Difflugia globulosa, 94 µm

 

 

Difflugia globulosa (Dujardin, 1837) Penard, 1902

 

Diagnosis: shell brown, spherical or hemispherical, usually composed of large quartz particles but may also include diatom frustules; general appearance rough, although some smoother forms have been seen; aperture circular and surrounded by smaller particles which often appear smooth due to the overlaying cement; variation in this species is prolific, both in the composition of the shell and the size of the aperture in relation to the diameter of the shell.

 

Dimensions: literature: diameter of shell 91-155 µm

 

Ecology: peatbogs, between wet sphagnum; oligotrophic ponds.

 

Remarks: Shells of this species can be confused with those of Phryganella nidulus which are more flattened.
Penard (1902) describes this species as having two distinct forms, the typical form and one varying between 135 and 155 µm. He also described two smaller forms 50 to 70 µm in size. Cash et al. (1909) describe a small form (15-50 µm) under the name D. globulus, and suggest that Dujardin's original description of D. globulosa was ambiguous.

 

Difflugia globulosa, 133 µm
Difflugia globulosa, 122 µm
Difflugia globulosa
Original drawings of Penard (1902) in Faune Rhizopodique du Bassin du Léman.
Difflugia globulosa, 122 µm