Gastroserica (Helioserica), 2023

Ahrens, Dirk & Pham, Phu, 2023, Updates on the taxonomy and distribution of Gastroserica Brenske, 1897, Microserica Brenske, 1894, and Moronoserica Ahrens, Lukic & Liu, 2023 (Coleoptera: Scarabaeidae: Sericinae: Sericini), Zootaxa 5346 (5), pp. 551-566 : 555-556

Updated key to Gastroserica (Helioserica) species (males only):

1 Dorsal surface mostly dull or dull-iridescent................................................................ 2

- Dorsal surface completely simply shiny, or shiny-iridescent................................................... 15

2 Elytra with multiple dark spots and darker striae....................................... G. (H.) cognata (Frey, 1972)

- Elytra without multiple dark spots and striae of the same colour as intervals....................................... 3

3 Left paramere with a distinct basal lobe.................................................................... 4

- Left paramere without a distinct basal lobe......................................... G. (H.) quateorum (Frey, 1972)

4 Left, distal portion of phallobase strongly widened (lateral view)........................ G. (H.) hiulca (Brenske, 1897)

- Distal portion of phallobase at both sides narrowed towards apex (lateral view)..................................... 5

5 Left paramere bilobed in distal part....................................................................... 6

- Left paramere simple in distal part (with just one lobe or branch)............................................... 8

6 Phallobase with a ventral lamellose extension on the left side.................................................. 7

- Phallobase without a ventral lamellose extension on the left side..................... G. (H.) bisignata (Nomura, 1974)

7 Left paramere robust, as wide as apical phallobase. Both distal lobes of left paramere subequal in length to the right paramere................................................................. G. (H.) nitidipyga (Nomura, 1974)

- Left paramere narrower, distinctly more narrow than apical phallobase. External distal lobes of left paramere half of length to the right paramere............................................... G. (H.) yuebaensis Ahrens, Lukic & Liu, 2023

8 Right side of apical phallobase with a small granulate raster area................................................ 9

- Right side of apical phallobase without a granulate raster area................................................. 10

9 Left paramere basally wider (lateral view). Right paramere before apex almost straight............................................................................................... G. (H.) fumaria Ahrens, Lukic & Liu, 2023

- Left paramere basally more narrow (lateral view). Right paramere before apex strongly bent externally.............................................................................. G. (H.) phukradung Ahrens, Lukic & Liu, 2023

10 Right paramere in basal two thirds strongly widened (lateral view)............................................. 12

- Right paramere in basal half not particularly widened (lateral view)............................................. 11

11 Right paramere more than half as long as phallobase. Basal lobe of long left paramere much shorter than the rest of the paramere..................................................................... G. (H.) varians (Moser, 1915)

- Right paramere half as long as phallobase. Basal lobe of short left paramere as long as the rest of the paramere............................................................................. G. (H.) horii Ahrens & Pham , new species

12 Left paramere ventrally strongly excavated and bent......................................................... 13

- Left paramere ventrally not excavated and straight....................... G. (H.) roingensis (Fabrizi & Ahrens, 2016)

13 Right paramere at apex strongly bent externally (dorsal view).................................................. 14

- Right paramere at apex weakly bent externally (dorsal view)................. G. (H.) dohertyi (Ahrens & Fabrizi, 2009)

14 Elytra colour yellow to dark brown. Basal lobe of left paramere short...................... G. (H.) fukiensis Frey, 1972

- Elytra colour blackish, pronotum reddish. Basal lobe of left paramere long... G. (H.) simaoensis Ahrens, Lukic & Liu, 2023

15 Phallobase ventrally with prominent lateral elevations....................................................... 16

- Phallobase ventrally without prominent lateral elevations..................................................... 20

16 Prominent lateral elevations of phallobase at apex.......................................................... 17

- Prominent lateral elevations of phallobase at middle......................................................... 18

17 Right paramere more than half as long as phallobase. Eyes moderately large, ratio diameter/interocular width: 0.64................................................................... G. (H.) piceocoerulea Ahrens, Lukic & Liu, 2023

- Right paramere less than half as long as phallobase. Eyes very large, ratio diameter/interocular width: 0.93.................................................................................... G. (H.) loei Ahrens, Lukic & Liu, 2023

18 Left paramere with a distinct and subequal ventral and dorsal/basal lobe......................................... 19

- Left paramere without a ventral and dorsal/basal lobe, the latter basally reduced in length and developed short and medially..................................................................... G. (H.) lucens (Ahrens & Fabrizi, 2009)

19 Dorsal/basal lobe shorter than the ventral one, sharply pointed, simple........... G. (H.) ivoi Ahrens, Lukic & Liu, 2023

- Dorsal/basal lobe as long as the ventral one, rounded at apex, tubuliform with a membranous opening at median apex............................................................... G. (H.) lucidomarginalis Ahrens, Lukic & Liu, 2023

20 Left paramere with a distinct and subequal ventral and dorsal lobe, dorsal (=basal) lobe directed distally............................................................................... G. (H.) rubropicea Ahrens, Lukic & Liu, 2023

- Left paramere dorsal lobe shorter and developed medially.................................................... 21

21 Right paramere straight (lateral view), widened at apex (dorsal view). Basal lobe of left paramere mesobasally directed..................................................................... G. (H.) bannok Ahrens, Lukic & Liu, 2023

- Right paramere weakly curved ventrally (lateral view), not widened at apex (dorsal view). Basal lobe of left paramere mesally directed......................................................... G. (H.) kachin Ahrens & Pham , new species