The genera Bresedium Serène and Soh, 1970 and Sesarmops Serène and Soh, 1970 are two closely related taxa inhabiting terrestrial or freshwater environments from the Indo-West Pacific. Based on morphological and molecular evidence, two new species from Taiwan, the Philippines and Indonesia are described in this study, viz. B. eurypleon n. sp. and S. mora n. sp. The new species can be distinguished from congeners by a suite of carapace, chelipedal, gonopodal and vulvar characters. Bresedium philippinense (Rathbun, 1914) is here shown to be a junior synonym of B. brevipes (De Man, 1889). A poorly known Philippine species, Sesarmops mindanaoensis (Rathbun, 1914), is redescribed from the type and fresh material, and is recorded for the first time from Taiwan.
Taxonomy, New species, Bresedium eurypleon, B. philippinense, Sesarmops mora, S. mindanaoensis, Morphology, Mitochondrial 16S rDNA, Cytochrome oxidase subunit I.
