Two new terrestrial crab species of the family Potamidae, Tiwaripotamon xuanson and T. hamyen, are described from northern Vietnam. Tiwaripotamon xuanson was collected from Xuan Son National Park, Thanh Son district, Phu Tho province, and T. hamyen was found in Binh Xa commune, Ham Yen district, Tuyen Quang province. They can be distinguished from other congeners by distinct carapace characteristics and gonopod 1 structures.

Two new species of the Indochinese tree snail Anceyoconcha S. Tumpeesuwan & C. Tumpeesuwan, in Nahok et al., 2020, are described from natural forests and forestry plantations on sandstone and basalt hills in northeastern Thailand. These snails can be found on trees from the foothills to higher elevations, around 1–2 m above ground level. The new species Anceyoconcha carinata and Anceyoconcha elongata possess the key characters of the genus, namely, a shell that is sinistral, ovate conic to elongate conic with six to nine slightly convex whorls, semi-transparent, and lustrous. The dart sac and mucous glands are absent, and the flagellum long cylindrical and tapering. Both new species differ from all previously described species by unique characters of shell; length of penis, vagina and free oviduct; and flagellum shape. The phylogeny based on the mitochondrial and nuclear DNA and genetic distances suggest that all Anceyoconcha species form a well-supported monophyly, and that both new species are differentiated from the rest of the congeners.

Two new and relatively large species of semi-terrestrial sesarmid crabs of the genus Geosesarma De Man, 1892, are described from Palawan Island, Philippines. They are distinguishable from congeners by the characteristic structure of their carapace, chelipeds, ambulatory legs and male first gonopods. Aspects of their ecology are briefly discussed.

This paper describes two new species of heteraxinid monogenean worms belonging to the rare and little-known genus Karavolicotyla, which were collected from two species of marine sciaenid fishes in Vietnam. Karavolicotyla tuyeti,new species, and K. ruber,new species, were found on the gills of Nibea albiflora and Otolithes ruber, respectively. Descriptions of the new species were based on morphology and morphometry. Both new species are characterised by having clamps on both sides of the haptor, arranged in two unequal rows; the cirrus and the genital atrium being armed; the dorsomedial vaginal opening located immediately distal to the level of the genital aperture, and the accessory vaginal opening being absent. Moreover, K. tuyeti, new species, can be separated from its congeners by the following characters: the number of clamps is 29 (29‒30) in the short row and 43 (40‒46) in the long row; the number of spines of the genital atrium is 52 (50‒56) and its length is 32 (28‒36) μm; the spherical cirrus with a single stout hook-like spine on top; and the number, size, and disposition of testes.Karavolicotyla ruber, new species,can be easily distinguished by the greater number of clamps (36, 50 in the short row and 69, 63 in the long row); the number of atrial spines (33, 34); the pine nut-shaped cirrus armed with a circlet of 14 short, strongly curved spines; and the number, size, and disposition of testes. An amendment to the morphological limits of the genus is proposed and its diagnostic characters are discussed

During a recent survey of the insect fauna of the mangroves of the San Vicente Mangrove Forest Association (SAVIMA) Bohol, Philippines, many Diptera specimens were collected. They were pre-sorted into putative species (3% threshold) using COI sequences obtained via next-generation-sequencing (“NGS barcodes”: 313bp). The sequences were then compared to a database with sequences for more than 15,000 Southeast Asian dolichopodid specimens belonging to >250 species. Sequences for two putative species were found to be new. Morphological study revealed that these species are new to science. Based on the presence of peculiar ventral bristles on the fore tibia and typical male terminalia, both belong to Thinophilus and are here newly described as Thinophilus lungosetole Ramos & Grootaert sp. nov. and Thinophilus ronazeli Ramos & Grootaert sp. nov. We provide extended diagnoses that are illustrated with stacked habitus photos, figures of the male terminalia and NGS barcodes. A checklist of all Dolichopodidae recorded in the Philippines is provided.

During a recent survey of the insect fauna of the mangroves of the San Vicente Mangrove Forest Association (SAVIMA) Bohol, Philippines, many Diptera specimens were collected. They were pre-sorted into putative species (3% threshold) using COI sequences obtained via next-generation-sequencing (“NGS barcodes”: 313bp). The sequences were then compared to a database with sequences for more than 15,000 Southeast Asian dolichopodid specimens belonging to >250 species. Sequences for two putative species were found to be new. Morphological study revealed that these species are new to science. Based on the presence of peculiar ventral bristles on the fore tibia and typical male terminalia, both belong to Thinophilus and are here newly described as Thinophilus lungosetole Ramos & Grootaert sp. nov. and Thinophilus ronazeli Ramos & Grootaert sp. nov. We provide extended diagnoses that are illustrated with stacked habitus photos, figures of the male terminalia and NGS barcodes. A checklist of all Dolichopodidae recorded in the Philippines is provided.