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 waldenfelsi Dechambre 1981: 267 (new combination) Diagnosis Tetragus waldenfelsi differs from P. impunctatus in the following characters: pronotal surface punctate (punctures large on concavity, fine on other surfaces) in male; surface of tergite VIII flattened to slightly convex in lateral view in female. Type material Strategus waldenfelsi , holotype not examined. Gibboryctes porioni , holotype male, labelled: (a) ‘trouve cadavre/1e 2 Dmars 1977/a SAÜL/ Guyane Francaise / Coll . Th. PORION’ [old label, partially handwritten]; (b) ‘HOLOTYPE’ [red label]; (c) ‘gibboryctes/porioni n.sp. mihi/ HOLOTYPE /R. -P. Dechambre det. 1980’ [old white label, partially handwritten]; (d) ‘photographie 1978/R. -P. Dechambre’ [old white label, partially handwritten]; (e) ‘gibboryctes/ waldenfelsi (Endrödi) /R. -P. Dechambre det. 1985’ [old white label, bordered in black border, partially handwritten]; (f) ‘MNHN/EC8408’ [white label/ bordered in black] ( MNHN ). Non-type material PANAMA : Darién , June–July 1979 , R . Hinds – 1 male ( BCRC ) . FRENCH GUIANA : Petit Savi PK, 10 January 2008 , Y . Ponchel – 1 male , 1 female ( EPGC ); RN1 PK70 , February 2009 , Y . Ponchel – 1 male , 1 female ( CERPE ) . BRAZIL : Amazonas , Maua , 10 June 1965 – 1 male ( BCRC ); Reserva Ducke , 26 km NE Manaus , 28 February 1977 , B .C. Ratcliffe – 1 female ( BCRC ) . Mato Grosso , Xingu , October 1954 , M . Alvarenga leg . - 1 female ( CERPE ) . Male ( Figure 5 (a,b)) Redescription. Length : 22.6–27.9 mm . Width : 10.8–12.4 mm . Colour : Dorsal surface dark reddish; legs and ventral surface dark reddish brown. Head : Clypeus triangular, short (3.2 times wider than long), acuminate anteriorly, glabrous, finely punctate. Frontoclypeal suture well marked, provided with a short, conical tubercle at middle. Frons glabrous; sides with large, deep, C-shaped, coalescent punctures; longitudinal middle area from smooth to finely punctate; transversal posterior area smooth. Interocular width equals 3.5 times transverse eye diameter. Ocular canthus subrectangular, glabrous, rugopunctate. Mouthparts : Labrum parabolic, covered with a fringe of bristles at apex ( Figure 6 (e)). Mandibles with 2 teeth (1 apical, 1 subapical) at outer margin separated by a narrow notch; apical tooth truncated apically; subapical tooth rounded ( Figure 7 (e)). Maxillae wider at middle than basis; outer margin rounded; inner margin with 6 teeth (3 apical, 2 medial, 1 basal); apical and medial teeth scythe-shaped; basal tooth triangular, smaller than previous ones ( Figure 8 (e)). Labium with rounded sides at basal half, convergent on apical half; apex wide, slightly rounded; surface surrounded with dense, setigerous punctures. Antennae : Club oval, subequal in length to antenomeres II–VII combined. Thorax : Pronotum with complete border; anterior margin with a horn at middle, followed by a wide, deep, U-shaped concavity, nearly reaching the posterior margin; horn, in dorsal view, from short (not covered the head) to long (covered the head), wide at basis, narrow laterally at middle, bifurcate at apex; horn, in lateral view, rarely wide dorsoventrally, obliquely produced regarding anteroposterior body axis; pronotal sides strongly convex in lateral view; surface of concavity with large, ocellate, irregularly scattered punctures ( Figure 9 (d)); sides usually smooth, posterior area finely punctate. Scutellar plate subtriangular, glabrous, irregularly punctate anteriorly, posteriorly smooth. Elytral with 10 well-marked striae (1 sutural, 5 discal, 4 lateral); punctures on striae ocellate, large, deep anteriorly, becoming shallow, small towards posterior area; first interstria covered with large, ocellate, oval punctures; other interstriae finely punctate. Legs : Protarsomere V clavate, elongated, subequal to tarsomeres II–IV combined; tarsomeres I–IV subequal in length, beaker-shaped. Protibiae with IV triangular, acute, short teeth, produced on outer margins. Mesofemora oval, scarcely setose ventrally. Mesotibiae cylindrical, with 2 carinae on outer surface (1 basal, 1 medial); carinae and apex covered with stout spinules like setae. Metafemora with ventral surface glabrous, from smooth to finely punctate at discal area. Metatibiae similar to mesotibiae. Meso- and metatarsi with tarsomeres I–IV gradually decreasing in size; outer apex of tarsomere I produced, acute, with 3 stout spinules; tarsomere V subequal in length to tarsomeres II–IV combined. Abdomen : Tergite VII rugopunctate, with no stridulatory apparatus. Tergite VIII transverse strongly convex in lateral view; surface densely setose, rugopunctate on sides, finely punctate on disc. Ventrites II–V subequal in length, rugopunctate on sides, finely punctate on disc, with an incomplete row of setigerous punctures confined on sides; ventrite VI weakly rugopunctate on sides, finely punctate on disc, posterior margin setose, widely emarginate at middle. Venter : Prosternal process conic, densely setose. Mesoventrite completely setose. Metaventrite nearly completely setose; discal area glabrous. Aedeagus : Parameres, in dorsal view, wide at basal half, narrow at middle, becoming gradually wide at apical half, scarcely bristled lateroventrally at inner side of apex ( Figure 10 (g)). Parameres, in lateral view, sinuous dorsoventrally, ventrally with a strong carina at basis, apex narrow ( Figure 10 (h)). Female ( Figure 5 (c,d)) Redescription. Length : 26.8–32.3 mm ; Width : 11.9–14.1 mm . Distinct from male in the following characters: Head : Clypeus from subtrapezoidal to subtriangular, truncated or slightly rounded at anterior margin, coarsely rugopunctate ( Figure 11 (e)); frons entirely, coarsely rugopunctate. Thorax : Pronotum with 2 flattened, transverse tubercles contiguous to middle of anterior margin; pronotal concavity V-shaped, transversely rugopunctate; concavity V-shaped, coarsely rugopunctate ( Figure 11 (e)); sides of pronotum weakly convex in lateral view. Legs : Metafemora with large, oval punctures on ventral surface. Abdomen : Tergite VIII flattened to weakly convex in lateral view; ventrite V parabolic, moderately punctate, with no posterior emargination ( Figure 13 (d)). Geographic distribution ( Figure 14 (a)) Panama , French Guiana , Brazil (Amazonas; Mato Grosso , new state record). Remarks Males of T. waldenfelsi comb. nov. have allometric development evidenced by the shape of male horn sometimes broader dorsoventrally at middle wider than basis in lateral view; longer (covering the head in dorsal view, surpassing the anterior margin of clypeus in lateral view) or shorter (not covering the head in dorsal view).