Tetraserica gialaiensis Pham & Ahrens, 2023

Ahrens, Dirk, Lukic, Daniel, Pham, Phu, Li, Wei & Liu, Wangang, 2023, Tetraserica Ahrens, 2004 of continental Southeast Asia: new records, new species and an updated key to species (Coleoptera: Scarabaeidae: Sericinae: Sericini), Zootaxa 5374 (4), pp. 451-486 : 464-465

Tetraserica gialaiensis Pham & Ahrens , new species

Fig. 5A–D

Type material examined. Holotype: ♂ “[ Vietnam] Gia Lai Pro., Kon Ka Kinh NP, 28.iv.2022; light trap; 14,29675N 108,44949E; 578 m a.s.l.; P.V. Pham leg.” ( IEBR) . Paratype: 1 ♂ “ Myanmar: Sagaing Division Alaungdaw Kathapa NP 22°19.113’N 94°28.518’E 3.- 13.5.2003, ca. 350m, light leg. Boukal & Schillhammer/ 1319 Asia Sericini spec.” ( NHMW) .

Description of the holotype. Length: 8.4 mm, length of elytra: 6.8 mm, width: 5.1 mm. Body oval, dark brown, labroclypeus and dorsal surface glabrous, without setae.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins weakly convex, anterior margin shallowly emarginate medially, anterior angles strongly convex, lateral margin and ocular canthus producing a blunt angle, margins moderately reflexed; surface moderately convex medially, coarsely and moderately densely punctate, without setae; frontoclypeal suture moderately impressed and moderately angled medially; smooth area in front of eye approximately twice as wide as long; ocular canthus moderate and triangular (1/2.5 of ocular diameter), weakly punctate, with one terminal seta. Frons weakly shiny and punctate, bearing only a few erect setae beside eyes. Eyes moderately small, ratio of diameter/ interocular width: 0.52. Antenna yellowish brown, with ten antennomeres, club in male with four antennomeres, as long as remaining antennomeres combined, first joint of club slightly shorter than club. Mentum anteriorly weakly elevated and weakly convex in middle.

Pronotum transverse, widest just before base, lateral margins moderately convex and evenly convergent anteriorly; anterior angles distinctly produced, posterior angles strongly convex. Anterior margin almost straight medially, with a fine, complete marginal line. Surface densely and finely punctate, with minute setae in punctures; lateral margins sparsely setose. Hypomeron not carinate. Scutellum triangular, with fine and dense punctures.

Elytra oblong, widest at posterior third, striae moderately impressed, finely and densely punctate; intervals moderately convex, with fine, dense punctures, glabrous, except minute setae in punctures; epipleural edge robust, ending at convex external apical angle of elytra, epipleura robustly sparsely setose, apical border membraneous, with a fine rim of short microtrichomes.

Ventral surface dull, reddish brown, thorax moderate and dense punctures, sparsely setose, metasternum sparsely covered with fine, short, or minute setae; metacoxa glabrous, with a few single setae laterally; abdominal sternites finely and densely punctate, with a transverse row of coarse punctures each bearing a robust seta. Mesosternum between mesocoxae wider than mesofemur. Ratio of length of metepisternum/ metacoxa: 1/2.0. Pygidium moderately convex and dull, coarsely densely punctate, without smooth midline.

Legs moderately wide; metafemur moderately shiny, anterior margin acute, lacking an adjacent serrated line; ventral posterior margin nearly straight and smooth, slightly widened in apical half; dorsal posterior margin smooth, without setae basally. Metatibia moderately short, widest at middle, ratio width/ length: 1/ 3.3; dorsal margin longitudinally convex, with two groups of spines, basal one at about first third, apical one at nearly two thirds of metatibial length; lateral face smooth, sparsely finely punctate; ventral margin finely serrate, with four robust setae; medial face smooth; apex interiorly near tarsal articulation slightly concave. Tarsomeres in distal half with fine, dense setae ventrally, dorsally smooth; metatarsomeres ventrally with a strong serrated ridge and glabrous, first metatarsomere shorter than following two tarsomeres combined and longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws sharp at apex.

Aedeagus. Fig. 5A–C . Habitus: Fig. 5D . Female unknown.

Diagnosis. Tetraserica gialaiensis Pham & Ahrens , new species differs from the similar T. ruiliensis Liu, Fabrizi, Bai, Yang & Ahrens, 2014 by the distinctly shorter (compared to the length of phallobase) and more robust left paramere (lateral view), which is also at apex curved more strongly, and by the longer apical portion (distal to the strong bent at middle) which is subequal in length to the basal portion (shorter than the basal portion in T. ruiliensis ). From Tetraserica semiruiliensis Fabrizi, Dalstein & Ahrens, 2019 and T. pseudoruiliensis Fabrizi, Dalstein & Ahrens, 2019 , T. gialaiensis Pham & Ahrens , new species differs by the strongly bent right paramere, whose apical portion (distal to the strong bent at middle) is subequal in length to the basal portion (basal to the strong bent) (lateral view).

Variation. Length: 8.4–8.5 mm, length of elytra: 6.8–6.9 mm, width: 5.1–5.2 mm.

Etymology. This species is named after its occurrence in the Gia Lai Province, where the type locality is located (adjective in nominative singular case).

Figures

FIGURE 5. A–D: Tetraserica gialaiensis Pham & Ahrens, new species (holotype). A: aedeagus, left side lateral view; B: parameres, dorsal view; C: aedeagus, right side lateral view; D: habitus. Scale: 0.5 mm. Habitus not to scale.