Megaceras stuebeli Kirsch 1885

Alvarez, Héctor Jaime Gasca, da, Claudio Ruy Vasconcelos, Fonseca & Ratcliffe, Brett C., 2008, Synopsis of the Oryctini (Coleoptera: Scarabaeidae: Dynastinae) from the Brazilian Amazon, Insecta Mundi 2008 (61), pp. 1-62 : 35-38

Megaceras stuebeli Kirsch 1885

( Fig. 65-71 )

Megaceras stuebeli Kirsch 1885: 223

Megaceras chorinaeus amazonicum Frings 1929: 21 (synonym, described as variation)

DESCRIPTION. Length: 42.5-62.3 mm (males); 39.3-52.2 mm (females). Width: 21.2-32.1 mm (males); 21.5-28.8 mm (females). Color: Black.

Males. Head: Frons with long, recurved horn, apex strongly bifurcated, posterior margin of horn with small, tooth-like swelling near apex. Eye canthus with rounded apex, margin weakly crenulate, surface finely punctate. Clypeus truncate, border weakly crenulate, apex slightly bilobed ( Fig. 66 ), surface finely rugose. Antenna with 10 segments, club subequal in length to segments 2-7. Mandibles with 2 teeth, external tooth larger, with rounded apex, internal teeth with apex acuminate. Pronotum: Majors ( Fig. 67 ) with large, high, bifurcated protuberance, apex with 2 divergent horns strongly curved downward, fovea broad. Lateral margins with a band of spaced rugae, rugae connected to areola apposita. Minors ( Fig. 68 ) with smaller protuberance, apex with divergent tubercles projecting forward, bands of rugae in lateral margins reaching apex. Scutellum: Triangular , deep punctures distributed in central region. Elytra: Surface smooth, sutural stria impressed. Pygidium: Surface punctate. Base with band of long setae. Lateral angles rugose, in lateral view convex. Legs: Protibia tridentate. Apex of posterior tibia with a spur. First tarsomere of posterior tarsus triangular, apex extended into long spine Venter: Prosternal process long, convex, apex weakly acuminated to subquadrangular, with thick setae. Parameres: Oval, inner margins parallel, apex weakly dilated, rounded, setigerous ( Fig. 69-70 ).

Females. As males except in the following respects: Head: Frons with small conical tubercle, surface rugose. Pronotum: Surface smooth, lateral margins with punctures, and with 2 small tubercles behind anterior margin. Pygidium: Surface finely punctate with sparse setae.

DIAGNOSIS. The large pronotal protuberance with two horns strongly curved downward and the bifurcate apex of frontal horn, are characters that will distinguish M. stuebeli . Minor males could be confused with minor males of M. philoctetes , and it is necessary to examine the parameres to differentiate these species when the teeth of the apex of the clypeus in M. philoctetes are not well developed.

DISTRIBUTION. Megaceras stuebeli is an endemic species of the Amazon region, with records only for the Brazilian Amazon. Endrödi (1976) recorded this species from Reseva Ducke, Maués River, and Manaus- Itacoatiara km 26 in Amazonas state. Lauchame (1992) recorded Pará state without specific locality data.

LOCALITY RECORDS. ( Fig. 71 ) 130 specimens examined (62 males, 68 females). Specimens were seen from the following collections : INPA, CZPB, MZSP, MPEG, and UNSM.

AMAZONAS (106): Itacoatiara (Fazenda Aruana Am 10 km 215, Am 10 km 228), Manaus (Am 10 km 24, Am 10 km 45, Am 10 km 70, BR 174 km 45, BR 174 km 32, Cidade Nova, Distrito Industrial, Fazenda Dimona PDBFF, Reserva Ducke) Novo Airão (Rio Negro Paraná do Itauacu), Pedrinha, Presidente Figueredo (BR 174 Km 180, UHE Balbina, Rio Urubu), Taracuá (Rio Uaupés), Parque Nacional do Jaú (Rio Jaú), Rio Juruá. PARÁ (22): Açu (Tomé); Belém; Benevides; Castanhal (Estrada de Curuca km 8), Juriti, Ipixuna (Rio Capim), Marajó (Ponta Pedras), Marituba, Tucuruí. RONDÔNIA (2): Vilhena.

TEMPORAL DISTRIBUTION. January (12), February (25), March (5), April (8), May (7), June (15), July (12), August (10), September (6), October (7), November (9), December (5).

BIOLOGY. Adults are active at night and can be attracted to lights. In Brazilian Amazonia, adults have been collected from semi-humid ombrophilous forests, secondary forests, and floodplain areas from sea level to 600 meters.

Figures

Figure 71. Distribution of Megaceras stuebeli in Brazilian Amazonia.

Figure 65-70. Megaceras stuebeli. 65) Habitus. 66) Male head (dorsal view). 67) Male major. 68) Male minor (scale line: 5 mm). 69) Parameres frontal view. 70) Parameres lateral view (scale line: 1 mm).