Key to the species of Patrus Aubé occurring in China The following key is based on the species of which we have examined material from China. The following 13 species known from China were not included in the key because we were not able to examine any material of these species from China: Patrus metallicus (Régimbart, 1884), P. sculpturatus (Régimbart, 1884), P. chinensis (Régimbart, 1892), P. sublineatus (Régimbart, 1892), P. sulcipennis (Régimbart, 1892), P. fallax (Peschet, 1923), P. mimicus (Ochs, 1936), P. minusculus (Ochs, 1936), P. depressiusculus (Ochs, 1940), P. helferi (Ochs, 1940), P. distinguendus (Ochs, 1942), P. klapperichi (Ochs, 1942) and P. jaechi (Mazzoldi, 1998). 1. Labrum semi-circular, about half as long as wide, with anterior margin rounded ............................. ........................................................................................................................................................... 2 – Labrum short and wide, less than ⅓ as long as wide, with anterior margin truncate or slightly convex ............................................................................................................................................... 6 2. Epipleural angle of elytra prolonged into a spine (Fig. 11E) .................. P. annandalei (Ochs, 1925) – Epipleural angle of elytra not prolonged into a spine ....................................................................... 3 3. Labrum bright yellow, evidently differs from colour of clypeus (Fig. 15A) .................................... 4 – Labrum brown or black, concolorous with clypeus .......................................................................... 5 4. Size larger, long 5.5–6.0 mm ................................... P. marginepennis angustilimbus (Ochs, 1925) – Size smaller, long 4.0– 4.5 mm ..................................... P. marginepennis parvilimbus (Ochs, 1925) 5. Posterior margin of elytral glabrous region irregular, trilobate in apical ½ at each elytron (Fig. 13A– B) ............................................................................................... P. haemorrhous (Régimbart, 1891) – Posterior margin of elytral glabrous region evenly curved towards suture ........................................ .............................................................................................................. P. jilanzhui (Mazzoldi, 1998) 6. Pronotum and elytra without yellow or reddish lateral border ......................................................... 7 – Pronotum and elytra with yellow or reddish lateral border .............................................................. 8 7. Protarsus in male wider than protibia or at least as wide as protibia; apex of aedeagus needle-shaped; glabrous region in female produced at posterolateral area posteriorly ............................................... ................................................................................................... P. apicalis subapicalis (Ochs, 1930) – Protarsus in male narrower than protibia; apex of aedeagus regularly narrowed; glabrous region in female not produced at posterolateral area, but forming a clear angle ............................................... .............................................................................................................. P. landaisi (Régimbart, 1892) 8. Elytra very smooth, without obvious reticulation or punctation; epipleural angle of elytra prolonged into a spine ....................................................................................... P. productus (Régimbart, 1884) – Elytra with obvious punctation; epipleural angle of elytra not prolonged into a spine .................... 9 9. Lateral pubescence on pronotum strongly expanded inward anteriorly, at least reaching middle of the eye ............................................................................................................................................. 10 – Expansion of lateral pubescence on anterior pronotum never reaching middle of the eye, at most reaching outer third of the eye ........................................................................................................ 16 10. Surface of elytra with dense micro-punctation among the larger punctation (Fig.13F) ..................11 – Surface of elytra without obvious micro-punctations among the punctation ................................. 13 11. Dorsal habitus broader, epipleural angle not acute, narrowly rounded ............ P. melli (Ochs, 1925) – Dorsal habitus elongate, epipleural angle acute (Fig. 12G), but never prolonged into a spine ...... 12 12. Elytral glabrous region strongly sexually dimorphic: elytral glabrous region lanceolate in posterior ½ in male, elongate oval and weakly acuminate posteriorly in female (Fig. 12A–D) ....................... ................................................................................................................. P. coomani (Peschet, 1925) – Elytral glabrous region without evident sexual dimorphism, regularly cordiform ............................ ............................................................................................................ P. procerus (Régimbart, 1883) 13. Epipleural angle acute, but never prolonged into a spine .............................. P. hainanensis sp. nov. – Epipleural angle not acute, narrowly rounded ................................................................................ 14 14. Lateral borders on pronotum and elytra testaceous to dark testaceous ............................................... ...................................................................................................... P. emmerichi (Falkenström, 1936) – Lateral borders on pronotum and elytra yellow .............................................................................. 15 15. Elytral glabrous region oval, not acuminate posteriorly ..................................................................... .................................................................................... P. cribratellus cribratellus (Régimbart, 1891) – Elytral glabrous region cordiform, obviously acuminate posteriorly ................................................. ............................................................................................................ P. figuratus (Régimbart, 1892) 16. Lateral pubescence on pronotum not expanded or slightly expanded inwards anteriorly .............. 17 – Lateral pubescence on pronotum distinctly expanded inwards to about external third of the eye anteriorly ......................................................................................................................................... 20 17. Lateral pubescence on pronotum slightly expanded inwards; protarsus of male strongly expanded, almost as long as protibia ............................................................................................................... 18 – Lateral pubescence on pronotum never expanded inwards anteriorly, only reaching external edge of the eye; protarsus of male obviously shorter than tibiae ................................................................ 19 18. Aedeagus terminating with a reverse heart shape ....................................... P. chalceus (Ochs, 1936) – Aedeagus not terminating with a reverse heart shape, rounded apically ............................................ ..................................................................................................... P. schillhammeri (Mazzoldi, 1998) 19. Truncature of elytra straight ................................................................. P. severini (Régimbart, 1892) – Truncature of elytra slightly oblique ......................................................... P. assequens (Ochs, 1936) 20. Protarsus in male about as long as protibia .................................................................................... 21 – Protarsus in male clearly longer than protibia ................................................................................ 22 21. Elytral glabrous region regularly oval in both sexes, much wider posteriorly in female; median lobe broader apically ................................................................................................... P. wui (Ochs, 1932) – Elytral glabrous region regularly oval in male, with a postero-lateral expansions on each side in female (Fig. 5A–B); median lobe narrower apically ........................... P. shangchuanensis sp. nov. 22. Elytral glabrous region with minor sexual dimorphism, regularly oval in both sexes, wider posteriorly in female ........................................................................................................ P. jiangxiensis sp. nov. – Elytral glabrous region on elytra strongly sexually dimorphic: regularly oval in male, with a postero-lateral expansions on each side in female (Mazzoldi, 1998: figs 1, 4a) ... P. wangi (Mazzoldi, 1998)

Published as part of Liang, Zulong, Angus, Robert B. & Jia, Fenglong, 2021, Three new species of Patrus Aubé with additional records of Gyrinidae from China (Coleoptera, Gyrinidae), pp. 1-39 in European Journal of Taxonomy 767 on pages 32-34, DOI: 10.5852/ejt.2021.767.1481, http://zenodo.org/record/5715526