Macrodactylus gracilis Moser, 1918

Arce-Pérez, Roberto & Morón, Miguel Ángel, 2014, New species and records of Macrodactylus Dejean (Coleoptera: Scarabaeidae: Melolonthinae: Macrodactylini) from Bolivia, Zootaxa 3857 (2), pp. 292-300 : 298-299

Macrodactylus gracilis Moser, 1918

( Figs. 20–21 , 26–29 )

Diagnosis. Body integument dark red; frons and antennal club black; clypeus, funicle, mouthparts, and legs reddish yellow. Body completely covered with scale-like, yellow, short setae; tarsi with rings of white setae; parameres glabrous.

Redescription. Male: Body length 8.2 mm; humeral width 2.30 mm. Color: Body dark red; clypeus intensely red; frons and antennal club black; funicle, mouthparts, and legs reddish yellow. Surface: Completely covered with scale-like, yellow, short setae that obscure the surface. Head: Form elongate.Clypeus trapezoidal, anterior border nearly straight.Antenna with funicle reddish yellow and club black. Labial palpi short. Mentum elongate and oval, longitudinally with wide furrow, with sparse setae on surface. Thorax: Pronotum hexagonal, dark red, convex; completely covered with yellow short setae that obscure the surface; wider than long (1.95: 1.90 mm). Prosternal process long, robust, curved, more robust at apex. Scutellum subtriangular, long, apex acute. Elytra yellowish red; completely covered with scale-like, yellow, short setae that obscure the surface. Metasternum wide, with dense and abundant rows of long, slender, clear yellow setae between mesocoxae and metacoxae. Abdomen: Sternites 2–5 concave, with dense rows of long, stout, clear yellow setae; length of sternite 5 twice length of sternite 4; sternite 6 ovate with sparse stout, long setae. Pygidium elongate, ovate, with setae evenly distributed. Legs: Profemur with subrectangular projection near base scarcely developed. Mesotibia widened toward apex; with 2 straight, acute spurs and long, stout setae around apex; largest spur with rounded apex and smaller spur with acute apex. Tarsi enlarge; apex black, with rings of white setae and long spine-like setae. All tarsal claws long and cleft. Genitalia: Total length 2.05 mm. Parameres long and slender, oval, glabrous; narrow and fused dorsobasally; enlarged and widened toward the apex; apex lanceolate; length 0.95 mm, width 0.60 mm ( Figs. 26–28 ).

Female: Body length 8.4 mm; humeral width 2.70 mm. Similar to males except as follows: Pronotum length 1.75 mm, width 2.15 mm, with elevated “X” pattern. Abdominal sternites convex without distinct setae; pygidium short, width, subtriangular. Genital plates long, oval, with apex asymmetric; length 0.90 mm, width 0.42 mm ( Fig. 29 ).

Material examined: Bolivia, Yungas, Coroico . Fassl, 1908, (1male, 1 female MHNW).

Natural history. No precise details on the habits of this species are available. It was described from “ Bolivia (Tonampayo)” but this location was not found in any other reference.

Remarks. Externally, M. gracilis is very similar to other South American species of Macrodactylus , but the sculpture of the female pronotum and shape of male and female genitalia help to distinguish this species.

Figures

FIGURES 18 – 21. Macrodactylus bolivianus: 18) dorsal view, 20) lateral view. Macrodactylus gracilis: 19) dorsal view, 21) lateral view.

FIGURES 22 – 29. Diagnostic structures of Macrodactylus bolivianus: 22) parameres, distal view, 23) parameres, lateral view, 24) basal piece, dorsal view, 25) female genital plates, ventral view. Macrodactylus gracilis: 26) parameres, distal view, 27) parameres, lateral view, 28) basal piece, dorsal view, 29) female genital plates, ventral view. Scales in mm.