Gregarina niphandrodes (Eugregarinorida: Septatorina): oocyst surface architecture.

The surface architecture of oocysts produced by Gregarina niphandrodes (Eugregarinorida) from Tenebrio molitor adults (Coleoptera: Tenebrionidae) as revealed by scanning electron microscopy is reported. Gametocysts were allowed to dehisce on 15-mm, round cover glasses; the cover glasses with their oocysts chains were then mounted on stubs without further processing, and sputter-coated with 20-nm gold palladium. Scanning electron microscopy was performed at 10-15 kV with a Hitachi 3000N SEM. Oocysts retained their characteristic shapes as reported in the original species description but showed longitudinal ridges of relatively uniform height, width, and spacing, in separate fields on either side of a central equatorial bulge in the oocysts. There was no ultrastructural evidence of an enclosing external sheath holding the oocysts in a chain. Oocyst ends were flared slightly, and the chain itself was twisted, with adjacent oocysts offset slightly from one another. This article now provides an additional set of structural characters potentially useful in gregarine systematics.