Octomarginula ostheimerae is a species of small sea snail, a marine gastropod mollusk in the family Fissurellidae, the keyhole limpets and slit limpets.

[1] This species was named by R. Tucker Abbott in 1958, in his publication on the marine mollusks of the island of Grand Cayman.

[2] But by 1974, in his book "American Seashells", Abbott had decided that the shell was simply a juvenile of what is now called Montfortia emarginata.

However, the species was re-instated by James McLean in a 2011 monograph on the subfamily Emarginulinae.

This Fissurellidae-related article is a stub.