Myxobolus mrigalhitae     (Protozoan)
Organism information awaits expert curation
Class: Myxosporea

Plasmodia: fully developed plasmodia are round in shape and attached with the gill filaments of infested host fishes. The earlier stages, uni- and binucleate pansporoblasts are not present but a few ultinucleate pansporoblasts are observed. The multinucleate pansporoblasts are irregular in shape. These have 12 nuclei, which segregate into two equal groups and form 2 sporoblasts. So the pansporoblast is disporous. The nuclei are of different shapes and nature. The capsulogenous nuclei are elongate, valvular nuclei are large and irregular and sporoplasmic nuclei appear oval.
Spores: immature spores are round to spherical in shape. Two polar capsules occupy most part of the spore cavity. Fully developed or mature spores are pyriform in front view and are 10.8 ± 0.32 (10.2-11.3) x 7.9 ± 0.18 (7.6-8.1) in dimensions. The posterior end is broad and rounded whereas the anterior end is narrow and blunt. The spore valves are thick at the posterior end, but thin at the anterior one. The sutural ridge is broad with straight median sutural line. In the posterior extremity of the spore there lie 2-5 parietal folds. The inner wall of the spore valve forms a thickening of intercapsular appendix.
Two polar capsules are unequal. The larger one is 4.8 ±0.30 (4.3-5.2) x 2.9 ± 0.16 (2.7-3.2), pyriform with broader posterior and bluntly pointed anterior ends. The smaller polar capsule is tear-shaped and 3.0 ± 0.09 (2.9-3.2) x 2.1 ± 0.06 (2.0-3.2) in measurement with slightly curved anterior end. The polar filament makes 5-6 and 3-4 spiral coils inside larger and smaller polar capsules respectively. Polar filament from the larger polar capsule extrudes through the anterior end of the spore but that from the smaller one extrudes through the anterolateral end, i.e., there lie two separate openings for the extrusion of two polar filaments.
The sporoplasm is granular, homogenous and fills the extracapsular space. Two karyosomatic sporoplasmic nuclei of 1.1 ± 0.08 (1.0-1.2) diameter and a spherical glycogen containing iodinophilous vacuole having a diameter of 3.0 ± 0.09 (2.9-3.3) are present in the posterior part of the sporoplasm.
Spore index:
LS: WS = 1: 0.731
LLPC: WLPC = 1: 0.604
LSPC: WSPC = 1: 0.7
LLPC: LSPC = 1: 0.625
WLPC: WSPC = 1: 0.724
Intraspecific variability: Spore with slightly acuminate anterior end and larger polar capsule with 7-8 turns of polar filament were noticed in very few forms.

Type host: hybrid between Mrigal (Cirrhinus mrigala) and Rohu (Labeo rohita) carp.
Prevalence and intensity of infection: 241/372 (64.72%).

Remarks: All measurements are presented in micrometers as mean ± SD followed in parentheses by the range.

Synonym (s)

Common Name (s)
Economic Importance and Threats



• West Bengal, Kalna INDIA (Record: 2003)

Literature Source(s)
  • Basu, S and Haldar, DP (2003) Three new species of Myxobolus Butschli, 1882 from different food fishes of West Bengal, India Acta Protozoologica 42 245 - 251 Available at -
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

Page last updated on:2009-11-20

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