Artabe et al. (2005) described a new fossil cycad genus, Chamberlainia, from the Allen Formation (Late Cretaceous) of Baja de Santa Rosa, Río Negro Province, Argentina. Unfortunately, this name is preoccupied by a moss genus in the Brachytheciaceae, described by Grout (1928). Thus, Chamberlainia Artabe, Zamuner & D. W. Stev. is a later homonym (Art. 53.1, ICBN Vienna) and a new name is required.