Diagnosis. Very small, skeneid-like gastropods with smooth protoconch, apically keeled first teleoconch whorl, and intraumbilical keel. Tentacles united by skin-fold across very small snout; with sensory papillae. Mouth small, cruciform. Radula absent.
Etymology. Mikros (Greek), small.
Remarks. The genus Levella MARWICK, 1943 (type species L. tersa MARWICK, 1943) from Lower Miocene deposits in New Zealand) has some resemblance in the indistinct keel on the most apical whorl, but lacks the intraumbilical rib and has strong spiral cords on the protoconch.
Species of Lissotesta have some resemblance to those in Mikro in the shape of the shell and the umbilicus. The former, however, have a very distinctive protoconch with no whorls visible externally and they have a seguenziid type radula (WAREN 1992).
Mikro becomes another genus to add to the long list of 'skencid' genera of uncertain position among the so-called archaeogastropods. Its position in Archaeogastropoda is, however, well founded by the presence of sensory papillae on the tentacles.