Seven species of freshwater crabs from three families are recorded from and around the Danum Valley Conservation Area in Sabah, Malaysian Borneo: Thelphusula capillodigitussp. n., Thelphusula dicerophilus Ng & Stuebing, 1990, Arachnothelphusa terrapes Ng, 1991, Terrathelphusa secula Ng & Tan, 2015, Parathelphusa valida Ng & Goh, 1987 (new record) (Gecarcinucidae); Isolapotamon ingeri Ng & Tan, 1998 (Potamidae); and Geosesarma danumense Ng, 2002 (Sesarmidae). The new species of Thelphusula Bott, 1979, can be distinguished from all congeners by a unique combination of morphological features, most notably the presence of dense patches of short setae on the fingers of the adult male chelipeds, as well as the structure of the male first gonopod. Arachnothelphusa terrapes is confirmed to be a phytotelm species. A key to all species in the conservation area is provided.
The genus Kelawakaju Maddison & Ruiz, gen. nov., is described for a lineage of bark-dwelling Asian marpissine jumping spiders that represent a dispersal to Eurasia separate from that of the Marpissa-Mendoza lineage, according to the phylogeny recovered from analysis of four gene regions. All species of Kelawakaju are new to science except Kelawakajufrenata (Simon, 1901), comb. nov., which is transferred from Ocrisiona Simon, 1901. Kelawakajufrenata is known from Hong Kong, Guangdong, Guangxi, and likely Taiwan. The five new species are Kelawakajumulu Maddison & Ruiz, sp. nov. (type species of Kelawakaju, from Sarawak, Malaysia, ♂♀), K.intexta Maddison & Ruiz, sp. nov. (from Sarawak, ♂), K.leucomelas Maddison & Ng, sp. nov. (Singapore and Johor Bahru, ♂♀), K.sahyadri Vishnudas, Maddison, & Sudhikumar, sp. nov. (India, ♂♀), and K.singapura Maddison & Ng, sp. nov. (Singapore, ♂♀).