Abstract

A new species of the canuellid genus Brianola Monard, 1926 (Copepoda: Harpacticoida) was collected during a meiofauna survey in July 2021 at the intertidal muddy sand of Phuket Island, Thailand. Currently, there are only eight known species of Brianola: B. stebleri, B. exigua, B. curvirostris, B. elegans, B. sydneyensis, B. vangoethemi, B. hamondi, and B. haliensis. Thus, the Brianola rawaiensis sp. nov. from Thailand is the ninth species of the genus. The new species, Brianola rawaiensis is most closely related to B. haliensis by sharing a four-segmented antennule in females and five-segmented antennule in males, eight-segmented antennary exopod and three-segmented antennary endopod, and P1 exp-3 with 5 spines/setae. However, B. rawaiensis sp. nov. is different from B. haliensis by having: 1) P1 exp-1 with 1 outer pinnate spine, 2) P1 exp-2 with inner plumose seta, 3) P2 exp-3 with 3 setae/spines, 4) P2 enp-1 with one inner plumose seta, 5) P4 enp-1 with inner seta. Sexual dimorphism is expressed in the antennule and segmentation of the urosome. Ovigerous female bearing one egg sac with 20 eggs.