Bioacoustics of Bothynus tricornis

Redescription . Male . Body length : 25.0– 30.1 mm . Body width : 11.0–13.0 mm. Color : Completely dark ( Fig. 3 A–C). Head : Clypeus subpentagonal, moderately arched at middle, surface densely rugopunctate, with scarce setae on sides, apical half strongly constricted laterally, basal half with subparallel raised sides. Frontoclypeal suture with 2 strong, slender tubercles. Interocular width equals 2.4 transverse eye diameters; frontal surface densely rugopunctate, setose on sides. Eye canthus subtriangular. Mouthparts : Mandibles bidentate, teeth conic, strong. Maxilla with quadridentate galea; 1 strong tooth at apex, apical, 3 moderate teeth at base. Pronotum : Horned, with 3 remarkable upcurved horns (1 horn on each side, 1 horn on apex); concavity strongly deep, broad, occupying about ½ of pronotal area. Major males with bifurcated horns; apical horn exceeding the head length, covering it partially in dorsal view ( Fig. 3A ). Median males with weak apical bifurcation; apical horn not exceeding the head length ( Fig. 3B ). Minor males with pronotal tubercles instead of horns ( Fig. 3C ). Pronotal surface finely punctate, with few setae scattered on anterior area; anterior angles strongly constricted in frontal view. Scutellar shield : From parabolic to subtriangular. Elytra : Nearly completely smooth, striae barely marked, punctures only observed under 90X magnification. Venter : Hypomeron strongly emarginate in ventral view ( Fig. 3E ). Legs : Metatibia with spatulate internal spur. Abdomen : Ventrites I–II completely setose, III–IV with an incomplete row of setose punctures, V with a complete row of punctures, VI bordered with long setae on apex. Stridulatory apparatus of tergite VII with 2 bands of finely carinae, interrupted by a mid-line nearly reaching the apical margin. Tergite VIII rugopunctate on sides, discal area weakly punctate or smooth. Aedeagus : Parameres in caudal view ( Fig. 8C ), basal half with rounded outer sides, middle area strongly constricted on sides, apical half with divergent lateral flaps. In lateral view, apex downcurved, obtuse ( Fig. 9C ). Female ( Fig. 3D ). Body length : 23.8–27.1 mm . Body width : 14.5–15.0 mm. Female differs from male in the following aspects: Head : Frons with slightly convex basal area. Pronotum: Simple convex, anteriorly with a small apical tubercle followed by a shallow concavity confined to anterior area; anterior angles densely punctate; concavity densely covered with coalescent punctures ( Fig. 10C ); discal area moderately punctate. Legs : Inner protarsal claw simple, similar to outer claw. Abdomen : Ventrite VI triangular. Tergite VIII with subtrapezoidal shaped apical invagination, transverse about 7.9 times wider than long ( Fig. 11C ). Geographic distribution : Brazil : Minas Gerais , Rio de Janeiro ( Fig. 12C ). Bothynus tricornis occurs in transitional areas between Atlantic rainforest and Cerrado, with some occurrence from the Brazilian Atlantic coastal rainforest. It is apparently a rare species, which has not been collected nor registered in literature since Endrödi (1969 , 1985 ) (who also cited records from the states of Espírito Santo and Santa Catarina ). Recently a population was found in the north of Minas Gerais .