A new ostracod found in the Mississippian of the Cantabrian Mountains shows ornamental features similar to Criboconcha Cooper, hitherto known from Mississippian and Pennsylvanian strata of different parts of the world (especially from the U.S.A.). However, some features of this ostracod are very different from the typical characteristcs of the Healdiidae and support bairdiocyproidean affinities. The new genus Pseudocriboconcha (type species Pseudocriboconcha prinsi sp. nov.) is proposed. This species is distinguished by distinct pits on the lateral surface; a posterior ridge ending in dorsal and ventral spines; a rounded rim parallel to the borders of each valve; and a spine on this rim, above the anterior end and directed dorsally or anterodorsally.