Key to species of the Platydracus brachycerus group

1 Body brownish to blackish; abdominal tergites VII and VIII without golden pubescent patches....................... 2

- Body bicolored with elytra and basal part of abdomen reddish; abdominal tergites VII and VIII each with golden pubescent patch......................................................................................... P. donnyi

2 Body with copper reflection; head with punctures very dense, but not contiguous, separated by less than a puncture diameter in transverse direction; tarsomere 5 of anterior leg 1.85–1.98 times as long as wide........................... P. smetanai

- Body without copper reflection; head with punctures relatively sparse, separated by about 1–2 puncture diameters in transverse direction; tarsomere 5 of anterior leg 3.15–3.58 times as long as wide............................................ 3

3 Head shorter, HW/HL: 1.21–1.26; antennomeres 5–11 with dense pubescence......................................4

- Head longer, HW/HL: 1.09–1.20; antennomeres 4–11 with dense pubescence...................................... 5

4 Pronotum with lateral sides distinctly curved inward in apical half; elytra with indistinct golden setae along posterior margin; aedeagal paramere slender with one seta at apex...................................................... P. gracilis

- Pronotum with lateral sides indistinctly curved inward in apical half; elytra with distinct golden setae along posterior margin; aedeagal paramere broad without setae at apex................................................... P. paragracilis

5 Head with temples more prominent and punctation coarser; pronotum shorter; aedeagal paramere long and bilobed with long setae at apex................................................................................ P. brachycerus

- Head with temples less prominent and punctation finer; pronotum longer; aedeagal paramere short and unbranched without setae at apex.................................................................................... P. juang