of the Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.

Site of infection: Seminal vesicles.

Type locality: Kalyani (23°E, 88.5°W), Nadia, India

Prevalance: 11 out of 28 (39 %).

Type material

Holotype: (Accession no. ZSI/2437) are in the collection of the Museum of the Zoological Survey of India (ZSI), Calcutta ­ 700016.

Paratypes: Slides MC/04/2005, MC/06/2005, NG/07/2005 are in the collection of the Parasitology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.

Etymology: This species is named “ clubae ” since the structure of the gamont is club like.

Discussion

Cylindroid, solitary, without mucron, late syzygy and coelomic habitat of the parasite in an earthworm justify the inclusion of the present form under the family Monocystidae , subfamily Monocystinae and genus Monocystis Stein, 1848 . Of more than 70 species belonging to the genus Monocystis Stein, 1848 ( Levine 1988) only 11 have been described from India. Of these 11 species, M. odontotermi Kalavati, 1979 has been reported from the haemocoel of the termite Odontotermes obesus (a non oligochaete host) and M. pontodrilus Subbarao, Kalavati and Narasimhamurti, 1979 from the littoral oligochaete, Pontodrilus bermudensis. All other nine species of Monocystis have been reported from terrestrial earthworms, but none from the present host Lampito mauritii . The species under discussion closely resembles Monocystis megascolexae Kar, 1946 and M. ranaghatensis Bandyopadhyay and Mitra, 2005 in having a tail­like protrusion at the posterior end of the body. In both M. megascolexae and M. ranaghatensis the anterior end of the gamont is rounded and the other end is pointed. In the new species, the anterior end is club­like with a tail­like protrusion at the posterior end. The anterior end of the gamont of M. ranaghatensis contains a bulb­like structure, which is absent in the new species. Moreover, the size of the gamonts of M. megascolexae is much larger (135.8–429.0 x 58.2–97.5) than the present species obtained from L. mauritii . Endoplasm of the gamonts of M. megascolexae is highly granular, but that of the new species is vacuolated with few black granules. The size of the gamonts, gametocysts and oocysts of M. ranaghatensis do not vary significantly when compared with those of M. clubae sp. nov., but the total morphology is totally different. Moreover, endoplasm of gamonts of M. ranaghatensis is densely granular, but that of M. clubae sp. nov. is vacuolar. Oocysts of M. megascolexae is spindle­shaped, which is navicular in M. clubae sp. nov. Based upon morphology and morphometrics, no other species belonging to the genus Monocystis Stein, 1848 resembles the new species. After a thorough comparison, the present species is being considered as a new and is designated as Monocystis clubae sp. nov. in this paper.

Figures

FIGURES 1 – 4. Photomicrographs of different stages of life cycle of Monocystis clubae sp. nov. Figs. 1 – 2. Mature gamonts; Fig. 3. Gametocyst; Fig. 4 Oocyst. Scale bars 100 µm (Figs. 1 – 2); 10 µm (Fig. 3).