Longinebela penardiana  (Deflandre, 1936)
Basionym: Nebela penardiana Deflandre, 1936

Diagnosis: Shell usually brownish, pyriform or elongate, slightly laterally compressed, with small lateral margins that do not extend around the aboral region. Small lateral pores are typically present at about one‑third of the body length from the aperture. The shell is composed of a mixture of oval, circular, and quadrangular shell plates. The aperture is oval, sometimes concave in lateral view, and surrounded by a collar of organic cement.

Dimensions: According to Kosakyan et al. (2025), the size of the test varies by author:
Length 115–175 μm; width 65–80 μm; pseudostome ovoid in frontal view, slightly curved in broad view, surrounded by a thin organic collar rim; pseudostome 23–35 μm wide.
My measurements: Length 118–197 µm.

Remarks: This species is distinguished from P. marginata by being narrower and having less pronounced lateral margins, and from L. tubulosa and G. galeata by differences in size and shape. Deflandre (1936) noted one variety of L. penardiana in his review of the genus. For distinguishing characters from L. ampulla, see that description.