Two new species of the genus Zeuxo (Peracarida: Tanaidacea) from the west and south coast of Korea

Two new species of Zeuxo Templeton 1840 are described from the western and southern coast of Korea (North West Pacific). Zeuxo gracilis n. sp. and Z. spina n. sp. belong to the "Z. normani species complex". Zeuxo gracilis is distinguished from species within this complex by the following morphological combination in females: the spine row of the left mandible bears a bifid spiniform seta; pleonites 4 and 5 bear one and two lateral setae, respectively; the cheliped merus bears two ventral and two inner setae; and pereopods 2-6 bear a distal simple seta on merus. Zeuxo spina shows unique features characterized by a serrated ventral seta on each propodus of pereopods 2 and 3 and the cheliped merus bearing two ventral and one inner setae. Additional character states are proposed for defining new and/or sibling species within the Z. normani species complex. In order to confirm the presence/absence of morphological variations of Zeuxo, detailed morphological features between same- and different-sized females of Z. gracilis are compared and discussed.