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

Plasmodia: Round, creamy white in color, developed within the gill lamellae of infested host fishes. They contain a large number of mature spores only.
Spores: The mature spores are light yellowish in color. Spores are 6.6 ± 0.32 (6.1-7.1) x 6.2 ± 0.21 (5.7-6.5), almost spherical in front or valvular view and broadly lenticular in sutural view with symmetrical shell valves of uniform thickness. Both the ends of the spores are rounded, but the anterior part of the spore is bulged out to accommodate the polar capsules. Sutural ridge is median and straight. Two polar capsules are equal [4.2 ± 0.22 (3.8-4.5) x 2.3 ± 0.21 (2.0-2.7)] in size and pyriform in shape with rounded posterior ends and cover anterior 2/3rd of the spore cavity. Anterior tip of the capsule is pointed in most of the forms. Polar filament is thick and makes 4-5 loose spiral coils inside each capsule. The intercapsular ridge or appendix is absent. The posterior 1/3rd of the spore cavity is filled with finely granular, homogenous mass of sporoplasm, which extends slightly into the intercapsular space. Two very small dot-like compact sporoplasmic nuclei of 0.8 ± 0.11(0.6-0.9) diameter are situated centrally. These are transversely parallel or oblique in position. Iodinophilous vacuole and mucus envelope around spores are absent.
Spore index:
LS: WS = 1: 0.939
LP: WP = 1: 0.548
LS: LP = 1: 0.636
WS: WP = 1: 0.371
Intraspecific variability: The anterior end in a few spores is slightly pointed. Anterior extremity of two polar capsules is almost fused in some forms. A few spores with coarse sporoplasmic granules are also common in some subpopulation.

Host: Lates calcarifer (fish).
Prevalence and intensity of infection: 67/385 (17.40 %).

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, North 24 Parganas, Naihati 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 -

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