Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785),

Prandi, Massimo, Grossi, Paschoal C. & Vaz-De-Mello, Fernando Z., 2020, Revision of the Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785) species group (Coleoptera, Scarabaeidae, Dynastinae), ZooKeys 999, pp. 109-145: 109

publication ID

publication LSID

persistent identifier

treatment provided by

ZooKeys by Pensoft

scientific name

Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785)


Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785)  Figures 8A-EView Figure 8, 13A-CView Figure 13

Scarabaeus gyas  Jablonsky, 1785: 263-267

Scarabaeus  Goliath  Voets, 1766 (unavailable name).

Scarabaeus esau  Jablonsky, 1785; synonym by Burmeister 1847: 277-278.

Scarabaeus laniger  Olivier, 1789; synonym by Burmeister 1846: 106-108.

Megasoma gyas rumbucheri  Fischer, 1968, syn. nov.

Type material.

The holotype is the specimen seen and illustrated by Voets, whose illustration was later copied by Jablonsky (1785: Plate 4 fig. 4) and is probably lost.


Megasoma gyas  occurs in the Caatinga biome of the Brazilian states of Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, and Sergipe (Fig. 9View Figures 9, 10). The distribution range of this species overlaps a portion of the "subregioes nordestinas" ( Vasconcellos et al. 2010; Beserra Nobre et al. 2014) of “Meio-norte” and “Sertao” regions (Fig. 10View Figures 9, 10). The Caatinga biome (xeric shrubland and thorn forest) occupies an area of 497,000 sq. miles, i.e., 10% of Brazilian territory (Fig. 9View Figures 9, 10); it is a recent biome located on an ancient seabed. This biome experiences long periods of drought, which can last up to eight months. It is mainly composed of dry Savannah ( Coutinho 2016).

Material examined.

13 major ♂, 4 minor ♂, and 7 ♀ from the following Brazilian states: Alagoas, Canapi, X 2018, J. Dantas Leg. (1 ♂, CERPE, 1 ♀, MPC); Pernambuco, Timbaúba, with indication of 1 hour and half by car inland of Recife, XII 1979 (1 ♂ and 1 ♀, MPC); Areia, VI 1945 (1 ♂, MPC); Araripina, 1953 (2 ♂, LMC); Brazil, Estaçao … (not visible), G.L.Sladen Leg., 1925 (2 ♂, 1 ♀, BMNH); Custódia, X 2012, leg. C.E.B Nobre (1 ♂, MPC); São José do Egito (sitio Humaitá), IV 2010 Leg. R.M. Correia (1 ♂, CEMT); Igarassu, Três Ladeiras, Usina São José XII 2017, (1 ♀, CERPE); Sergipe, didactic collection of the University, no further data (1 ♂, CERPE, 1 ♂, MPC); Capela, Ref. Vida Silv. - Mata do Jumco Station (RUSMJ), III 2014 Leg. O.G. Moura (1 ♂, CERPE); Ceará, no data (1 ♂, CERPE); Ceará, no data (1 ♂, 1 ♀, EPGC); Piauí, didactic collection of the University, Teresina, São Francisco, IV 2001 (1 ♂, CERPE); Rio Grande do Norte, Tenente Laurentino Cruz, I 2015, leg. R. Andreazze (1 ♂, CERPE, 1 ♀, MPC); Paraiba, Patos, no further data, (1 ♂, CERPE, 1 ♀, MPC).

Male (Fig. 8View Figure 8). Size. L: 77 mm; TL: 88 mm; PL: 21 mm; PW: 35 mm; EL: 49 mm; EW: 42 mm; CL: 23 mm; PH: 8.5 mm. General appearance. Uniformly dark brown, covered by yellowish short, fine, dense pubescence; head, including horn, consistently black with yellowish sparse bristles at base. Head. Cephalic horn: short, projecting forwards and curved upwards. In lateral view flat, distally bent upwards. In dorsal view, narrower at base gradually broadened towards distinctly forked apex. Apex U-shaped, with slightly divergent, long, tips (Fig. 8CView Figure 8). Distance between tips 11.5 mm. Sides bordered with a weak, hardly detectable rim, from base to mid-length. Dorsal side at base with relief of an almost imperceptible tooth. Pronotum. Whole surface covered by fine, dense yellowish pubescence. Anterior angles projecting as small but elongate, sharp, parallel horns, slightly bent outwards; width of horn at base 4.5 mm; length from base to tip 8.5 mm; distance between apices of anterior horns 23 mm. Median thoracic horn longer than lateral ones, length 15 mm, with characteristic sickle-shaped form, dorsal side with glossy black line, ventral side of median horn with recumbent fine pubescence. PL/TH ratio 2.470. L/PL ratio 3.666, showing a fairly elongated feature of the body. Elytra. Surface covered by fine, dense, recumbent, yellowish pubescence apart from elytral suture and epipleura, glabrous; EL/EW ratio 1.166. Elytral surface covered by (two or three on each elytron) visible longitudinal ridges: sutural edge black, glabrous, punctate; other pubescent ridges spaced out. Elytra in lateral view more convex proximally and then gradually flattened towards apex. L/EL ratio 1.571, elongate.

Abdomen. Sides covered with short, very fine, yellowish brown pubescence, medially almost glabrous. Legs. Fore tibia almost straight, inner apical edge strongly dilated inwards, 23 mm in length. Anterior edge of protibia V-shaped. Lateral edge with three strong teeth, decreasing in size proximally, from base to apex; basal tooth more distant from subapical tooth than the latter from the apical tooth. Basal and subapical teeth large, triangular, thick, sharp, pointing rearwards; apical tooth short, pointing forwards. Inner apical spur strongly curved downwards, as long as apical tooth. Fore tarsi length 25 mm. Aedeagus. Parameres of tegmen elongate and narrow, as in Fig. 31A, BView Figure 31. Thickness of section from anterior phallobase to median lobe also narrow.

Variation, males.

Major and medium males always with apex of cephalic horn U-shaped, with long tips. Minor males with cephalic horn length not more than twice head length, from vertex to clypeus, bear the apex of cephalic horn V-shaped with shorter tips and wider body. Dorsal tooth of cephalic horn absent in medium and minor males.


L: 53-77 mm; TL: 59-88 mm; PL: 14-21 mm; PW: 24-35 mm; EL: 38-49 mm; EW: 30-43 mm; CL: 10-23 mm; FL: 15-23 mm; TF: 17-25 mm.

Female (Fig. 13View Figure 13). Size. L: 54 mm; PL: 16 mm; PW: 23 mm; EL: 34 mm; EW: 30 mm. General appearance. Uniformly black; elytra with 6/7 of its surface covered by grey-brownish dense pilosity. Head. Fronto-clypeal suture with a double conical tubercle. Pronotum. Surface dull, coarsely punctate-rugose, strongly convex; posterior median carina 8 mm long, ½ of total PL. Anterior angles obtusely projecting, yet with sharp tips. Lateral edges with the presence of sparse bristles. Elytra. Surface with puncture mixed to wrinkles anteriorly, glossy black; punctate black surface extending for 8 mm. Elytral pubescence thick, uniform, with clearly visible longitudinal ridges, three or four for each elytron, almost equidistantly spaced out. Dorsal suture and lateral margins glossy black, with very fine punctation. Abdomen. Sternites finely punctate, covered by short, yellowish brown pilosity, except for a small central portion in the middle of sternites III-V. Legs. Fore tibiae shorter than in males, TL 15 mm, and shorter than tarsi, TF 17 mm; external sides with three strong teeth almost equal in length, with the subapical tooth a little longer. Lateral teeth and inner apical spur smaller than in males.


L: 52-60 mm; PL: 15-16 mm; PW: 23-27 mm; EL: 34-39 mm; EW: 30-34 mm; FL: 15-16 mm; TF: 17-18 mm; HL: 6-8 mm.














Megasoma (Megasoma) gyas (Jablonsky in Herbst, 1785)

Prandi, Massimo, Grossi, Paschoal C. & Vaz-De-Mello, Fernando Z. 2020

Megasoma gyas rumbucheri

Fischer 1968


Latreille 1807

Scarabaeus laniger

Olivier 1789

Scarabaeus gyas

Herbst 1785