Tritoniid sea slugs are specialised predators that feed on a variety of octocorals, including soft corals, gorgonians and sea pens. Trivettea papalotla is a recently described species found in Baja California and mainland Mexico that is unusual in its morphology and feeding behaviour. It is the first tritoniid nudibranch known to feed on zoanthid anthozoans, specifically on an undescribed species of the genus Epizoanthus. Trivettea papalotla also has retractable respiratory structures, prominent dorsal vessels and several other traits not found in any other species of the Tritoniidae. In its original description these unique features of T. papalotla were considered autapomorphies, and the species was tentatively placed within Tritonia based on a morphological phylogenetic analysis. Subsequently, the monotypic genus Trivettea was erected for T. papalotla based on unpublished molecular data. In the present study, the phylogenetic placement of Trivettea is investigated based on molecular data. These phylogenies show T. papalotla is not nested within Tritonia or Tritoniidae and instead appears to be a basal, distinct cladobranch. However, the analyses conducted resulted in poorly resolved basal relationships, suggesting additional markers are probably necessary to fully resolve the phylogeny for the Cladobranchia.