Sellaea is a key genus for understanding the expansion of rudists in the middle Cretaceous. Its incursion into the Americas in the Albian is open to taxonomic debate, as several researchers have hypothesised that the American Sellaea belongs to a new genus. A taxonomic revision with analysis of new material from the Edwards Formation (Texas, USA) coupled with a cladistic analysis using three-taxon analysis allows us to redefine the genus Sellaea. The phylogeny reveals two distinct endemic groups, one belonging to the Mediterranean province, and one to the Caribbean province. However, the involved synapomorphies, related to the left valve posterior cavity, the shell margin, and the outline, are not sufficient to create a new genus. The character related to pallial canals is the only one to be homoplastic in the phylogeny of Sellaea. The presence of canals is therefore a variable character state within the genus. The genus is redefined accordingly, allowing the relocation of several species originally assigned to Caprotina, including species that lack pallial canals and species with unknown right valves. Sellaea minuta is the only species retained over the four Sellaea described from the Americas. The redefined genus Sellaea is Albian-Cenomanian in extent, with the incursion of a single species into North America in the Albian.