Pagodapalaina, a new sinistral genus of Diplommatinidae from the Malay Peninsula and Sumatra, with description of a new species from Perak, Peninsular Malaysia (Gastropoda: Caenogastropoda: Cyclophoroidea)

A new diplommatinid genus, Pagodapalaina Z.-Y. Chen gen. nov., is erected for several sinistral species from the Malay Peninsula and Sumatra originally assigned to Diplommatina Benson, 1849. In addition, a new species of this new genus, Pagodapalaina hortulanica sp. nov., is described from Perak, Peninsular Malaysia. The genus Pagodapalaina gen. nov., is characterised by a sinistral and conical shell with a mostly keeled periphery; the radula consists of a strong central tooth with a large central cusp and smaller lateral cusps; the basal plate of the central tooth bears two small cusps; the lateral and marginal teeth have very short basal parts.

An annotated type catalogue of all known species is presented, with illustrations provided for most taxa. Additionally, Diplommatina laemsonensis Boonmachai, Bergey & Nantarat, 2023 and Diplommatina prakaiphetensis Boonmachai, Bergey & Nantarat, 2023 are recognised as synonyms of Pagodapalaina acme (Laidlaw, 1949) comb. nov., and Pagodapalaina sinistra (Tomlin, 1938) comb. nov., respectively.