Myxobolus platanus n. sp. (Myxosporea, Myxobolidae), a parasite of Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae) from Lagoa dos Patos, RS, Brazil

Myxobolus platanus n. sp. infecting the spleen of Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae) from Lagoa dos Patos, Brazil is described The parasites formed round or slightly oval whitish plasmodia (about 0.05-0.1mm in diameter) on the surface of the organ. The spores were round in frontal view and oval in lateral view, 10.7µm (10-11) long, 10.8µm (10-11) wide and 5µm thick, and presented four sutural marks along the sutural edge. The polar capsules, equal in size, were prominent, surpassing the mid-length of the spore, and were oval with the posterior extremity rounded, and converging with their anteriorly tapered ends. They were 7.7µm (7-8) long and 3.8µm (3.5-4) wide. A small intercapsular appendix was present. The polar filament formed five to six coils obliquely placed to the axis of the polar capsule. No mucous envelope or distinct iodinophilous vacuole were found.

Thelohanellus habibpuri sp. n. (Myxozoa: Bivalvulida) from the tropical freshwater fish rohu, Labeo rohita (Hamilton-Buchanan, 1882) in West Bengal, India: Light and electron microscope observations

A new species of myxozoan (Myxozoa: Bivalvulida) Thelohanellus habibpuri sp. n. parasitic in tropical freshwater fish collected from the Habibpur, West Bengal, India is described in this paper. T. habibpuri was found in the Pectoral fin of Labeo rohita (Hamilton-Buchanan, 1882). The diagnostic characters of T. habibpuri are: generally oval milky-whitish plasmodia attached in the pectoral fin of host fishes; spore egg-shaped to ovoid with slightly tapering anterior and rounded posterior end, averaging 13.9 × 8.5 μm in size; a single oval-round polar capsule 6.0 × 4.9 μm in diameter, with polar filament wound in 3-4 coils. Finely granular sporoplasm containing two slightly oval nuclei (1.4 μm in diameter) and a small iodinophilous vacuole (3.0 μm in diameter) present in the spore.SEM study of this myxozoan reveals the anterior extremity of spore is truncated. The Cnidocyst discharge channel appear as a dark area. The longitudinal wavy surface are visible on the spore.