Gibboryctes ebeninus Duarte and Grossi, sp. nov.

(Figures 2; 6 (b); 7(b); 8(b); 11(b); 12(c,d); 13(b); 14(b))

Diagnosis

Gibboryctes ebeninus differs from other Gibboryctes species by the following combination of characters: Body colouration black (Figure 2); labrum subtrapezoidal, bearing truncated apical margin (Figure 6 (b)); maxillary palpomere II long, about 2.8 times longer than wide at middle (Figure 8 (b)); head with punctate frons (Figure 11 (b)); pronotal anterior corners weakly punctate (punctures predominantly spaced above 1 diameter of punctures) (Figure 12 (c)); juxtasutural interstriae with scarce and large punctures, confined on anterior area of elytra (Figure 12 (d)).

Type material

Holotype female dissected, labelled: (a) ‘ Brasil, Minas Gerais / Três Marias, xi-1991,/F. Z. Vazde-Mello’ [white label]; (b) ‘ Gibboryctes ebeninus sp. nov. / HOLOTYPE / Duarte & Grossi Det. 2021’ [red label] (CERPE). One female paratype with same data as holotype (CERPE). One female with same data as holotype, except: (a) ‘ x-1989 ’ [white label] (CERPE). Paratypes with a yellow paratype label .

Holotype description

Female (Figure 2). Length: 26.54 mm. Width: 12.57 mm. Colour: Completely black. Head: Clypeus triangular, transverse (3 times wider than long), slightly constricted laterally, rounded apically; surface densely rugopunctate, with scattered setae on sides separated by a glabrous middle area. Frontoclypeal suture with transverse, short, flattened, weakly bilobed tubercle. Frons slightly concave, scarcely, irregularly punctate; interocular width equals 4.0 transverse eye diameters. Ocular canthus subrectangular, transverse, glabrous. Mouthparts: Labrum trapezoidal, truncated at apical margin (Figure 6 (b)). Mandibles bidentate; teeth lobed, exposed laterally to clypeus; basal tooth larger in size compared to apical tooth (Figure 7 (b)). Maxillary galea rounded at apex; inner margin with 3 small, pointed teeth located at middle of galea; stipe weakly produced laterally (shorter in length than maxillary palpomere I) (Figure 8 (b)). Maxillary palpomere II beaker-shaped, elongate (2.8 times longer than width at middle) (Figure 8 (b)). Labium suboval, with subapical sides constricted, apex rounded; surface surrounded with large, deep, coalescent, bristled punctures; disc scarcely punctate. Thorax: Pronotum rounded laterally in dorsal view, weakly convex in lateral view; anterior tubercle obsolete; posterior border interrupted at middle; anterior area densely covered with large, deep, C-shaped punctures; punctures gradually becoming small, shallow towards posterior area; anterior corners scarcely punctate (punctures predominantly spaced about 1 diameter of punctures (Figures 11 (c) and 12 (c)). Scutellar plate parabolic in shape, glabrous, scarcely punctate; punctures confined to anterior area, scattered about 1 diameter of punctures. Elytra longitudinally covered with 9 well-marked striae (1 sutural, 4 discal, 4 lateral); each stria with a row of large, ocellate, deep punctures; anterior area of first interstria with 9 large, deep, ocellated punctures; other interstriae finely punctate (Figure 12 (d)). Legs: Mesotibial outer carinae with 15 stout spinules like setae (6 on basal carina, 9 on medial carina). Metatibial outer carinae with short, stout spinules. Abdomen: Tergite VIII rugopuctate on sides, punctate on disc. Ventrites II–V densely rugopunctate on sides, finely punctate on disc; ventrites II–V with a row of setigerous punctures confined to sides; ventrite VI parabolic in shape, surrounded with rugopunctures, smooth on discal area, covered with short setae on posterior margin (Figure 13 (b)).

Variation

Paratypes do not vary significantly from the holotype.

Male

Unknown.

Etymology

From latin ‘ ebeninus ’, meaning ‘ebony’, in reference to the black and shiny surface of the body.

Geographic distribution (Figure 14 (b))

Brazil (Minas Gerais).

Remarks

Gibboryctes ebeninus sp. nov. is the most distinct species in the genus by virtue of four exclusive characters: body with dark colour; maxilla with short lateral stipe (shorter compared to maxillary palpomere I; maxillary palpomere II elongate (2.8 times longer than wide at middle); elytral interstriae predominantly covered with fine punctures, large punctures being scarce. These characters in the other two species are: body colouration reddish brown or dark reddish brown; frons coarsely rugopunctate; maxilla with stipe produced laterally (longer compared to maxillary palpomere I); maxillary palpomere II shorter (1.6 times longer than wide at middle); elytral interstriae almost entirely covered with large punctures.