Presence of Marteilia sp. (Paramyxea) in the razor clam Solen marginatus (Pennántt, 1777) in Galicia (NW Spain).

Protistan parasites of the genus Marteilia, phylum Paramyxea, cause the molluscs disease named Marteiliosis. Histological observations and transmission electron microscopy revealed the presence of life cycle stages of a Marteilia sp. in the bivalve mollusc Solen marginatus (Solenidae). Parasites occurred in epithelial cells of the digestive ducts and tubules. Early stages (primary cells) presented one or several nuclei while advances stages formed a complex of cells-within-cells (secondary and tertiary cells) culminating in spores. Refringent bodies were present inside the presporangia. This is the first report of a Marteilia sp. in S. marginatus.