Serica ventrituberculata Ahrens, Fabrizi & Liu, 2022

Ahrens, Dirk, Fabrizi, Silvia, Bai, Ming & Liu, Wangang, 2022, Taxonomic revision of Serica MacLeay, 1819 (sensu lato) from China and adjacent areas (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), with updates on Nipponoserica Nomura, 1972, Zootaxa 5186 (1), pp. 1-83 : 56-58

Serica ventrituberculata Ahrens, Fabrizi & Liu , new species

Figures 14E–H , 23

Type material examined. Holotype: ♂ “ Guance Zhan, Wuyipeng, Wolongzhen , Sichuan, 24.VII.2004, 2560m, leg. Zhang Yong ” ( IZAS) . Paratypes: 1 ♂, 1 ♀ “ Ebian County, 25.VI.1981, leg. Shan Shigui” ( IZAS) , 1 ♂ “ Mts. Maoershan , Guangxi, 14.VII.1985, 1900m, leg. Liao Subai ” ( IZAS) , 1 ♂ “ Wolong Guangou, Wolong , Sichuan, 20.VII.2004, 2150m, light trap, leg. Zhang Yong ” ( IZAS) .

Description of the holotype. Length: 9.4 mm, length of elytra: 7.1 mm, width: 5.1 mm. Body elongate eggshaped, dark reddish brown, partly with greenish toment, elytra with dark spots, even intervals almost completely dark, antenna yellowish, legs brown; dorsal surface dull and densely covered with short yellow setae being bent posteriorly.

Labroclypeus subtrapezoidal, distinctly wider than long, widest at base, lateral margins convex and strongly convergent anteriorly, anterior angles acute; anterior margin deeply and widely emarginate medially; margins weakly reflexed; surface flat and shiny, finely and densely punctate, finely densely setose, behind anterior margin glabrous; frontoclypeal suture finely incised, weakly convex; smooth area anterior to eye large and flat, as wide as long; ocular canthus moderately long and slender (1/3 of ocular diameter), with a few fine punctures bearing each a short seta. Frons completely dull and flat, with fine and very dense punctures, evenly covered with short yellow setae being bent backwards and longer erect setae. Eyes small, ratio diameter/ interocular width: 0.5. Antenna with ten antennomeres; antennomeres three to five slightly wider than long, antennomere six and seven transverse and short; club with three antennomeres, 1.1 times as long as remaining antennomeres combined and straight. Mentum weakly elevated, anteriorly flattened. Labrum transverse, short, strongly produced along the middle, moderately emarginate medially.

Pronotum subtrapezoidal, widest shortly before base, lateral margins evenly convex and strongly convergent anteriorly; anterior angles distinctly produced and acute; posterior angles strongly rounded; anterior margin medially with a fine marginal line and very weakly produced medially; surface densely and coarsely punctate, with dense short yellow setae bent posteriorly; lateral margins sparsely setose; hypomeron carinate at base, weakly produced ventrally. Scutellum large, triangular, finely and very densely punctate, basal midline smooth, pilosity as in lateral pronotum.

Elytra oval, widest at middle, striae indistinctly impressed, finely and densely punctate; intervals flat, with fine, very dense punctures; dark spots impunctate or with less dense punctures, with fine, short pilosity as in pronotum, without longer, erect setae; epipleural edge fine, ending at moderately curved external apical angle of elytra, epipleura densely setose, apical margin with a very fine membranous rim composed of minute microtrichomes (magnification 100x).

Ventral surface dull, finely and densely punctate, including metacoxa and abdominal sternites densely shortly setose; abdominal sternites with a transverse row of coarse punctures, each bearing a long seta, otherwise shortly setose as rest of ventral surface; ultimate sternite at middle 1.5 times as long as penultimate one. Mesosternum between mesocoxae half as wide as the slender mesofemur. Ratio of length of metepisternum/ metacoxa: 1/ 1.38. Pygidium moderately convex and dull, finely and densely punctate, smooth midline narrow, with dense short setae.

Legs slender; femora with two longitudinal rows of setae, coarsely and densely punctate between the rows, with robust setae on basal half; metafemur shiny, anterior margin acute, without a continuously serrated line behind anterior edge, posterior margin ventrally serrated in apical half and not widened, dorsal posterior margin completely serrated, in basal half with a few long setae which are half as long as width of metafemur. Metatibia slender and long, widest shortly before apex, ratio of width/ length: 1/ 4.6, dorsally sharply carinate, with two groups of spines, basal group shortly before middle, apical group at three quarters of metatibial length, basally with a few single, robust setae; external face impunctate, with dense superficial longitudinal wrinkles; ventral margin serrated, with two very widely separated robust setae; medial face glabrous and smooth; apex interiorly near tarsal articulation concavely truncate. Tarsomeres ventrally with sparse, minute setae, dorsally smooth. Metatarsomeres ventrally glabrous, laterally and dorsally carinate, with a strongly serrated ridge ventrally; first metatarsomere as long as following two tarsomeres combined and almost twice as long as dorsal tibial spur; mesotarsomeres not carinate. Protibia moderately long, bidentate, external margin serrate, with a few small teeth at base, anterior claws symmetrical, basal tooth of inner claw bluntly truncate as the external one.

Aedeagus: Fig. 14E–G . Habitus: Fig. 14H .

Diagnosis. Serica ventrituberculata Ahrens, Fabrizi & Liu , new species differs from S. bicornis Ahrens, 2005 by the shape of parameres: the right paramere is almost straight (lateral view) and the left paramere has its lateral tooth almost at middle rather than before apex, the basal portion is almost twice as wide as the dorsal one (while it is almost subequal in width in S. bicornis ); the phallobase is dorsally without tubercles, but instead it has ventrally before apex a pair of robust tubercles.

Etymology. The name of the species (adjective in nominative case singular) is derived from the combined Latin words ‘ ventris ’ (venter) and ‘ tuberculatus ’ (i.e., having tubercles), with reference on the two ventral tubercles of phallobase.

Variation. Length: 8.1–10.0 mm, length of elytra: 6.5–7.6 mm, width: 4.5–5.1 mm. Female: antennal club short, little shorter than remaining antennomeres combined; pygidium at apex strongly convex; eyes as large as in male.

Key to species of Serica nigroguttata group (♂) (from Ahrens 2007, extended):

1 Pilosity of elytra fine, long and dense. Median apical sinuation of phallobase partially sclerotized and with a pointed lamella................................................................................ S. subpilosa Ahrens, 2007

- Pilosity of elytra short and moderately dense or sparse........................................................ 2

2 Anterior margin of labroclypeus medially deeply sinuated..................................................... 3

- Anterior margin of labroclypeus medially moderately sinuated................................................. 9

3 Pilosity of metasternum seta-like......................................................................... 4

- Pilosity of metasternum scale-like........................................................................ 6

4 Antennal club shorter than remaining antennomeres combined. Parameres short, less than half as long as phallobase............................................................................. S. brevitarsis (Kobayashi & Yu, 1993)

- Antennal club longer shorter than remaining antennomeres combined. Parameres long, about half as long as phallobase.... 5

5 Anterior angles of pronotum rounded in the tip. Protarsal claws asymmetrical, basal lobe of inner claw truncated sharply..................................................................................... S. jindrai Ahrens, 2007

- Anterior angles of pronotum sharply pointed. Protarsal claws symmetrical...................... S. wrasei Ahrens, 2007

6 Antennal clavus twice as long remaining antennomeres combined.......................... S. inaequalis Ahrens, 2007

- Antennal clavus as long or little longer than remaining antennomeres combined.................................... 7

7 Anterior angles of pronotum distinctly protruding. Apex of both parameres straight............... S. tryznai Ahrens, 2007

- Anterior angles of pronotum weakly protruding............................................................. 8

8 Apex of left paramere hook-like and curved externally, dorsomedian margin of left paramere simple. Right paramere apically simply narrowed. ............................................................ S. parasquamosa Ahrens, 2007

- Apex of left paramere indistinct and fusing with the sclerotized ventral membrane, without hook, dorsomedian margin of left paramere with a robust internal tooth at middle of paramere length. Right paramere apically widened, with blunt lateral angulation at apex..................................................... S. yuheba Ahrens, Fabrizi & Liu , new species

9 Dorsomedian apical sinuation of phallobase concave and deeply sinuated........................................ 10

- Dorsomedian apical sinuation of phallobase partially sclerotized and with a sharply pointed lamella................... 15

10 Antennal club distinctly longer than remaining antennomeres combined. Long and scale-like setae on elytra are erect. Preapical dark spot on elytra indistinct. .......................................................... S. lagoi Ahrens, 2007

- Antennal club almost no longer than remaining antennomeres combined. Long and scale-like setae on elytra are adpressed or directed posteriorly................................................................................... 11

11 Metacoxa laterally just with fine setae.................................................................... 12

- Metacoxa laterally with numerous white scales.......................................... S. maculosa Moser, 1915

12 Pronotum in basal half strongly narrowed anteriorly. Protarsal claws symmetrical.............. S. squamosa Ahrens, 2007

- Pronotum in basal half very weakly or not narrowed anteriorly................................................ 13

13 Left paramere uniformly narrowed distally................................................................ 14

- Left paramere preapically medially strongly widened and distally abruptly narrowed......... S. feisintsiensis Ahrens, 2007

14 Base of clypeus just setose............................................................ S. pulvinosa Frey, 1972

- Base of clypeus with small white scales............................................ S. nigroguttata Brenske, 1897

15 Phallobase in lateral view simply pointed apically........................................................... 16

- Phallobase in lateral view with a long and more or less robust ventroapical lamella................................. 18

16 Right paramere curved................................................................................ 17

- Right paramere completely straight. Phallobase beside dorsomedian apical sinuation on each side with a blunt tubercle...................................................................................... S. horrida Ahrens, 2007

17 Right paramere strongly curved, without preapical lateral teeth. ......................... S. latesquamata Ahrens, 2007

- Right paramere weakly curved, with robust, preapical lateral teeth......... S. baoshan Ahrens, Fabrizi & Liu , new species

18 Protarsal claws symmetrical, basal tooth of inner claw simply pointed. ...................... S. sinuaticeps Moser, 1915

- Protarsal claws asymmetrical, basal tooth of inner claw small and lobiform..................... S. werneri Ahrens, 2007

Figures

FIGURE 14. A–D: Serica emaw Ahrens, Fabrizi & Liu, new species (holotype); E–H: S. ventrituberculata Ahrens, Fabrizi & Liu, new species (holotype). A, E: Aedeagus, left side lateral view; C, G: Aedeagus, right side lateral view; B, F: Parameres, dorsal view; D, H: Habitus (not to scale). Scale: 0.5 mm.

FIGURE 23. Distribution of Serica allotengchongana Ahrens, Fabrizi & Liu, new species, S. baishuitaiensis Ahrens, Fabrizi & Liu, new species, S. emaw Ahrens, Fabrizi & Liu, new species, S. excisa Frey, 1972, S. huangbaiyuanensis Ahrens, Fabrizi & Liu, new species, S. paralupina Ahrens, Fabrizi & Liu, new species, S. tengchongana Ahrens, Fabrizi & Liu, new species, S. ventrituberculata Ahrens, Fabrizi & Liu, new species .