Light and electron microscopic descriptions of Sphaerospora coregoni El-Matbouli, Hoffmann and Kern, 1995 (Myxosporea: Sphaerosporidae) from the kidney of Whitefish ( Coregonus lavaretus)

Abstract

Summary Sphaerospora coregoni El-Matbouli, Hoffmann and Kern, 1995 is described from the kidney of Coregonus lavaretus obtained from lake Constance and two other Bavarian lakes. Out of 80 fish (ranging in size from 25–35 cm and 200–250 g) twelve were found to be infected. The spores and pseudoplasmodia occurred in the lumen of the kidney tubules and inside the Bowman's capsules. The earliest pseudoplasmodia contained a primary cell and two secondary cells. All pseudoplasmodia were proved to be disporoblastic. Early pseudoplasmodia containing 12 cells were surrounded by a primary cell which was amorphous, rounded and measured 13.6 ± 0.8 μm in diameter. Spores in suturai view are prominent showing small protrusions at the anterior and the posterior end. Length of the spores was 8,2 μm (7.6 ± 8.6 μm) and their width including the lateral valves' thickness 11.3 μm (10.5 ± 12.4 μm). The two spherical polar capsules measure 1.9 μm (1.9 ± 2.0 μm). There were no apparent effects on the tubules during the sporogenic phase. However, infected renal corpuscles showed some dilatation of glomerular capillaries and Bowman's space. Data on ultrastructure and sporogenesis are presented.