Neoserica samuelsoni Ahrens, 2022

Ahrens, Dirk, 2022, New Gynaecoserica Brenske, 1897 species and further new bicolored species of the Neoserica calva group (Coleoptera: Scarabaeidae: Melolonthinae: Sericini), Zootaxa 5165 (2), pp. 180-190 : 187-188

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Neoserica samuelsoni Ahrens

new species

Neoserica samuelsoni Ahrens , new species

Fig. 2I–L View FIGURE 2

Type material examined. Holotype: ♂ “ Laos: Vientiane Prov. Ban Van Eue 800m, 11.IV.1965 / Native collector Bishop Museum ” ( BPBM).

Description of the holotype. Body length: 4.6 mm, length of elytra: 3.2 mm, width: 3.0 mm. Body short-oval, brown, dull tomentum of pronotum somewhat grey, antennal club and legs yellow, pronotum as well as a large spot on the disc of elytra reddish brown, dorsal surface dull and nearly glabrous, labroclypeus and anterior third of frons shiny.

Labroclypeus semi-circular, distinctly wider than long; lateral margins convex and strongly convergent anteriorly; anterior angles almost blunt but moderately rounded at tip; anterior margin shallowly emarginate medially; margins moderately reflexed; surface flat and shiny, finely and densely punctate, with numerous erect setae. Frontoclypeal suture indistinct, strongly curved. Smooth area anterior to eye convex, as wide as long. Ocular canthus moderately long and wide (equal to 1/3 of ocular diameter), finely and densely punctate, with a single terminal seta. Frons on anterior half shiny, finely and densely punctate, with a few long setae beside eyes and behind frontoclypeal suture, otherwise glabrous; on posterior half dull, finely and densely punctate, glabrous. Eyes small, ratio diameter/interocular width: 0.47. Antenna with ten antennomeres, club with five antennomeres, slightly reflexed, and 1.3 times as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly. Labrum transverse, short, not produced medially, with weak median sinuation.

Pronotum transverse, widest at middle; lateral margins moderately evenly convex and weakly convergent anteriorly and posteriorly; anterior angles produced and moderately sharp; posterior angles blunt; anterior margin with a fine complete marginal line, straight; surface densely and coarsely punctate, with minute setae in punctures; lateral and anterior border sparsely setose, on anterolateral disc with a few long erect setae; basal margin without marginal line; hypomeron distinctly carinate basally. Scutellum long, with fine, dense punctures, and minute setae in punctures.

Elytra short-oval, widest at posterior third; striae weakly impressed, finely and moderately densely punctate; intervals weakly convex, with sparse, fine punctures mainly concentrated along striae, with minute setae in punctures, and a few short adpressed setae on odd intervals. 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: 1/1.74. Pygidium moderately convex and dull, finely and densely punctate, without smooth midline, with short 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 ventral margin in apical half not serrated and moderately widened at apex; posterior dorsal margin finely serrated, glabrous. Metatibia slender and short, widest at apex, ratio of width/length: 1/3.3; dorsal margin sharply carinate, with two groups of spines; basal group at first third, apical group at two thirds of metatibial length; basally with a single fine seta but without serrated longitudinal margin; lateral 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 concavely moderately deeply truncate interiorly near tarsal articulation. Tarsomeres ventrally with sparse, short setae, not carinate laterally, impunctate dorsally; metatarsomere 1 little longer than dorsal metatibial spur and as long as following two tarsomeres combined. Protibia short, bidentate, not widened laterally before basal tooth; anterior claws symmetrical, basal tooth of inner claw sharply truncate at apex.

Aedeagus: Fig. 2I–K View FIGURE 2 . Habitus: Fig. 2L View FIGURE 2 . Female unknown.

Diagnosis. Neoserica samuelsoni Ahrens , new species is in shape of parameres rather similar to N. fragilis Ahrens & Pham, 2021 . Neoserica samuelsoni Ahrens , new species differs by the bicoloured elytra, and by the shape of the parameres: The left parameres does not have a lateral apical tooth and its basal lobe is less distinctly separated from the distal portion as in N. fragilis ; the right paramere is distinctly shorter than the left (in N. fragilis it is the opposite).

Etymology. The new species is named after the former curator G.A. Samuelson of the beetle collection at the Bishop Museum (BPBM).