Tetraserica phamanhi 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 : 468-470

Tetraserica phamanhi Pham & Ahrens , new species

Fig. 7A–D

Type material examined. Holotype: ♂ “[ Vietnam] Son La Pro., Thuan Chau Dis., Copia NR.; 27–28.iv.2016; UV light trap; H.V. Tru leg.” ( IEBR) . Paratypes: 1 ♂ “[ Vietnam] Son La Pro., Thuan Chau Dis., Copia NR.; 1.v. 2016; UV light trap; H.V. Tru leg.” ( IEBR) , 1 ♂ “[ Vietnam] Son La Pro., Thuan Chau Dis., Copia NR.; 18.iv–2.v.2016; Malaise trap; H. V. Tru leg.” ( IEBR) , 2 ♂♂ “[ Vietnam] Son La Pro., Thuan Chau Dis., Copia NR.; 14.v.2017; P.V. Pham leg., UV light trap ” ( IEBR, ZFMK) .

Description of the holotype. Length: 8.1 mm, length of elytra: 6.7 mm, width: 5.1 mm. Body oval, dark reddish brown, labroclypeus and dorsal surface shiny, glabrous.

Labroclypeus subtrapezoidal, wider than long, widest at base, lateral margins moderately convex, anterior angles very strongly obtuse; anterior margin emarginate medially; lateral margin and ocular canthus producing a distinct blunt angle, margins moderately reflexed; surface medially convex, shiny, moderately and densely punctate, without setae; frontoclypeal suture moderately impressed and moderately bent medially; smooth area in front of eye approximately 3 times as wide as long; ocular canthus moderate and triangular(1/3 of ocular diameter), weakly punctate, with one terminal seta. Frons weakly shiny and smooth, with only a few erect setae beside eyes. Eyes small, ratio of diameter/ interocular width: 0.57.

Antenna yellowish brown, with ten antennomeres, club in male with four antennomeres, little longer than 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 slightly convex medially, with a fine, complete marginal line. Surface densely and finely punctate, with minute setae in punctures; lateral and anterior 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, with some erect, short setae, punctures with minute setae; epipleural edge robust, ending at convex external apical angle of elytra, epipleura sparsely setose, apical border membraneous, with a rim of short microtrichomes.

Ventral surface dull, reddish brown, with large 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 as wide as mesofemur. Ratio of length of metepisternum/ metacoxa: 1/1.6. Pygidium moderately convex and dull, coarsely densely punctate, without smooth midline, punctures with fine setae along apical margin.

Legs moderately wide; femora with two longitudinal rows of setae, finely and moderately densely punctate; metafemur wide, moderately shiny, its anterior margin acute, lacking an adjacent serrated line; ventral posterior margin straight, smooth and moderately widened in apical half; dorsal posterior margin smooth, without short setae basally. Metatibia short, widest at middle; ratio width/ length: 1/ 2.9; dorsal margin weakly longitudinally convex, with two groups of spines, basal one at first third, apical one at two thirds of metatibial length, basally with a few short single setae; lateral face weakly finely punctate; ventral margin finely serrate, with four robust equidistant setae; medial face smooth; apex interiorly near tarsal articulation moderately concave. Tarsomeres in distal half with fine, dense setae ventrally, dorsally smooth; metatarsomeres with a strong serrated ridge and glabrous ventrally, first metatarsomere as long as following two tarsomeres combined, distinctly longer than dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus. Fig. 7A–C . Habitus: Fig. 7D . Female unknown.

Diagnosis. Tetraserica phamanhi Pham & Ahrens , new species is in the shape of aedeagus very similar to that of T. mengeana Liu, Fabrizi, Bai, Yang & Ahrens, 2014 and T. allomengeana Fabrizi, Dalstein & Ahrens, 2019 ; the new species differs by the presence of a convex basal lobe at the base of the right paramere which is subequal in length the apical portion (distal to paramere’s bent); in the latter two species this basal portion is only slightly elevated and half as high as the distal portion of the paramere; additionally, in the new species the left paramere also lacks the blunt tooth on dorsal margin.

Variation. Length of body: 8.6–9.0 mm; length of elytra: 6.7–6.8 mm; maximum width: 5.2–5.4 mm.

Etymology. This species is named after Associate Professor Pham Van Anh (Department of Environment, University of Science, VNU Hanoi) who has arranged the expeditions in 2016 and 2017 which collected the type material of this species (noun in genitive case singular).

Figures

FIGURE 7. A–D: Tetraserica phamanhi Pham & Ahrens, new species (holotype); E–H: T. semikontumensis Pham & Ahrens, new species (holotype). A, E: aedeagus, left side lateral view; B, F: parameres, dorsal view; C, G: aedeagus, right side lateral view; D, H: habitus. Scale: 0.5 mm. Habitus not to scale.