[2] The etymology of the specific epithet sororculus, little sister, was proposed as a reference to its former placement with the species M. fraterculus, derived from Latin to mean little brother.

The brown fur colour is dark and rich in tone, with longer and slightly silky hair over the upper parts.

The tragus of Miniopterus sororculus is distinguished from sister taxa by its relatively long and curved form, extending 6 to 8 mm from the thickened base to its tip.

In addition to the patagium of the wings, species of Miniopterus possess a uropatagium at the lower limbs, these membranes are a very dark and almost uniform brown colour.

[2] The species is categorised as least concern by the IUCN red list, which notes their wide distribution across the Malagasy highlands and habitat coinciding with anthropogenic disturbance.