The swimming crabs (family Portunidae) are distributed worldwide and commonly inhabit estuaries, mangroves, reefs, shallow and the deep sea. Previously, 75 species and 19 genera in this family were known to Taiwan. Our study examined specimens in Taiwanese waters, including the islands, collected between 2016 and 2020 or deposited in museums. Through the cytochrome oxidase subunit I DNA barcode marker and morphological examination, 71 species were identified. The minimum interspecific distances were greater than 4.09%, except in two unresolved groups: Charybdis miles (De Haan, 1835) and Ch. sagamiensis Parisi, 1916, as well as Thranita pelsarti (Montgomery, 1931) and Thr. prymna (Herbst, 1803). In addition, 14 species belonging to nine genera were confirmed as new records to Taiwan, viz. Carupa ohashii Takeda, 1993, Lupocyclus inaequalis (Walker, 1887), Luu. tugelae Barnard, 1950, Lupocycloporus minutus (Shen, 1937), Monomia gladiator (Fabricius, 1798), M. lucida Koch & Ďuriš, 2018, Podophthalmus minabensis Sakai, 1961, Thalamita gatavakensis Nobili, 1906, Tha. spinifera Borradaile, 1902, Thalamitoides quadridens A. Milne-Edwards, 1869, Tho. tridens A. Milne-Edwards, 1869, Thr. cerasma (Wee & Ng, 1995), Thr. coeruleipes (Hombron & Jacquinot, 1846) and Xiphonectes tuberculosus (A. Milne-Edwards, 1861). This study thus raises the total number of Portunidae species in Taiwan to 89.
Keywords: Barcodes; Mitochondrial cytochrome oxidase subunit I (COI); Morphology; Newly recorded species.