Pseudopolyides furcellarioides gen. et sp. nov. (Gigartinales, Rhodophyta) was described from the Atlantic coasts of the northern Iberian Peninsula based on morphological and molecular evidence. This plant was found growing in the lower intertidal to the upper subtidal of moderately exposed rocky coasts, the bases anchored to rocks and often covered by sand. Thalli were perennial, terete, dichotomously branched and erect from a mammillate crustose holdfast. Fronds were multiaxial with a compact filamentous medulla, a densely pseudoparenchymatous inner cortex and an anticlinal outer cortex. Gametophytes were dioecious and isomorphic to tetrasporophytes. Spermatangia were superficial on swollen branch tips. Gonimocarps were spindle-shaped and directed to the thallus interior, while tetrasporangia were zonate. The habit and internal structure resembled those of both Polyides rotundus (characterized by crustose holdfasts, dichotomous or trichotomous branching and similar longitudinal section) and Furcellaria lumbricalis (distinguished by internal gonimocarps and zonate tetrasporangia). All three species occasionally occurred sympatrically in the Iberian Peninsula and were easily misclassified. Molecular phylogenetic analyses placed Pseudopolyides furcellarioides within the previously monogeneric Cruoriaceae, making it the first non-crustose representative of this family.