Helcionopsis subcarinata is an extinct species of paleozoic monoplacophoran in the family Tryblidiidae.

The anterior and posterior margins are subequal and sharply rounded in the middle.

One exhibits besides a series of muscular scars similar to those of Tryblidium.

They stated: "The lines are converging from them towards the apex are a peculiar feature, though probably of the nature of progressive tracts.

"[1] Trenton group, Clitambonites bed, Goodhue County, Minnesota.