Abstract: | A new genus and species of the family Parabathynellidae, Siambathynella laorsriae gen. nov. et sp. nov. is described from Thailand. The new genus displays an exclusive character: a distinctive male thoracopod VIII with a row of denticles on the basipod. The new species also displays a unique combination of morphological characters, including a seven-segmented antennule, seven-segmented antenna, sexual dimorphism on the antennule, exopod of thoracopod I one-segmented, exopod of thoracopod II–VII two-segmented, male thoracopod VIII lacking basipodal seta, female thoracopod VIII with two setae, lacking pleopods, sympod of the uropod with inhomonomous row of spines, and endopod of uropod with a spinous distal process and a large distal spine ornamented with rows of setules. This is the first record of Bathynellacea (family Parabathynellidae) in Thailand, extending the distributional range of this taxon in Asia. |