Trapania bonellenae, a new species from Bonaire, Netherlands Antilles belonging to the nudibranch family Goniodorididae, is characterized by having a unique translucent grey color with a pattern of black pigment, a complex network of opaque white lines covering almost the entire notum and very elongate extra-branchial and extra-rhinophoral appendages. The radular teeth are characterized by a very long and narrow subterminal cusp. A phylogenetic analysis of all species of Trapania for which there is enough morphological information available, reveals that the new species is most closely related to a group of mostly Indo-Pacific species. The support and resolution for this clade are weak and more research is necessary.