Fig. 4 in A new Myxobolus (Cnidaria: Myxosporea) infecting the ornamental catfish Corydoras schwartzi from the Purus River in Brazil

Fig. 4 (next page). Electron micrographs of myxospores of Myxobolus adrianoi sp. nov., parasite of the intestine of Corydoras schwartzi Rössel, 1963. A. Young sporoblast showing polar filament still out of the polar capsules, abundant valve-forming material, conspicuous sutural line (large white arrow), some sporoplasmosomes (small white arrows), mitochondria and presence of pinocytic channels (white arrowheads) in the ectoplasm. B–C. Sporoblast in advanced developmental stage with polar filament (white arrows) inside the polar capsule. In B note several sporoplasmosomes (white arrows) and two nuclei at sporoplasms. In C observe presence of valve-forming material (short white arrows), capsulogenic cell, nuclei at sporoplasm and nucleus of capsulogenic cell. D. Immature myxospore showing valvogenic cells abutting each other to form a sutural ridge and showing the two cells are separated by a thin layer of homogenous material (white arrow). E–F. Almost mature myxospores showing sutural lines (black arrows), valve-forming material (*), valves, two nuclei and sporoplasmosomes (white arrows) at sporoplasms. Abbreviations: cp = capsulogenic cell; ec = ectoplasm; mt = mitochondrion; nc = nucleus of capsulogenic cell; Nu = nucleus; pc = polar capsule; PF = polar filament; sp = sporoplasm; v = valvogenic cell/valve; vm = valve-forming material. Scale bars: 2 μm.