Difflugia scalpellum
 
Difflugia cf scalpellum (from China, length 212-242 µm)

 

 

Difflugia scalpellum Penard, 1899

 

Diagnosis: Shell bilateral symmetrical, cylindrical, gradually swelling from the aperture for about two-thirds of the body length to the broadest diameter and then tapering in the last third of the body length to a bluntly or sharply, asymmetrically shaped apex. Test composed of quartz particles and diatom frustules, giving it the appearance of a regular smooth surface. Aperture usually circular. Nucleus vesicular with central nucleolus.

 

Dimensions: Penard: length mean 220-300 µm; my measurements: 212-242 µm.

 

Ecology: in oligotrophic and mesotrophic ponds, between sphagnum; rare.

 

Remarks: this species was described and pictured by Ogden as Difflugia venusta Penard 1902, but his photomicrographs are quite different from Penards drawing and description.

 

Difflugia scalpellum
These shells were prepared by Penard and labeled as "Difflugia scalpellum" (image from Mazei and Warren, 1912).

 

Difflugia scalpellum
D. calpellum", Pénard Collection, Geneva - Photograph by Thierry Arnet, as part of the Pénard project. The red color is borax-carmine.
Difflugia scalpellum
 
Difflugia scalpellum (from Penard, 1902)

 

Difflugia scalpellum
From China

 

 

Difflugia scalpellum

 

I have identified these shells as D. smilion, but the drawing to the left is from Penard and shows D. scalpellum.