Nebela is a diverse genus of testate amoebae of cosmopolitan distribution, belonging to the family Hyalospheniidae. They are "prey agglutinated" or "kleptosquamic" organisms, meaning they take the inorganic plates from their prey to construct their test.
Members of this genus have a thin, transparent, pseudochitinous, flattened test that can be ovate, pyriform or elongate, with a length of around 180 microns. The surface of the test has numerous oval or circular scales of variable size, or in rare occasions rectangular or rod-like scales. The protoplasm is granular and colorless but can contain food vacuoles that show color. They have a single nucleus and a variable number of pseudopodia that are blunt in shape. The cell body is attached to the test's interior by strands of ectoplasm.
Nebela originally belonged to the family Nebelidae, but phylogenetic analyses showed that the genus was paraphyletic and the genera Hyalosphenia and Quadrulella, which belong to Hyalospheniidae, branch within Nebela. Accordingly, the family Nebelidae was synonymised with Hyalospheniidae.
There are at least 13 remaining species in the genus:
The paraphyly of Nebela is slowly being resolved by transferring species from Nebela to other genera through phylogenetic analyses. The following species were previously considered Nebela but have been moved accordingly: