From Lüftenegger et al, 1988

 

 

Trinema penardi  Thomas & Chardez, 1958

 

Diagnosis: Shell composed of two independent parts. Outer component carries the circular shell platelets, inner part forms the oval aperture. In contrast to the very similar T. galeata, the inner shell does not form an anterior apertural rim.

Thomas and Chardez (1958) give a size of 42-55 x 20-30 x 14-20 µm, and a major axis of the aperture of 10-15 µm. Lüftenegger et al. (1988) found a wider range, for example length 30-65 µm.