Neoserica diplospinosa Ahrens & Pham, 2021

Ahrens, Dirk & Pham, Phu Van, 2021, Additions to the Neoserica calva group from continental South East Asia (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5032 (3), pp. 357-378 : 367-368

Neoserica diplospinosa Ahrens & Pham , new species

Fig. 3E–H

Type material. Holotype: ♂ “ Coll. I.R. Sc. N.B. Vietnam: Tam Dao N.P. 25-28-VIII-2010 / Light Trap Leg. J. Con- stant & P. Limbourg I.G.31.668 / 1098 Sericini Asia spec.” ( ISNB) . Paratypes: 2 ♂♂ “ Coll. I.R. Sc. N.B. Vietnam: Tam Dao N.P. 25-28-VIII-2010 / Light Trap Leg. J. Constant & P. Limbourg I.G.31.668” ( ISNB, ZFMK) , 3 ♂♂ “N. Vietnam: Vinh Phu prov. Tam Dao 900 m. 1.XI.1963 leg. O. Kabakov ” ( ZIN, ZFMK) , 1 ♂ “N. Vietnam: Vinh Phu prov. Tam Dao 900 m. 30.VIII.1963 leg. O. Kabakov ” ( ZFMK) .

Description of the holotype. Body length: 7.1 mm, length of elytra: 5.1 mm, width: 4.4 mm. Body oval, dark brown, labroclypeus and legs reddish brown, antennal club yellowish brown, dorsal surface dull and except frons nearly glabrous, labroclypeus and anterior two thirds of frons shiny.

Labroclypeus subtrapezoidal, little wider than long, widest at base; lateral margins convex and convergent towards moderately rounded anterior angles; anterior margin weakly emarginate medially; margins weakly reflexed; surface convexly elevated medially and shiny, finely and densely punctate, with a few single setae anteriorly. Frontoclypeal suture distinctly incised, slightly elevated and bent medially. Smooth area anterior to eye small, weakly convex, twice as wide as long. Ocular canthus moderately long and narrow (equal to 1/3 of ocular diameter), finely and sparsely punctate, with a single terminal seta. Frons on anterior two thirds shiny, finely and irregularly, moderately densely punctate, with a few long single setae beside eyes, otherwise glabrous; on posterior third dull (with toment), finely and sparsely punctate, with a few fine, short setae. Eyes moderately large, ratio diameter/interocular width: 0.72. Antenna with ten antennomeres, club with four antennomeres and straight, as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly. Labrum transverse, short, not produced medially, with weak median sinuation.

Pronotum subtrapezoidal, widest at base; lateral margins weakly evenly convex, convergent anteriorly; anterior angles strongly produced and sharp; posterior angles blunt; anterior margin weakly convex, with a fine marginal line; surface densely and finely punctate, with minute setae in punctures; lateral and anterior sparsely setose; basal margin without marginal line; hypomeron distinctly carinate basally. Scutellum short, with fine, very dense punctures, and minute setae in punctures, on basal midline impunctate.

Elytra short, widest at posterior third; striae weakly impressed, finely and moderately densely punctate; intervals weakly convex, with sparse, fine punctures concentrated along striae, impunctate medially, with minute setae in punctures; penultimate lateral interval with numerous erect long setae. Epipleural edge fine, ending at moderately curved external apical angle of elytra; epipleura densely setose; apical border with a fine rim of microtrichomes (visible at 100x magnification).

Ventral surface dull, finely and densely punctate. Metasternum except long setae on disc nearly glabrous, sparsely covered with minute setae in punctures. Metacoxa glabrous, with a few single setae laterally. Abdominal sternites finely and densely punctuate, glabrous except minute setae in punctures, with a transverse row of coarse punctures each bearing a robust long seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.36. Pygidium strongly convex and dull, sparsely punctate, without smooth midline, with numerous long setae on apical half.

Legs moderately slender. Femora with two longitudinal rows of setae, finely and sparsely punctate. Metafemur dull and sparsely finely punctate; anterior margin acute, behind anterior margin without serrated line; posterior margin in apical half serrated ventrally and moderately widened at apex; posterior margin finely serrated dorsally, glabrous. Metatibia moderately slender and short, widest at apex, ratio of width/length: 1/3.2; dorsal margin sharply carinate, with two groups of spines; basal group at middle, apical group at three quarters of metatibial length; in basal half with a few short robust setae in single robust punctures with serrated margin; external face longitudinally convex, finely and sparsely punctate; ventral margin finely serrated, with three robust setae, with the apical one being more distant; medial face impunctate, glabrous, apex bluntly truncate interiorly near tarsal articulation. Tarsomeres ventrally with sparse, short setae, not carinate laterally, with fine sparse punctures dorsally; metatarsomere 1 almost twice as long as dorsal metatibial spur and as long as following two tarsomeres combined. Protibia moderately long, bidentate, bluntly widened laterally before basal tooth; anterior claws symmetrical, basal tooth of inner claw sharply truncate at apex.

Aedeagus: Fig. 3E–G . Habitus: Fig. 3H .

Female unknown.

Variation. Length: 7.0– 8.1 mm; elytral length: 5.2–5.8 mm; width: 4.5–5.2 mm.

Diagnosis. Neoserica diplospinosa Ahrens & Pham , new species differs from N. pingbianensis Ahrens, Fabrizi & Liu, 2019 by the parameres being subequal in length, the strongly asymmetric phallobase, and the right paramere being strongly bent externally at middle.

Etymology. The name of the new species is derived from the combined Greek prefix diplo - (bifold) and spinosa (spinose), with reference on the bi-spinose shape of the left paramere.

Figures

FIGURE 3. A–D: Neoserica allosigillata Ahrens & Pham, new species (holotype); E–H: N. diplospinosa Ahrens & Pham, new species (holotype); I–M: N. tramton Ahrens & Pham, new species (holotype). A, E, I: Aedeagus, left side lateral view; C, G, L: Aedeagus, right side lateral view; B, F, K: Parameres, dorsal view; J: aedeagus, dorsal view; D, H, M: Habitus (not to scale). Scale: 0.5 mm.