Two new species of Pycnophyidae are described from Japanese waters. Fujuriphyes longispinosus sp. nov. is easily distinguished from the congeners by the presence of extremely long lateral terminal spines, combined with the presence of middorsal elevations at least on segments 1–6, paradorsal setae on segments 2, 4, 6, and 8, pairs of laterodorsal setae on segments 2–9, lateroventral setae on segments 2, 4, 6, 8, and 10, pair of ventrolateral setae on segments 1, 3–8, and 10, with two pairs on segment 5, and ventromedial setae on segments 2 and 9 only. Leiocanthus parapardosi sp. nov is recognized by the absence of middorsal structure specializations throughout the trunk segments, and the presence of paradorsal setae on segments 2–9, laterodorsal setae on segments 2–9, lateroventral setae on segments 2, 4, 6–8, 10, ventrolateral setae on segments 5, 8, and 10, and ventromedial setae on segments 2–7. and 9, as well as by the presence of longitudinal cuticular thickenings on both sides of segment 10. Moreover, both species are characterized by the lack of ventromedial tubes on segment 2 in males.
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