Tenaturris janira is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.

(Original description) The small shell is brownish, with an acute brown protoconch of 4½ regularly increasing whorls (apparently smooth but slightly eroded), changed abruptly into the sculpture of the five subsequent whorls.

The axial sculpture consists of (on the body whorl 10) low rounded ribs with wider interspaces, obsolete on the base and incremental sculpture indicated by the rather distant sharp striae.

The spiral sculpture consists of (on the spire two, on the body whorl three) rather prominent nodules on the ribs with no conspicuous cord in the corresponding part of the interspaces.

The aperture in the type specimen is elongate ovate with a simple columella and a thin sharp outer lip.