Hexarhopalus (Leprocaulus) arunachalpradeshensis, Purchart, 2025

Hexarhopalus (Leprocaulus) arunachalpradeshensis sp. nov.

( Figs 3a–k View FIGURE 3 )

Type material. Holotype, sex not examined ( BMNH): {white, printed} NE INDIA; ARUNACHAL PR. / betw. Dirang & Bomdila Pass / 27°19´N 92°22´E; 2200m / L. Dembický leg.; 15.vi2004 GoogleMaps . Paratypes. (2 ♂ BMNH, 1 ♂ LPCB) : same data as holotype; (1 BMNH): NE INDIA; ARUNACHAL PR. / W of BOMBDILA; 2600m; / 27°16´N 92°24´E; / L. Dembický leg.; 17.v.2004 GoogleMaps .

Condition of holotype: Last two protarsomeres on right front leg missing.

Differential diagnosis. In general appearance, due to its rugose or roughly punctured pronotal disc and convex to carinate elytral interstriae with rather large tubercles, the new species resembles H. eva Bečvář & Purchart, 2008 ( Thailand), H. jendeki Bečvář & Purchart, 2008 ( India), H. difformis ( Pic, 1922) ( Laos, Thailand, Vietnam, China), H. xui Ren & Xu, 2011 ( China, Yunnan), H. sinjaevi Bečvář & Purchart, 2008 ( Vietnam), H. qiului Jiang, Bai, Ren & Wang, 2020 ( China, Yunann) and H. xuhaoi Jiang, Bai, Ren & Wang, 2020 ( China, Xizang). Compared with H. eva and H. jendeki , the new species can be reliably distinguished mainly by smooth prothoracic hypomeron, which is densely and coarsely wrinkled in the two latter species, and by the different surface of the pronotal disc, which is densely and coarsely rugose in H. eva ( Figs 6b, j View FIGURE 6 ) and H. jendeki , whereas it is densely and roughly punctured in H. arunachalpradeshensis sp. nov. Compared with H. difformis , H. sinjaevi and H. xui , it differs mainly in the absence of midlongitudinal depression ( H. difformis , see Fig. 17 in Jiang et al. (2020)) or groove ( H. sinjaevi — Figs 6g, o, H View FIGURE 6 . xui, see Fig. 22 in Ren & Xu 2011). Hexarhopalus qiului (see Figs 12, 13 in Jiang et al. (2020)) can be distinguished from the new species mainly by its roughly and irregularly wrinkled pronotal surface covered by short hairs (roughly punctured and glabrous in the new species), by head covered by short hairs (completely glabrous in the new species) and large shiny tubercles in elytral interstriae, especially in the first and third inner interstriae (tubercles are much smaller in the new species). From H. xuhaoi (see Fig 15 in Jiang et al. 2020) it differs mainly by completely glabrous head and pronotal surface and a roughly punctured surface of the pronotum (head and pronotum covered by short hairs, pronotum sparsely and finely punctured in H. xuhaoi ).

Description. Size of holotype 9.4 × 3.5 mm. Brown, dull-shiny, with antennae and mouthparts at least partly reddish brown. Body elongate subcylindrical, glabrous ( Figs 3a–b View FIGURE 3 ).

Head dark brown, glabrous, shagreened and therefore dull, shallowly but densely punctured, punctures´ diameter same as diameter of eye facet, narrower than pronotum in ratio 1:1.22 ( Figs 3a, c View FIGURE 3 ). Frontoclypeal suture well developed, moderately deep, reaching clypeal margin. Ocular sulcus moderately deep, distance between eyes 2.32× wider than their transverse diameter (DV). Antenna pale brown, pubescent, 1.5× longer than pronotum.

Pronotum dark brown, shagreened, dull, subquadrate, broadest at middle, PW:PL ratio is 1: 1.15 ( Figs 3a, c View FIGURE 3 ). Entire surface of pronotum irregularly and coarsely punctate, with punctures´ diameter slightly larger than eye facet. Oblique indentation in posterior angles relatively long, deep and smooth ( Fig. 3d View FIGURE 3 ). Anterior margin of pronotum straight, not rimmed. Base of pronotum completely rimmed. Prothoracic hypomeron smooth, shagreened, dull, impunctate, separated from pronotal disc by lateral groove.

Elytra brown, shagreened, 1.86× longer than its width, 3.25× longer and 1.52× wider than pronotum, dorsally flattened (LV), very slightly dilated posteriad, broadest at posterior third ( Fig. 3a View FIGURE 3 ). Declivity of elytra before apex moderate (LV). Elytral humeri well developed. Elytral striae formed of dense row of separated deep and large rounded to longitudinal punctures. First two inner elytral interstriae flat to convex with irregularly situated granules of the same size as punctures in elytral striae. Remaining interstriae convex to slightly carinate (especially in anterior part of elytra) with more or less regularly situated shiny granules on their top. Base of elytra rimmed with moderately raised carina. Winged. Scutellum triangular ( Fig. 3c View FIGURE 3 ).

Prosternum brown, shagreened, glabrous, dull. Prosternal process with distinct and rather deep midlongitudinal groove between procoxae, apically broadly rounded, as wide as procoxa. Mesosternum pale brown, shagreened, dull, wrinkled, glabrous; in middle with shiny midlongitudinal carina. Metasternum pale brown, shagreened, dull, very finely and shallowly but densely punctate, finely pubescent. Approximately 2.5× longer than mesocoxa. Abdominal ventrites pale brown, shagreened, dull, very finely and shallowly but densely punctate, finely pubescent, abdominal ventrite I–III rimmed laterally ( Fig. 3b View FIGURE 3 ).

Legs. Brown, simply, finely and densely punctate. Femora claviform, glabrous. Tibiae straight, finely pubescent. Tarsi dorsally pubescent.

Aedeagus, spiculum gastrale, male inner sternite VIII, male inner tergite VII and VIII are shown in Figs 3e–k View FIGURE 3 .

Variability of size: 8.6–10.0 × 3.0– 3.5 mm.

Etymology. The specific epithet refers to the area of the species occurrence, Arunachal Pradesh; the name is treated as an adjective.