Algon (Schillhammer, 2006)

Li, Chong & Tang, Liang, 2023, New species and records of Algonina Schillhammer & Brunke, 2018, mainly from China, Zootaxa 5256 (5), pp. 457-482 : 471-472

Key to species of Algon from China (modified from Schillhammer 2006: 141; 2017:160)

1 Medial margin of eye distinctly bordered, in addition, with distinct punctate furrow along medial margin of eye.......... 2

- Medial margin of eye not bordered, without furrow along medial margin of eye................................... 19

2 Eyes very large, occupying almost entire side of head, at least four times as long as tempora......................... 3

- Eyes moderately large, less than three times as long as tempora................................................. 4

3 Pronotum with dorsal row of punctures, surface of elytra not wrinkled.. A. sinoculatus Schillhammer, 2006 China (Yunnan)

- Pronotum without dorsal row of punctures, surface of elytra wrinkled...... A. huadongensis sp. n. China (Fujian, Zhejiang)

4 Fore body without isodiametrical microsculpture............................................................ 5

- Fore body at least partially with dense isodiametrical microsculpture........................................... 15

5 Entirely black species.................................................................................. 6

- Forebody at least partially with metallic hue................................................................ 9

6 Narrow portion between infraorbital and postmandibular ridge coarsely punctate.................................. 7

- Narrow portion between infraorbital and postmandibular ridge virtually impunctate................................. 8

7 Segment 10 of antennae as long as wide or weakly oblong..................................................................................................... A. tristis Schillhammer, 2006 China (Fujian, Guangdong, Jiangxi)

- Segment 10 of antennae twice as long as wide.............. A. atronitidus Schillhammer, 2006 Vietnam, China (Hainan)

8 Pronotum narrower, 1.09–1.12 times as wide as long; apex of median lobe of aedeagus with tiny hook bent toward paramere................................................. A. sphaericollis Schillhammer, 2006 China (widely distributed)

- Pronotum broader, 1.14–1.19 times as wide as long; apex of median lobe of aedeagus without hook....................................................................................... A. matsukii Shibata, 1979 China (Taiwan)

9 Head and pronotum metallic green, elytra black.............. A. atroviridis Schillhammer, 2008 China (Fujian, Guangxi)

- Elytra with metallic hue............................................................................... 10

10 Elytra with rows of larger punctures among ground punctuation.............. A. semiaeneus ( Cameron, 1921) Myanmar

- Elytra with only ground punctation...................................................................... 11

11 Head and pronotum brilliant metallic golden green, clearly contrasting with purplish blue elytra.......................................................................................... A. pergrandis Scheerpelts, 1974 Vietnam

- Entire fore body greenish blue.......................................................................... 12

12 Micropunctation on head and pronotum exceedingly fine, particularly on pronotum visible only at a minimum magnification of 25 times.................................................................................................... A. emeishanus Schillhammer, 2006 China (Sichuan), A. fukienensis Schillhammer, 2006 China (Fujian, Guangxi, Guizhou)

- Micropunctation on head and pronotum clearly visible at 10 times magnification.................................. 13

13 Eyes about 1.3 times as long as tempora.......................... A. jizushanus Schillhammer, 2006 China (Yunnan)

- Eyes at least 1.45 times as long as tempora................................................................ 14

14 Elytra short, distinctly widened posteriorly.................. A. caeruleosplendens Schillhammer, 2021 China (Yunnan)

- Elytra subparallel-sided............................. A. bramlettorum Schillhammer, 2006 Thailand, China (Yunnan)

15 Head and pronotum with isodiametrical microsculpture while elytra without......................................................................................... A. robillardae Schillhammer, 2006 China ( Taiwan, Zhejiang)

- Head and pronotum with isodiametrical microsculpture, elytra with isodiametrical microsculpture, at least in punctural grooves............................................................................................ 16

16 Elytra with dense, almost fossulate punctural grooves....................................................... 17

- Elytra with usual punctation, iso-diametrical microsculpture only appear in punctural grooves, endemic to Xizang, China... .................................................................................................. 18

17 Smaller species (fore body 6.5 mm); eyes about 1.7 times as long as tempora; fore body with slight metallic violaceous hue........................................................... A. rugulipennis Schillhammer, 2006 China (Yunnan)

- Larger (fore body 7.5–8.0 mm long); eyes 1.1–1.3 times as long as tempora; fore body without metallic hue................................................................. A. chinensis Schillhammer, 2006 China (widely distributed)

18 Larger species with fore body 9.2–9.4 mm, tempora conspicuously angulate.................................................................................................... A. tibetanus Schillhammer, 2006 China (Xizang)

- Smallerspecies with fore body 7.7–7.9 mm, tempora rounded.................. A. pseudotibetanus sp. n. China (Xizang)

19 Subbasal elytral ridge extending laterad toward humeral angle, forming sharp plate-like structure at base of elytra................................................................... A. basilineatus Schillhammer, 2017 China (Yunnan)

- Subbasal elytra ridge normal, extending anteriad, or, if extending laterad, vanishing a short distance from scutellum, base of elytra thus without carina.............................................................................. 20

20 Entire elytra covered with sparse, very fine, regularly spaced setiferous punctures................................. 21

- Elytra with posterior half or at least a large roundish area along suture glabrous................................... 22

21 Smaller species with fore body 6.9–8.2 mm, median lobe in lateral view without large tooth....................................................................................... A. hubeiensis Schillhammer, 2006 China (Hubei)

- Larger species with fore body 8.7–8.8 mm, median lobe in lateral view with large tooth................................................................................................... A. daweishanus sp. n. China (Yunnan)

22 Elytra with irregular longitudinal rows of larger punctures............... A. subtilis Schillhammer, 2017 China (Guangxi)

- Elytra with several larger punctures, rarely arranged in a row.................................................. 23

23 Elytral ground punctation more extensive, occupying entire base and lateral third or almost lateral half of each elytron between base and posterior margin, sometimes extending toward suture at posterior margin, leaving only a circular central spot glabrous (doubtful cases key out twice).......................................................................... 24

- Elytral ground punctation distinctly less extensive, elytra either almost entirely glabrous or, if extending toward posterior margin, never occupying more than the dorsolateral fifth or less of the elytral width in front of posterior margin (doubtful cases key out twice).......................................................................................... 28

24 Eyes small, tempora more than 1.5 times as long as eyes; pronotum without any indication of dorsal rows of punctures.................................................................. A. murzini Schillhammer, 2008 China (Yunnan)

- Eyes larger, tempora less than 1.4 times as long as eyes; pronotum with rather irregular, usually asymmetrical, but distinct indication of dorsal rows of punctures.................................................................... 25

25 Paramere with peg setae arranged in two small clusters at about mid-length...................................... 26

- Paramere without peg setae............................................................................ 27

26 Paramere with apex pointed................................. A. fanjingshanus Schillhammer, 2017 China (Guizhou)

- Paramere with apex subtruncate or rounded................... A. leigongshanus Schillhammer, 2008 China (Guizhou)

27 Paramere subparallel-sided, with apex notched..................... A. holzschuhi Schillhammer, 2008 China (Yunnan)

- Paramere concave-sided, with apex rounded to subtruncate or slightly notched.............................................................................................. A. grebennikovi Schillhammer, 2017 China (Sichuan)

28 Eyes larger, tempora about 1.1 times as long as eyes (rarely 1.2)............................................... 29

- Eyes smaller, tempora at least 1.25 times as long as eyes..................................................... 31

29 Paramere with apex rounded...................................... A. reuteri Schillhammer, 2011 China (Guangxi)

- Paramere with apex notched............................................................................ 30

30 Paramere wide, with peg setae arranged in two small clusters................... A. uenoi Hayashi 2011 China (Sichuan)

- Paramere slender, without peg setae........................ A. zhenbaodingensis Schillhammer, 2017 China (Guangxi)

31 Abdomen slender, subparallel between segments III–VII, paratergites narrow................................................................................................ A. ailaoshanus Schillhammer, 2017 China (Yunnan)

- Abdomen broad, with convex outline, widest at about level of segment IV, paratergites broad........................ 32

32 Larger, fore body 8.1–8.7 mm long; eyes smaller, tempora more than 1.4 times as long as eyes, sides of pronotum almost regularly convex, distinctly narrowed toward base................. A. doupengshanus Schillhammer, 2017 China (Guizhou)

- Smaller, fore body usually less than 8 mm long; eyes larger, tempora less than 1.4 times as long as eyes, sides of pronotum subparallel in basal half, hardly narrowed toward base....................................................... 33

33 Pronotum with irregular, asymmetrical, but distinct indication of dorsal rows of punctures (in addition to a pair of larger punctures at anterior margin), often present as seemingly erratic single punctures on each side of midline, usually in anterior half of pronotum................................................. A. grebennikovi Schillhammer, 2017 China (Sichuan)

- Pronotum without any indication of dorsal rows of punctures.................................................. 34

34 Elytra strongly trapezoidal, sharply angled at shoulders............... A. tronqueti Schillhammer, 2006 China (Guangxi)

- Elytra less strongly trapezoidal, shoulders rounded.......................................................... 35

35 Disc of elytra without large setiferous punctures.................. A. kaiserianus ( Bernhauer, 1933) China (Chongqing)

- Disc of elytra with 2 to 4 large setiferous punctures ambiguously arranged in a row sublaterally........................................................................................ A. kuankuoshuiensis sp. n. China (Guizhou)