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Partulidae, a Pacific Island tree snail family of extreme conservation concern, has been the subject of multiple taxonomic revisions in recent years. In addition to numerous changes at the species level, one new genus (Sphendone Slapcinsky & Kraus, 2016) has been proposed and two preexisting taxa (Rennellia Clench, 1941 and Palaopartula Pilsbry, 1909) have been elevated to genus level, with all three genera based primarily on qualitative appraisals of traditional morphological (shell and soft parts) characters. The limited phylogenetic analyses inclusive of these three genera provide poor-to-ambivalent support for their respective phylogenetic distinctiveness, in part due to the paucity of available genetic markers, but also due to rooting issues caused by a lack of Partulidae sister lineages. We aimed to address both deficiencies by performing double digested Restriction Associated DNA (ddRADseq) phylogenomic analyses that incorporated putative Partulidae sister lineages in addition to type species of the three new, and three pre-existing (Partula Férussac, 1821; Samoana Pilsbry, 1909; and Eua Pilsbry & C. M. Cooke, 1934), Partulidae genera, along with representative congeners spanning their respective ranges. Among the six pupilloidean outgroup families investigated, our results tentatively placed Valloniidae and Gastrocoptidae as sisters to Partulidae and recovered three robust ingroup clades: (Eua (Samoana, Partula)). Rennellia was firmly nested within the Partula clade (sister to Marianas species) and a paraphyletic Palaopartula/Sphendone n. gen. within the Samoana clade [sister to the Marianas species Samoana fragilis (Férussac, 1821)]. Because reciprocal monophyly is widely accepted as a minimum prerequisite of generic status, these data compelled us to return to the traditional three-genus model for Partulidae. That redesignation was strongly corroborated by molecular clock divergence time estimates and by the presence of phylogenetic gaps, but less so by crown group definitions or the uniqueness of adaptive zones. It significantly expanded our conception of the genus Samoana in terms of its evolutionary history, species composition and ecological diversity. Our phylogenomic results also provided new insights into the enigmatic biogeography of this family, locating the origins of all three genera within neighboring archipelagos and identifying for the first time a sister species to the fabled Society Islands Partula radiation.