Oxyserica marginata (Brenske, 1896) Ahrens & Liu & Lukic & Bai, 2023

Ahrens, Dirk, Liu, Wangang, Lukic, Daniel & Bai, Ming, 2023, A taxonomic review of Microserica Brenske, 1894 from continental Asia (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5241 (1), pp. 1-115 : 71-72

Oxyserica marginata group

Key to species of the Oxyserica marginata group (♁♁):

1 Antennal club with three antennomeres.................................................. O. elegans ( Frey, 1975)

- Antennal club with more than three antennomeres............................................................ 2

2 Antennal club with six antennomeres...................................................................... 3

- Antennal club with four or five antennomeres............................................................... 4

3 Metatibia moderately wide, ratio width/length: 1/3.2. Parameres nearly symmetrical......... O. pedongensis ( Ahrens, 1998)

- Metatibia wide, ratio width/length: 1/2.8. Parameres asymmetrical...................... O. marginata ( Brenske, 1896)

4 Antennal club with four antennomeres..................................................................... 5

- Antennal club with five antennomeres.................................................................... 16

5 Metatarsomere one as long as dorsal metatibial spine........................................................ 10

- Metatarsomere one distinctly longer than dorsal metatibial spine................................................ 6

6 Species from Himalaya................................................................................ 11

- Species from Yunnan and Myanmar....................................................................... 7

7 Specimen large, size> 7.2 mm. Metatibia long and narrow, ratio width/length: 1/3.5............................................................................................ O. bifascipennis Ahrens, Lukic & Liu, new species

- Specimen small, size <5.5 mm. Metatibia sorter, ratio width/length <1/3.0........................................ 8

8 Body stouter and shorter. Elytra with a single lateral dark spot.............. O. serena Ahrens, Lukic & Liu, new species

- Body more elongate. Elytra with on lateral dark spot behind middle, and one near suture on anterior quarter.............. 9

9 Dorsal lobe of left paramere exceeds the external margin of the right paramere, strongly curved backwards again towards the left side of phallobase......................................................... O. nigropicta ( Fairmaire, 1891)

- Dorsal lobe of left paramere developed basally and distally, not exceeding the external margin of the right paramere................................................................................... O. diversicornis ( Moser, 1915)

10 Body bi-colored, elytra yellowish brown with dark suture. Body oblong. Lateral margins of pronotum in basal half parallel.................................................................................. O. steelei (Ahrens, 2004)

- Body unicoloured. Body short oval................................................... O. pruinosa ( Hope, 1831)

11 Metatibia short and wide, ratio width/length: 1/2.5.......................................................... 12

- Metatibia narrower, ratio width/length: <1/3.0............................................................. 14

12 Pronotum yellowish brown, with two dark spots. Elytra with distinct cross-like signature..... O. cechovskyi ( Ahrens, 1999)

- Pronotum dark, at maximum with light lateral margins. Elytra unicoloured black, brown, or yellowish brown with dark margins............................................................................................ 13

13 Apical lobe of right paramere long.................................................. O. truncata ( Brenske, 1898)

- Apical lobe of right paramere short................................................. O. bhutanensis ( Frey, 1975)

14 Antennal club 1.5 times as long as remaining antennomeres combined. Metatibia narrow, ratio width/length: 1/3.8....... O. hispidula ( Frey, 1975)

- Antennal club twice as long as remaining antennomeres combined and slightly reflexed. Metatibia wider, ratio width/length: 1/3.0–3.3........................................................................................... 15

15 Phallobase with a distinct dorsal sinuation before apex (lateral view)..................... O. myagdiana ( Ahrens, 1998)

- Phallobase without dorsal sinuation before apex (lateral view)......................... O. gandakiensis ( Ahrens, 1998)

16 Metatibia short and wide, ratio width/length: 1/2.5–2.8....................................................... 17

- Metatibia narrower, ratio width/length: 1/3.2.......................................... O. martensi ( Ahrens, 1998)

17 Basal lobe of left paramere as long as paramere itself........................................................ 18

- Basal lobe of left paramere distinctly shorter than paramere itself.............................................. 19

18 Right paramere rounded at apex, left paramere short.................................. O. schawalleri ( Ahrens, 1998)

- Right paramere truncate at apex and bluntly toothed, left paramere as long as right one........ O. arunensis ( Ahrens, 1998)

19 Left paramere with a lateral somewhat reflexed tooth................................. O. interrogator (Arrow, 1946)

- Left paramere without lateral tooth.................................................. O. schulzei ( Ahrens, 1998)