Coelosis bicornis ( Leske 1779 )

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 : 5-8

Coelosis bicornis ( Leske 1779)

( Fig. 1-7 )

Scarabaeus bicornis Leske 1779: 418

Geotrupes bicornis Fabricius 1801: 9 (redescription)

Coelosis bicornis recifensis Bourgin 1944: 137 (synonym, described as subspecies)

Scarabaeus codrus Olivier 1789: 179 (synonym)

Coelosis hippocrates Burmeister 1847: 216 (synonym)

DESCRIPTION. Length: 26.1-30.5 mm (males); 23.6-25.0 mm (females). Width: 13.7-15.1 mm (males); 13.1-15.0 mm (females). Color: Light to dark reddish brown.

Males. Head: Frons with recurved horn, apex acuminate, posterior margin with small, tooth-like swelling near apex. Male minors with horn slightly recurved. Eye canthus rounded at apex, anterior margin crenulate with row of setae. Clypeus subtriangular, surface strongly rugose, apex with 2 teeth. Mandibles with 3 strong, sharp teeth. Antenna with 10 segments, club subequal in length to segments 2- 7. Pronotum: Surface in central third smooth, with deep, small punctures, sides strongly rugose. Male majors ( Fig. 2 ) with 2 subparallel horns, curving forward. Fovea prominent, surface with small punctures. Male minors with protuberance only. Elytra: Surface between suture and humerus with 5-8 punctate striae; punctures deep, ocellate. Apex with 2 small protuberance. Pygidium: Surface strongly setose, punctate. In lateral view, strongly convex. Legs: Protibia tridentate. Apex of metatibia weakly crenulate, lacking teeth. Metatarsus with apex of first tarsomere triangularly produced, spur-like. Venter: Prosternal process long, triangular, with prominence on posterior surface ( Fig. 3 ). Parameres: Basal region long, central region weakly concave in lateral view, apical region elongated and thin, apex narrow, recurved ( Fig. 5-6 ).

Females. As males except in the following respects: Head: Frons with surface strongly rugose, with small tubercles. Pronotum: Surface lacking horns or tubercles, completely punctate ( Fig. 4 ). Pygidium: Surface slightly punctate, densely and finely setose.

DIAGNOSIS. Coelosis bicornis can be distinguished by the two subparallel horns, clypeus with two teeth, tridentate mandibles, and a prosternal process with a strong prominence on the posterior surface.

DISTRIBUTION. Coelosis bicornis is widely distributed in South America, occurring from Colombia to the south of Argentina.

LOCALITY RECORDS. ( Fig. 7 ) 19 specimens examined (13 males, 6 females). Specimens were seen from the following collections : INPA, CZPB, MPEG, UNSM.

MATO GROSSO (3): Barra do Tapirapé. PARÁ (10): Alter do Chão, Belém (Utinga), Tucuruí (Rio Tocantins, Ilha Tocantins); Parque Indígena Tumucumaque (Rio Parú de Leste), alto Tapajós (Rio Cururú). RONDÔNIA (5): Ariquemes. RORAIMA (1): Amajari (Ilha de Maraca, Rio Uraricoera).

TEMPORAL DISTRIBUTION. January (2), February (1), April (1), June (1), July (3), August (2), September (3), November (6).

NOMENCLATURAL REMARKS. Coelosis bicornis was described by Leske in 1779. Burmeister (1847) recognized Coelosis hippocrates , described by Blanchard in 1846, as a synonym of C. bicornis . In subsequent works, Bourgin (1944) and Endrödi (1976) considered C. hippocrates and C. biloba as different species. In a phenetic analysis, Iannuzzi and Marinoni (1995) indicated that the number of different characters between C. hippocrates and C. bilo ba was small. It seems necessary for more phylogenetic research to determine the validity of C. hippocrates Blanchard as a species.

BIOLOGY. Nothing is known of the life history of C. bicornis and of other species of the genus; most available information refers to C. biloba . Larvae presumably feed on organic matter in rotten trunks ( Iannuzzi and Marinoni 1995). Adults can be collected using light traps. Coelosis bicornis occurs from sea level to about 200 meters in elevation, and it is associated with ombrophilous forests, areas of degraded vegetation, and flooded areas.

Figures

Figure 7. Distribution of Coelosis bicornis in Brazilian Amazonia.

Figure 1-6. Coelosis bicornis. 1) Habitus. 2) Male head and pronotum (scale line: 5 mm). 3) Prosternal process. 4) Female pronotum dorsal view. 5) Parameres frontal view. 6) Parameres lateral view (scale line: 1 mm).