Enema pan ( Fabricius 1775 )

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 : 13-15

Enema pan ( Fabricius 1775)

( Fig. 15-20 )

Scarabaeus pan Fabricius 1775: 5

Scarabaeus chorinaeum Fabricius 1775: 5 (synonym)

Scarabaeus quadrispinosus Fabricius 1781: 11 (synonym)

Scarabaeus enema Fabricius 1787: 4 (synonym)

Scarabaeus aeneas Kirby 1818: 399 (synonym)

Scarabaeus titornus Perty 1830: 45 (synonym)

Enema lupercus Chevrolat 1843: 28 (synonym)

Enema infundibulum Burmeister 1847: 234 (synonym)

DESCRIPTION. Length: 45.0- 58.5 mm (males); 43.4-53.6 mm (females). Width: 23.5-31.6 mm (males); 24.44-31.6 mm (females). Color: Black, occasionally dark reddish brown.

Males. Head: Frons with long, recurved horn, flattened on sides, largest specimens with small tooth on posterior edge. Eye canthus with apex weakly acuminate, anterior margin weakly crenulate, surface punctate. Surface of clypeus densely punctate, sides narrow and emarginate, apex broad and emarginate. Antenna with 10 segments, club subequal in length to segments 2-7. Mandibles broad, apex strongly bidentate. Pronotum: Male majors with surface rugose except for pronotal depression and knob, depression smooth with dense micropunctures; horn on posterior half of pronotum with anteriorly projecting, bifurcate process. Male minors similar except discal depression densely punctate, punctures small; posterior half densely punctate with a bifurcate tubercle. Sides of horn punctate, with a non-rugose region. Elytra: Surface with strongly impressed, crenulate, sutural stria. Discal area smooth, with dense micropunctures. Sides with large, dense, ocellate punctures in anterior half. Pygidium : Base with transverse band of large, setigerous punctures; setae long, reddish brown. Apical margins rugose. Surface convex in lateral view. Legs: Protibia quadridentate, occasionally with all teeth equidistant. Apex of posterior tibia weakly crenulate and with large tooth. Basal segment of posterior tarsus triangularly elongated at apex. Venter: Prosternal process short, triangular, apical half setigerous. Parameres: Simple, elongate, oval. ( Fig. 18-19 ).

Females: Similar to male minors, head horn reduced.

DIAGNOSIS. This species can be recognized by the well developed frontal and pronotal horns in the males, and by the more elongated prosternal process. In Brazilian Amazonia, there are two morphotypes that show different horn morphology. The most common morphotype and has the pronotal horn bifurcate or bilobed and the frontal horn acuminate and recurved ( Fig. 16 ); other specimens have the pronotal horn long and acuminate, and the frontal horn is weakly bilobed in the apex ( Fig. 17 ).

DISTRIBUTION. Enema pan is widely distributed in South America, from Colombia to northern Paraguay ( Endrödi 1985). There are some records for Mexico and Central America ( Bates 1888); Ratcliffe (2003) and Ratcliffe and Cave (2006) found new records for Costa Rica, Panama, and Honduras.

LOCALITY RECORDS. ( Fig. 20 ) 395 specimens examined (244 males, 151 females). Specimens were seen from the following collections : INPA, CZPB, MZSP, IBSP, MPEG, UNSM.

ACRE (8): Purús (Selva Alto), Rio Branco. AMAZONAS (339): Barcelos (Reserva Urini, Rio Urini Lago Três Bocas), Benjamin Constant (Rio Javari), Canutama (Nova Vista, igarape Gyssua), Carauarí, Coari (Rio Urucu), Eirunepe (Rio Juruá), Humaita, Itacoatiara (Fazenda Saracá), Manaus (Am 10 km 37, INPA, UFAM), Manicoré, Maraã, Maués, Novo Airão (Ramal do Olimpo), Parintins, Parque Nacional do Jau, Presidente Figueredo (UHE Balbina), São Gabriel da Cachoeira, São Paulo de Olivença, Silves, Tefé, Uariní. MATO GROSSO (12): Barra do Tapirapé, Reserva Humboldt, Xavantina. PARÁ (14): Altamira (Castelo dos Sonhos), Cachimbo, Gorotire (Rio Fresco), Itaituba (Santaremsinho, Rio Tapajós), Novo Progresso, Óbidos, Redenção, Serra Norte (Serraria, Pojuca, Caldeirão). RONDÔNIA (21): Porto Velho, Vilhena. RORAIMA (1): Amajari (Ilha de Maracá, Rio Uraricoeira).

TEMPORAL DISTRIBUTION. January (2), February (4), March (2), April (1), June (5), July (3), August (18), September (41), October (156), November (148), December (7).

NOMENCLATURAL REMARKS. Endrödi (1976, 1985) and other authors recognized four morphotypes based in differences in the male pronotal and head horns. These morphotypes are considered synonyms of E. pan and represent substantial variation within a single species ( Ratcliffe 2003).

BIOLOGY. The life history of E. pan is mostly unknown. Adults are active at night and can be attracted to lights. During June to July and October to November, numerous adults were collected in Parque Nacional do Jaú in primary forest ( Andreazze 2001) and at Coari on the Urucú River (N. O. Aguiar 2008, personal communication). In the Brazilian Amazon, they have been collected from elevations ranging from sea level to 400 m in semi-humid ombrophilous forests, savannahs, and areas of seasonal whitewater inundation forest (várzea).

Figures

Figure 20. Distribution of Enema pan in Brazilian Amazonia.

Figure 15-19. Enema pan. 15) Habitus. 16) Male head and pronotum of the common morphotype (scale line: 5 mm). 17) Male head and pronotum of the less-common morphotype (scale line: 5 mm). 18) Parameres frontal view. 19) Parameres lateral view (scale line: 1 mm).