Chaetocnema (Udorpes), Motschulsky, 1845, Motschulsky, 1845

Ruan, Yongying, Yang, Xingke, Konstantinov, Alexander S., Prathapan, Kaniyarikkal D. & Zhang, Mengna, 2019, Revision of the Oriental Chaetocnema species (Coleoptera, Chrysomelidae, Galerucinae, Alticini), Zootaxa 4699 (1), pp. 1-206 : 127-129

Key to species of subgenus Udorpes

1. Body length exceeds 3.00 mm........................................................................... 2

- Body length less than 3.00 mm.......................................................................... 3

2. Antennae long, reaching middle of elytra, dorsum metallic green................. Chaetocnema merguiensis Bryant, 1941

- Antennae normal, not extending to middle of elytra, dorsum cupreous................ Chaetocnema cupreata Chen, 1934

3. Body length less than 1.70 mm .......................................................................... 4

- Body length exceeds 1.70 mm ........................................................................... 5

4. Pronotal base obviously expanded and convex at middle; body strongly convex at sides, body strongly narrowed and pointed towards posterior end...................................................... Chaetocnema paraumesaoi sp. nov.

- Pronotal base evenly and very slightly convex at middle; body slightly convex at sides, posterior end of body rounded.............................................................................. Chaetocnema umesaoi Chûjô, 1961

5. Vertex covered with extremely weak and shallow punctures, hardly visible; vertex impunctate in middle....................................................................................... Chaetocnema reteimpunctata sp. nov.

- Vertex covered with large punctures, without impunctate area in middle (in rare cases there is an extremely narrow longitudinal impunctate area in middle).............................................................................. 6

6. Antennae very short, not reaching base of elytra; wingless, humeral calli absent............. Chaetocnema glabra sp. nov.

- Without such combination of characters................................................................... 7

7. Body strongly elongate and narrow; body length to width proportion exceeds 2.00; elytron length (along suture) to width (maximum) proportion exceeds 3.00........................................................................... 8

- Body normal, not strongly elongate....................................................................... 9

8. Pronotal punctures extremely bold; the distance between adjacent punctures equal to or smaller than diameter of punctures; hind wings highly reduced.................................................. Chaetocnema alticola Maulik, 1926

- Pronotal punctures normal, distance between punctures 1-2 times more than the diameter of punctures................................................................................. Chaetocnema shanxiensis Chen & Wang, 1980

9. Elytral punctures regular, arranged in single rows (excluding peri-scutellar punctures).............................. 13

- Elytral punctures not placed in single regular rows, confused or geminate........................................ 10

10. Elytral punctures partially geminate; peri-scutellar punctures tripled. Pronotal punctures minute, extremely closely placed............................................................................ Chaetocnema psylloides Pic, 1909

- Punctures on elytra confused or extremely closely placed with extra rows........................................ 11

11. Elytra extremely closely punctate with 15-17 rows of punctures............................................... 12

- Elytra not extremely closely punctate; however, confusedly punctate, punctures somewhat arranged in paired rows in the middle of elytron........................................................ Chaetocnema pusaensis Maulik, 1926

12. Aedeagus without apical denticle, apical third of aedeagus straight; dorsum with punctures extremely strong and much larger than those in C. malayana , interspace of pronotal punctures 0.5-1 times larger than their diameter; interspace of elytral punctures 1-1.5 times larger than their diameter................................. Chaetocnema concinnipennis Baly, 1877

- Aedeagus with apical denticle, apical third of aedeagus bent ventrally; dorsum with punctures finer than C. concinnipennis , interspace of pronotal punctures 1-2 times larger than their diameter; interspace of elytral punctures 1.5-2.5 times larger than their diameter............................................................. Chaetocnema malayana Baly, 1877

13. Basal third of pronotum strongly narrowed and constricted, narrower than middle; inter-antennal space narrow, width of interantennal space to width of antennal socket less than 1.5; pronotum only slightly wider than long, width to length ratio less than 1.5................................................................................................ 14

- Base of pronotum not strongly narrowed and constricted, not narrower than middle................................ 15

14. Body robust, cylindrical; lateral sides of elytra parallel........................... Chaetocnema cylindrica ( Baly, 1874)

- Body normal, ovate; lateral sides of elytra convex...................... Chaetocnema modesta Gressitt & Kimoto, 1963

15. Pronotum with a longitudinal impunctate area in middle..................................................... 16

- Pronotum without an impunctate area in middle............................................................ 20

16. Hind wings absent, antero-lateral angle of pronotum invisible from dorsal view....... Chaetocnema rahlensis Shukla, 1960

- Hind wings entire, antero-lateral angle of pronotum visible from dorsal view..................................... 17

17. Body length exceeds 2.40 mm .......................................................................... 18

- Body length less than 2.40 mm ......................................................................... 19

18. Elytra strongly costate at sides, peri-scutellar punctures form three or four rows; inter-antennal space about as wide as antennal socket.................................................................. Chaetocnema westwoodi Baly, 1877

- Elytra not costate or only slightly costate; peri-scutellar punctures arranged in two short rows, occasionally more than two lines; inter-antennal space obviously wider than antennal socket.......................... Chaetocnema ingenua ( Baly, 1876)

19. Peri-scutellar punctures form four rows; frons and orbit extremely strongly and closely punctate, with interspace of punctures narrower than diameter of punctures......................................... Chaetocnema midimpunctata sp. nov.

- Peri-scutellar punctures geminate; frons and orbit normally punctate, with interspace wider than diameter of punctures.......................................................................... Chaetocnema modiglianii Jacoby, 1896

20. Head narrow, orbit narrow; ratio of width between inner-margin of eyes to width of diameter of eye less than 2.00; supra-orbital sulcus, supra-antennal and supra-frontal sulci ‘W’ shaped.................................................... 21

- Head and orbit normal or wide; ratio of width between inner-margin of eyes to width of diameter of eye more than 2.00... 22

21. Pronotum quadrate, lateral sides straight and parallel to each other................... Chaetocnema angustifrons sp. nov.

- Pronotum not quadrate, lateral sides convex and slightly converging forward.............. Chaetocnema belli Jacoby 1904

22. Elytra strongly costate; vertex strongly punctate, with punctures as large as those on frons.......................... 23

- Elytra not strongly costate or only costate at sides........................................................... 24

23. Body length 1.90–2.00 mm; peri-scutellar punctures single or slightly geminate........ Chaetocnema singala Maulik, 1926

- Body length exceeds 2.20 mm, body robust; peri-scutellar punctures usually form three rows, occasionally geminate............................................................................. Chaetocnema bretinghami Baly, 1877

24. Body somewhat broad, pronotum broad, base of pronotum as wide as that of elytra................................ 25

- Body normal, pronotum not conspicuously broad, base of pronotum narrower than elytral base....................... 28

25. A shallow transverse depression present near the base of pronotum; hind wings absent............................................................................................... Chaetocnema sulcicollis Chen & Wang, 1980

- Base of pronotum without a transverse depression.......................................................... 26

26. Dorsum shiny metallic green; supra-antennal and supra-orbital sulci obsolete, covered by punctures; the space between eye and antennal socket wide and densely covered with coarse punctures........................ Chaetocnema greenica sp. nov.

- Dorsum not metallic green, supra-antennal and supra-orbital sulci present; space between eye and antennal socket narrow... .................................................................................................. 27

27. Peri-scutellar punctures single or partially geminate; apical denticle of aedeagus wide and truncate with concave apex............................................................................. Chaetocnema paragreenica sp. nov.

- Peri-scutellar punctures geminate; apical denticle of aedeagus narrow and flat at top..... Chaetocnema latapronota sp. nov.

28. Antennae robust and shortened, not extending beyond humeral calli over pronotum................................ 29

- Antennae slender and long, extending slightly beyond humeral calli over pronotum................................ 30

29. Anterolateral calli of pronotum well developed, produced antero-laterally, truncate and oblique, prominent from upper view.................................................................. Chaetocnema zangana Chen & Wang, 1981

- Anterolateral calli of pronotum not strongly produced, rounded, not prominent from upper view........................................................................................... Chaetocnema kumaonensis Scherer, 1969

30. Peri-scutellar punctures form three rows................................... Chaetocnema concinnicollis ( Baly 1874)

- Peri-scutellar punctures geminate........................................................................ 31

31. Head evenly and strongly punctate; frons, orbit and vertex evenly punctate with equally strong punctures......................................................................... Chaetocnema eastafghanica Konstantinov et al., 2011

- Head with frons more strongly punctate than vertex; punctures on vertex shallow and distant........................ 32

32. Pronotum widened anteriorly, with base narrower than apex.......................... Chaetocnema bella ( Baly, 1876)

- Pronotum not widened anteriorly, with base as wide as or wider than apex....................................... 33

33. Peri-scutellar punctures geminate or occasionally form three rows, peri-scutellar rows of punctures reach the middle of elytra; hind wings reduced.......................................................... Chaetocnema cognata Baly, 1877

- Peri-scutellar punctures form single row or geminate, with fewer punctures than in C. cognata , peri-scutellar rows of punctures short, not reaching the middle of elytra......................................... Chaetocnema afghana Gruev, 1988