A new genus and species of Hydrobiidae is described from north central Peloponnese peninsula, Greece: Tridentalia lykaia. Additionally a note on Achaiohydrobia Falniowski, 2021 is given: Achaiohydrobia moreana Hofman & Grego, 2021 is a junior synonym of Bythinella corrosa Glöer & Hirschfelder, 2020.
While a few species of the genus Diaphera Albers, 1850 are reported in mainland Southeast Asia (Thailand, southern China, northern Vietnam, Myanmar), most species occur in the Philippines. In this paper we provide photographs of all Philippine species, and mostly based on the material of the Florida Museum of Natural History, we describe elevennew species and a subspecies as follows: Diaphera costatuba Páll-Gergely & Auffenberg, spec. nov., D. cyclostoma Páll- Gergely, spec. nov., D. gracilimajor Páll-Gergely, spec. nov., D. graciliminor Páll-Gergely, spec. nov., D. orca Páll-Gergely & Auffenberg, spec. nov., D. princessa Páll-Gergely, spec. nov., D. thompsoni Páll-Gergely & Auffenberg, spec. nov., D. tubella Páll-Gergely & Auffenberg, spec. nov., D. vespertilio Páll-Gergely, spec. nov., D. neolophia Páll-Gergely, spec. nov., D. bacillum Páll-Gergely & Auffenberg, spec. nov., D. hidalgoi skrik Páll-Gergely, subspec. nov. With this, the number of Diaphera species increases to 70, 52 of them inhabiting the Philippines. The juvenile apertural barriers are described for the first time in several species, which can be used to hypothesize about the evolutionary relationships of species and species groups within Diaphera. Biogeography of the genus is briefly discussed. The reproductive anatomy and radula morphology of four species are described. An epiphallus was found for the first time in the family Diapheridae.