Cystopeltidae redefined: integrative taxonomy of the Australian endemic slug Cystopelta with the description of 11 new species and subspecies (Punctoidea: Stylommatophora)

Cystopeltidae currently comprise the Australian endemic slug genus Cystopelta, a group with just five species, and several snail species from Australia and South America recently placed in this group on the strength of molecular phylogenetics. We herein comprehensively revise the genus Cystopelta using comparative morpho-anatomy and phylogenetic analyses of mitochondrial (COI, 16S) and nuclear (ELAVI8) DNA and investigate the status of the snails recently assigned to Cystopeltidae with the addition of the nuclear marker ITS2. We demonstrate that the snails Scelidoropa, Diemenoropa, Lilloiconcha, and Zilchogyra are not cystopeltids but belong to Charopidae where they are the sister taxon to all other charopids. The Australian snail genera Ngairea, Hedleyoconcha, Setomedea, Lenwebbia, Mussonula, Excellaoma, Annoselix, Pasmaditta, and Planilaoma are formally placed in Cystopeltidae on the strength of molecular phylogenetics and their lack of a complete secondary ureter, which they share with Cystopelta. We redescribe the species Cystopelta petterdi, Cystopelta astra, Cystopelta bicolor, Cystopelta purpurea, and Cystopelta septentrionalis, and newly describe eight species and three subspecies: Cystopelta astra flava subsp. nov., Cystopelta barringtonia sp. nov., Cystopelta bassiana sp. nov., Cystopelta bassiana bassiana subsp. nov., Cystopelta bassiana cinerea subsp. nov., Cystopelta jimhymani sp. nov., Cystopelta nunniong sp. nov., Cystopelta pauperocochlea sp. nov., Cystopelta rafflesorum sp. nov., Cystopelta riparia sp. nov., and Cystopelta tallaganda sp. nov. [Version of Record, first published online 27 May 2026, with fixed content and layout in compliance with Art. 8.1.3.2 ICZN. https://zoobank.org/urn:lsid:zoobank.org:pub:4B8FE50E-CFBC-48C5-9147-4BCE1A48FE0A]