Helioserica, 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 : 9-10

Gastroserica (sbg.) Helioserica Ahrens, Lukic & Liu, new subgenus

Type species of the new subgenus: Microserica varians Moser, 1915 (by current designation).

Diagnosis. The new subgenus differs from its sister clade ( Fig. 1 ), Gastroserica sensu stricto, by the well-produced and distinctly angled anterior angles of pronotum, as well as by the distinctly emarginated anterior margin of labroclypeus. Furthermore, the apical abdomen is not as robustly developed as in most Gastroserica sensu stricto species, with the pygidium barely protruding under the apex of elytra.

Remarks. Given, of being the sister lineage of Gastroserica ( Fig. 1 ; see also Eberle et al. 2017), and thus representing a monophyletic group with the species of Gastroserica sensu stricto, we nevertheless decided to erect a new and separate subgenus for these species, since key diagnostic features of Gastroserica sensu stricto are not present among these species, namely the obsolete anterior angles of pronotum and the straight, non-emarginate anterior margin of labroclypeus.

All species so far classified as Gastroserica ( Ahrens & Bezděk 2016) are subsequently assigned to the subgenus Gastroserica Brenske, 1897 .

Etymology. The name of the new subgenus is composed of the Greek word “ helios ” (sun) and the word root Serica (type genus of the tribe Sericini ), with reference to the diurnal activity of the species of this subgenus.

Key to the species of the Gastroserica ( Helioserica new subgenus) (♁♁):

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

- Dorsal surface completely simply shiny................................................................... 14

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

4 Left distal portion of phallobase strongly widened (lateral view)............................ G. 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. 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. 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. yuebaensis Ahrens, Lukic & Liu, new species

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. fumaria Ahrens, Lukic & Liu, new species

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

10 Right paramere in basal two thirds strongly widened........................................................ 11

- Right paramere in basal half not particularly widened..................................... G. varians ( Moser, 1915)

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

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

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

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

13 Elytra colour yellow to dark brown. Basal lobe of left paramere short.......................... G. fukiensis Frey, 1972

- Elytra colour blackish, pronotum reddish. Basal lobe of left paramere long..................................................................................................... G. simaoensis Ahrens, Lukic & Liu, new species

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

- Phallobase ventrally without prominent lateral elevations..................................................... 19

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

- Prominent lateral elevations of phallobase at middle......................................................... 17

16 Right paramere more than half as long as phallobase. Eyes moderately large, ratio diameter/interocular width: 0.64................................................................. G. piceocoerulea Ahrens, Lukic & Liu, new species

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

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

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

18 Dorsal/basal lobe shorter than the ventral one, sharply pointed, simple......... G. ivoi Ahrens, Lukic & Liu, new species

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

19 Left paramere with a distinct and subequal ventral and dorsal lobe....... G. rubropicea Ahrens, Lukic & Liu, new species

- Left paramere without a ventral and dorsal lobe, the latter basally reduced in length and developed short and medially.................................................................... G. bannok Ahrens, Lukic & Liu, new species

Figures

FIGURE 1. Phylogenetic placement of lineages so far assigned to Microserica (and some of its closest relatives) according to the phylogeny of Eberle et al. (2017).