Neoserica chetaoensis 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 : 364-366

Neoserica chetaoensis Ahrens & Pham , new species

Fig. 2E–H

Type material.. Holotype: ♂ “ VIETNAM, Yen Bai Prov., Mu Cang Chai Distr., Cha Tao [sic!] commune, Mu Cang Chai Species & Habitats Cons. Area , 21.7641N, 104.0430°E, / around Cong Troi ( Gate to Heaven ) Pass , 2040 m, upper montane evergreen forest, at light, 24-29.IX.2016 (#14), Otto Merkl & Phu Pham Van” ( HNHM) . Paratypes: 1 ♂ “ VIETNAM, Yen Bai Prov., Mu Cang Chai Distr., Cha Tao [sic!] commune, Mu Cang Chai Species & Habitats Cons. Area , 21.7641N, 104.0430°E, / around Cong Troi ( Gate to Heaven ) Pass , 2040 m, upper montane evergreen forest, at light, 24-29.IX.2016 (#14), Otto Merkl & Phu Pham Van” ( ZFMK) , 2 ♂♂ “ VIETNAM, Yen Bai Prov., Mu Cang Chai Distr., Che Tao commune, Mu Cang Chai Species & Habitats Cons. Area , 21.7641N, 104.0430°E, / around Cong Troi ( Gate to Heaven ) Pass , 2040 m, upper montane evergreen forest, at light, 24-29.IX.2016 (#14), Otto Merkl & Phu Pham Van” ( IEBR) , 2 ♂♂ “ VIETNAM, Hoang Lien N.P., Lao Cai Province, Sa Pa Town, Tram Ton Pass , light trap, 18.vii.2001 ” ( IEBR) , 2 ♂♂ “Hoang Lien N.P., Lao Cai Province, Sa Pa Town, Tram Ton Pass , light trap, 5.vii.2013 ” ( IEBR) , 1 ♂ “Hoang Lien N.P., Lao Cai Province, Sa Pa Town, Tram Ton Pass , light trap, 26-27.ix.2013 ” ( IEBR) , 1 ♂ “ Copia Nature Reserve, Thuan Chau , Son La Province, light trap, 28.ix.2016 ” ( IEBR) , 6 ♂♂ “ Coll. I.R.Sc. N.B. Vietnam, Hoang Lien N.P. 22°21’00’’N, 103°46’20’’E 1-5.vii.2013 light trap Leg. J. Constant & J. Bresseel, I.G.: 32.454” ( ISNB) , 1 ♂, 1 ♀ “ THAILAND, N: Chang Mai Prov. Doi Pha Hom Pok, 20.-26.II.2004 leg. T. Ihle ” ( ZFMK) .

Description of the holotype. Body length: 5.4 mm, length of elytra: 4.1 mm, width: 3.3 mm. Body oval, yellowish brown, elytra dark brown, antennal club yellowish, dorsal surface dull and except frons nearly glabrous, labroclypeus and anterior two thirds of frons moderately shiny.

Labroclypeus subtrapezoidal, little wider than long, widest at base; lateral margins moderately convex and convergent towards moderately rounded anterior angles; anterior margin weakly emarginate medially; margins weakly reflexed; surface strongly elevated medially and shiny, finely and densely punctate, with a few single setae anteriorly. Frontoclypeal suture finely incised, not elevated but curved. Smooth area anterior to eye weakly convex, 1.5 times as wide as long. Ocular canthus moderately long and narrow (equal to 1/3 of ocular diameter), impunctate, with a single terminal seta. Frons on anterior half shiny (without dull toment), finely and irregularly densely punctate, with a few long single setae beside eyes, otherwise glabrous; on posterior half dull (with toment), finely and very densely punctate, with dense, short setae. Eyes small, ratio diameter/interocular width: 0.53. Antenna with ten antennomeres, club with three 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 but evenly convex, well-convergent anteriorly; anterior angles produced and nearly rectangular, weakly rounded at tip; posterior angles moderately rounded; anterior margin straight, with a fine marginal line; surface moderately densely and coarsely punctate, with minute setae in punctures; lateral and anterior border densely setose; basal margin without marginal line; hypomeron distinctly carinate basally. Scutellum long, with fine, dense punctures, and minute setae in punctures, without smooth area at base.

Elytra short-oval, widest at posterior third; striae weakly impressed, finely and moderately densely punctate; intervals moderately convex, with sparse, fine punctures concentrated along striae, with minute setae in punctures. 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: 1/1.37. Pygidium weakly convex and dull, sparsely punctate, without smooth midline, with a few 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, without punctures dorsally; metatarsomere 1 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. 2E–G . Habitus: Fig. 2H .

Variation. Length: 5.6–6.0 mm; elytral length: 4.3–4.5 mm; width: 3.5–3.6 mm. Female: eyes as large as in male, antennal club short and composed of three lamellae, little shorter than remaining antennomeres combined; pygidium flat.

Diagnosis. Neoserica chetaoensis Ahrens & Pham , new species differs from N. anonyma Liu, Fabrizi, Bai, Yang & Ahrens, 2014 , which is similar in the shape of the aedeagus, by the yellowish brown elytra, by the antennal club in male being composed of only three antennomeres, and by the distinctly longer parameres.

Etymology. The new species is named after its type locality, Che Tao (adjective in nominative singular case). Some labels have an incorrect spelling of the type locality (i.e., Cha Tao).

Figures

FIGURE 2. A–D: Neoserica fragilis Ahrens & Pham, new species (holotype); E–H: N. chetaoensis Ahrens & Pham, 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.