Mopalia lignosa, the woody chiton, is a medium to large-sized species of polyplacophoran mollusc in the family Mopaliidae.

[1][2][3][4] This species was first described in 1846 by the conchologist Augustus Addison Gould[1][2] and can be found on the west coast of the United States, Mexico and Canada.

The structure of the valves consists of a strong V-shape ridge and fine radial lines.

This chiton can be found in the intertidal zone and mostly lives on the bottoms or sides of large boulders on open coasts.

[3] The eggs hatch into planktonic trocophore larvae, which means they form part of the meroplankton.