Bullinularia navicula Thomas, 1959
Diagnosis: Test ovoid, transversely elongated, with regular contour because of smooth covering with limited number of xenosomes. Pseudostome approximately centrally situated, dorsal lip arc-shaped and ventral lip (“tongue”) penetrating deeply into the cavity of the test. Test hyaline, colorless or slightly yellowish. No pores visible light microscopically.
Dimensions: Length mean 87 µm, width mean 51 µm (n=7)
Ecology: tropical forest soils (Angola, Ivory Coast, Nepal, Venezuela)
Remarks: B. navicula is distinguished by its very regular elliptical and very elongated form, its almost central pseudostome and its generally colorless transparent covering.