Japan: Ohara, 1994
Key to the Japanese species of the genus Platylomalus Cooman
1(4) Apical end of marginal elytral stria extending to suture of elytra, and curved at medio-posterior angle of elytra, then extending anteriorly.
2(3) Disk of mesosternum with a transverse stria, which is trapezoid (Fig. 86B). Pygidium of female deeply engraved with furrows (fig. 97C). ........................................ P. fujisanus (Lewis, 1892)
3(2) Disk of mesosternum without transverse stria (Fig. 107B). Pygidium of female densely punctate at apex, not engraved with furrows. ............................................ P. viaticus (Lewis, 1892)
4(1) Apical end of marginal elytral stria not attaining to suture of elytra.
5(6) Elytra coarsely punctate, the area along oblique humeral depression with large punctures (Fig. 110A). Disk of mesosternum without a transverse stria. ..................................... P. kusuii M. Ôhara, sp. nov.
6(5) Elytra rather evenly punctate, without large punctures. Disk of mesosternum with a transverse stria. (In P. mendicus, the transverse stria sometimes absent.)
7(8) Transverse stria of mesosternum trapezoid (Fig. 105B). Mesotibia clearly with 3 spines. Metatibia with 1 spine. Pygidium of female engraved with a large and ocelloid sculpture. ........................... P. persimilis (Lewis, 1888)
8(7) Disk of mesosternum with a transverse stria, which is smoothly curved and sometimes interrupted. Mesotibia with 4 spines. Metatibia with 2 spines.
9(10) Body length 3.0 - 3.5 mm. Marginal stria of pronotum nearly complete anteriorly. Pygidium of female engraved with irregular furrows except on its margin. .................................... P. niponensis (Lewis, 1899)
10(9) Body length 1.8 - 2.3 mm. Marginal stria of pronotum broadly interrupted at anterior middle. Pygidium of female engraved with two small circular sculptures (Fig. 99D). ............................ P. mendicus (Lewis, 1892)