A new decapod brachyuran, Maurocarpilius binodosus n. gen., n. sp. (Carpiliidae Ortmann, 1893), from the Ait Ouarhitane Formation (early Eocene, Ypresian) of Tamalout (Ouarzazate, Morocco) is described herein. This is the first record of a decapod from the Eocene of Morocco formally reported, and represents an addition to the large record of carpiliids from the Paleogene of the western margin of the Tethys. The new taxon is characterized as follows: a strongly vaulted and smooth carapace, a front strongly downturned, anterolateral margins broadly convex with two small nodes, and concave posterolateral margins. Maurocarpilius binodosus n. gen., n. sp. presents clear morphological similarities with coeval taxa from the northern Iberian Peninsula and northern Italy, and the origins of those taxa and their possible phylogenetic relationships are discussed. Moreover, the paleobiogeography of the populations of carpiliids during the early Eocene in the western end of the Tethys is analyzed, and a possible connection between the Tethys Sea and the Bay of Biscay, that could have favored the faunal exchange between the North Atlantic and the Tethyan domains, is proposed.