Gastroserica (Helioserica) kachin Ahrens & Pham, 2023

Ahrens, Dirk & Pham, Phu, 2023, Updates on the taxonomy and distribution of Gastroserica Brenske, 1897, Microserica Brenske, 1894, and Moronoserica Ahrens, Lukic & Liu, 2023 (Coleoptera: Scarabaeidae: Sericinae: Sericini), Zootaxa 5346 (5), pp. 551-566 : 552-553

Gastroserica (Helioserica) kachin Ahrens & Pham , new species

Figs. 1A–D

Type material examined. Holotype ♂ “ Myanmar (Burma) Provinz Kachin state Mt. Emaw Bum nach Kanphant 20.V.2006 leg. Michael Langer, Stefan Naumann & Swen Löffler, coll. M. Langer / Waldcamp – Holzmeiler H = 2358 m N 26°09’232’’ E 098°31’164’’ / Sericini spec. Det. D. Keith 2008 / 1216 Sericini Asia spec.” ( ZFMK).

Description of holotype. Length: 5.2 mm, length of elytra: 3.8 mm, width: 3.5 mm. Body oval, body dark blackish, dorsal surface shiny, with some blue-iridescent shine, legs and antennal club black to dark brown, antennal funiculus yellow, dorsal surface nearly glabrous.

Labroclypeus narrow and almost semicircular, as wide as long, widest at base, lateral margins moderately convex and convergent to strongly rounded anterior angles; anterior margin weakly concave medially, margins weakly reflexed; lateral margins and ocular canthus produce a blunt angle; surface medially weakly convexly elevated, finely densely punctate, with numerous long, erect setae; frontoclypeal suture finely incised and curved medially. Frons shiny, with dense, fine punctures, beside eyes and behind frontoclypeal suture with a few single short setae, otherwise with minute setae in punctures. Smooth area in front of eyes as wide as long. Ocular canthus sparsely finely punctate, narrow and moderately long (1/3 of ocular width), with a terminal seta. Eyes moderately large, ratio of diameter/interocular width: 0.57. Antenna with ten antennomeres; club composed of four antennomeres, weakly reflexed, twice as long as remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately wide, widest at base, lateral margins in basal half almost straight and convergent anteriorly, anteriorly weakly evenly convex and convergent to blunt and moderately produced anterior angles, posterior angles blunt and moderately rounded. Anterior margin of pronotum convex, with robust and complete marginal line; basal marginal line absent; surface finely and moderately densely punctate, with minute setae in punctures, anterior and lateral anterior margins sparsely setose. Hypomeron carinate, weakly produced ventrally. Scutellum triangular, finely and sparsely punctate, on median base less densely punctate.

Elytra moderately short, widest at middle, striae finely impressed, finely and densely punctate, intervals weakly convex, with fine and sparse punctures concentrated along striae, with very minute setae in punctures, odd intervals with a few short setae; epipleural edge robust, ending at slightly rounded external apical angle of elytra, epipleura densely setose, apical border chitinous, without a fringe of short microtrichomes (visible at ca 100x magnification).

Ventral surface shiny, finely and densely punctate, metasternum sparsely covered with fine, short, or very minute setae; metacoxa glabrous, with a few single setae laterally. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.54. Abdominal sternites finely punctate, with a transverse row of coarse punctures, each bearing a robust seta. Pygidium with dull surface, strongly convex, with mixed finer and dense, larger, partly longitudinally rugose punctures, without smooth midline, with numerous short setae and a few longer in the larger punctures.

Legs moderately wide; femora finely and sparsely punctate, with two longitudinal rows of longer setae. Metafemur moderately shiny, anterior margin acute, without submarginal serrated line; anterior row of seta-bearing punctures present; ventral posterior margin finely serrate at apex, only weakly widened in apical half, dorsal posterior margin serrate, with a few short setae basally. Metatibia moderately long and wide, widest at middle, ratio width/ length:1/3.5; dorsal margin sharply carinate, with two groups of spines, basal group at middle, apical one at three quarter of metatibial length, in basal third with a few robust single setae; lateral face longitudinally convex, finely and sparsely punctate, along midline smooth, with minute setae in punctures; ventral edge finely serrate, with three robust equidistant setae; medial face smooth, apex interiorly near tarsal articulation sharply truncate. Tarsomeres with fine, sparse setae ventrally, neither laterally nor dorsally carinate, dorsally impunctate; metatarsomeres glabrous, with a strongly serrated ridge ventrally and a parallel subventral smooth carina immediately beside it; first metatarsomere little shorter than following two tarsomeres combined and little less than twice as long as dorsal tibial spur. Protibia short, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Aedeagus: Figs. 1A–C . Habitus: Fig. 1D . Female unknown.

Diagnosis. Gastroserica (H.) kachin , new species, is in external appearance very similar to G. (H.) piceocoerulea Ahrens, Lukic & Liu, 2023 , but in shape of aedeagus it differs from the latter by the shorter, more mesally directed basal lobe of left paramere; the right paramere is in contrast to most species of this group not widened at apex (lateral view).

Etymology. The new species is named after its occurrence in the Kachin Province (noun in apposition).

Distribution. So far known only from the type locality (Mt. Emaw Bum to Kanphant) in Myanmar.

Figures

FIGURE 1. A–D: Gastroserica (Helioserica) kachin Ahrens & Pham, new species (holotype); E–I: G. (H.) horii Ahrens & Pham, new species (holotype). J–M: G. (Gastroserica) muongphangensis Ahrens & Pham, new species (holotype). A, E, J: Aedeagus, left side lateral view; C, H, L: Aedeagus, right side lateral view; G: Aedeagus, dorsal view; B, F, K: Parameres, dorsal view; D, I, M: Habitus (not to scale). Scale: 0.5 mm.