Bayerotrochus tangaroanus, or Tangaroan slit shell, is a species of sea snail, a marine gastropod mollusc in the family Pleurotomariidae.

[1] The shell has a typical trochoid shape with a spire angle of approximately 90 degrees and nearly straight sided profile until the later whorls which are slightly rounded with an oblique periphery and a clearly defined suture.

The aperture is oval, the slit is positioned roughly halfway between the periphery and the suture and is relatively short, about 16 percent of the circumference.

The shell is lightly sculptured with fine spiral threads which are more clearly defined below the selenizone (the area where the shell growth filled in the slit) crossed by stronger axial growth lines which gives the effect of a weak rectangular pattern.

The protoconch and primary whorls are white and are smooth, the rest of the shell is creamy peach to white, or pale pink, with a slight iridescent sheen and occasional sparse pale reddish axial flammules.