Taxonomic revision and notes on natural history of the enigmatic beetle genus Gibboryctes Endrödi (Coleoptera: Melolonthidae: Dynastinae) Author Costa, Leidiane O. Author Duarte, Paulo R. M. Author Iannuzzi, Luciana Author Grossi, Paschoal C. text Journal of Natural History 2022 2022-05-17 56 1 - 4 191 225 http://dx.doi.org/10.1080/00222933.2021.2017499 journal article 82886 10.1080/00222933.2021.2017499 5cd01cfe-52bb-4092-97b2-804c3c7d145d 1464-5262 6758313 D766FC5E-CEC8-4184-BE90-C25350B90612 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.