Two new species of the genus Upogebia (Decapoda: Gebiidae: Upogebiidae) from the South China Sea are described. Upogebia jiaruii, new species, most closely resembles Upogebia baweana Tirmizi & Kazmi, 1979 but differs markedly in having two smooth, strong transverse carinae on the dorsal surface of the telson. Upogebia ruiyui, new species, most closely resembles Upogebia allspachi Sakai, 2006 but differs markedly in having two transverse denticulate carinae on the dorsal surface of the telson and without sharp upper spine on the propodus of pereopod

Two new species of the mangrove crab genus Leptarma Shahdadi, Fratini & Schubart, 2020, are described herein. Leptarma schubarti, new species, is described from Vanuatu and Palau, and is shown to have a close phylogenetic association to L. aurifrons (Li, Shih & Ng, 2019) from Taiwan. It differs significantly from L. aurifrons and other congeners in the structure of the first gonopod and vulva, which have a long, narrow apical corneous process, and a broadly oval operculum along the inner side with a distinct sternal cover, respectively. Leptarma bertrandi, new species, is described from the Loyalty Islands (New Caledonia), Vanuatu, and Taiwan. This species is shown to have both close morphological and genetic affinity to L. lenzii (De Man, 1895) from western Sumatra and the Cocos (Keeling) Islands, but can be distinguished from L. lenzii s. str. by several key morphological features including its live colour pattern. Compared to L. lenzii, L. bertrandi, new species, has proportionally longer ambulatory legs, fewer dactylar tubercles on the chelae, and the first gonopod has a shorter apical corneous process. Therefore, the number of recognised species of Leptarma now rises to 22, of which four occur in the oceanic islands of the Western Pacific. Present genetic analyses once again show that COX1 may not be the best marker for molecular taxonomy and species delimitation in this genus as it is not able to separate morphologically distinct species.

The mirine plant bug genus Adelphocorisella Miyamoto & Yasunaga, 1993 is reported from Central Thailand and the Oriental Region for the first time. Two new species, A. adelphocoroides and A. sarika, are described, with habitus images of live individuals. Generic characters are reviewed, and the phylogenetic relationship of Adelphocorisella to superficially similar genera is discussed

Two new psolid sea cucumber species are described from the 2010–2013 Comprehensive Marine Biodiversity Survey (CMBS) of the Johor Straits, Singapore: Psolidium helenae Ong & O’Loughlin, new species and Psolidium wongae Ong & O’Loughlin, newspecies. Psolidium helenae differs from other tropical Psolidiumspecies by having: a low profile; a band of tube feet around the periphery of the sole up to six wide; an absence of smaller outer marginal tube feet on the sole; a band of mid-ventral tube feet on the sole about five wide; distally spinous cupped cross ossicles present dorsally. Psolidium wongaediffers from other tropical Psolidium species by having: low profile; tube feet series around the periphery of the sole up to about 10 wide; an absence of smaller outer marginal tube feet on the sole; an absence of cupped cross ossicles dorsally and ventrally. Psolus fimbriatusSluiter is referred to Psolidium Ludwig, as are Psolus boholensis Semper and Psolus complanatus Semper. Variety Psolus boholensis var. pandanensis Semper is raised to species status and also assigned to Psolidium. A key to 15 tropical East Indian–West Pacific Psolidium species is provided for: Psolidium berentsae O’Loughlin & Maric; P. boholensis (Semper); P. complanatum (Semper); P. disjunctum Sluiter; P. fimbriatum (Sluiter); P. helenae newspecies; P. hutchingsae O’Loughlin & Maric; P. mccallumae O’Loughlin & Maric; P. minutum (H. L. Clark); P.pandanensis (Semper); P. parmatum (Sluiter); P. rugosum Koehler & Vaney; P. spinuliferum (H. L. Clark); P. translucidum Koehler & Vaney; P. wongae , new species.