
Difflugia acutissima Deflandre, 1931
Diagnosis: Shell elongated ovoid with a short, more or less distinct neck. Fundus tapers into a sharp spine. Shell composed of quartz particles, sometimes mixed with fragments of diatom shells. Pseudostome circular.
Dimensions: Deflandre (1931): Shell length 178-233 µm; my measurements 210-265 µm (n>15).
Habitat: I have found this species in the sediments of a ditch in the nature reserve Naardermeer, the Netherlands. Some shells were compressed and exhibited a biconcave shape, which is characteristic of Difflugia biconcava, also present at the same location.
Remarks: In his description of this species, Deflandre compared its shape to a truncated cigar. It can be distinguished from Difflugia acuminata by its short, distinct neck and sharply tapering spine.
Gauthier-Lièvre and Thomas (1958) described a variety, gigas, collected in Algeria and Chad, Africa, with dimensions ranging from 260–295 µm in height and 100–190 µm in diameter. My measurements fall between those of the type and the variety.


