In this paper, we propose the reassignment of three western Atlantic species of the order Dendrochirotida to the family Sclerodactylidae (Euthyonidiella occidentalis comb. nov., Euthyonidiella arenicola comb. nov., and Thandarum manoelina comb. nov.) with a discussion on the classification of the dendrochirotids based on the morphology of the calcareous ring. We also propose the synonymization of Euthyonidiella dentata with Euthyonidiella occidentalis comb. nov., designate a neotype for this species and for Thandarum manoelina, and describe a new species of the genus Cucumaria from Brazil.