A metal separator defines a fluid passage. The fluid passage defines a reactant gas passage formed at a first, MEA-opposing surface of the metal separator, a coolant passage formed at a second, opposite surface of the metal separator, a reactant gas manifold fluidly connected to the reactant gas passage and a coolant manifold fluidly connected to the coolant passage. The metal separator includes a rib formed thereon so as to surround a portion of the metal separator where the fluid passage is formed. The rib is adapted to contact a metal separator of an adjacent fuel cell to construct a seal for a fluid passage surrounded by the rib. A plurality of seal lines where each seal line includes each rib may be provided. By virtue of the presence of the rib, a gasket provided in a fuel cell of comparison does not need to be provided.