We describe four new species of Solenogastres (Mollusca, Aplacophora) from the South China Sea (West Pacific). In addition to the morphological descriptions, we sequenced two mitochondrial genes. Phylogenetic analysis revealed the non-monophyly of the family Proneomeniidae. Ancestral character state reconstruction indicates that some characters commonly used in solenogaster taxonomy need to be revaluated. Thus, this work fills in knowledge gaps regarding the diversity and distribution of solenogasters and raises important questions about their taxonomy and systematics.

We revise Norfolk Island’s endemic land snails from the families Microcystidae and Helicarionidae using comparative morphology and phylogenetic analyses of mitochondrial DNA. We remove eight species from synonymy, place 10 species in synonymy, describe three new species, and demonstrate that 27 species belong to Microcystidae and only one species to Helicarionidae. Seven species or subspecies are likely to be extinct. We hypothesise that extreme differences in shell form in closely related taxa may result from adaptation to different ecological niches.

We discovered a new species of ribbon worm, Acteonemertes orientalis sp. nov. that belongs to the family Plectonemertidae. The species was found inhabiting the supratidal zone under rocks, wave-dissipating concrete blocks and fallen leaves, where nemerteans are rarely observed. Our molecular phylogeny suggested that this species forms a clade with Leptonemertes cf. chalicophora from Florida, USA. Although the feeding habits of the genus remain unknown, we observed that A. orientalis feeds on isopods that occur sympatrically in the natural habitat.