Gracilaclopus crepuscularis Ocampo & Mondaca, new species

(Figs. 12–14, 26, 31)

Diagnosis. This species is distinguished from the other species of Gracilaclopus by the following combination of characters: labral shape subcircular, apex rounded, slightly reflexed lacking indentation or teeth; body bicolored; size> 6.0 mm; male genitalia as Fig. 26.

Description. Holotype male. Length 6.01 mm, width 2.80 mm. Color: Head, pronotum black; elytra brown; legs, antennae, and mouthparts brown; ventral surface brown. Head (Fig. 12): Eye canthus well developed; apex reflexed, with tooth; canthus bearing 3–5 setae, setae moderately long; frontocanthal carina not developed. Frons flat, surface sparsely punctate, glabrous. Clypeus transverse; surface densely punctate; lateral margins oblique; anterior margin straight, frontal area of anterior margin on same plane as clypeal disc; frontoclypeal suture obsolete. Labral shape subcircular; apex rounded, slightly reflexed; surface glabrous. Pronotum (Fig. 13): Surface sparsely punctate, disc with two patches of few setae on each side; setae long, slender. Marginal bead present in all margins, reduced on posterior margin. Anterior angle acute; posterior angles broadly rounded. Scutellum: Triangular, apex rounded, surface punctate and setose at base, smooth at apex. Elytra (Fig. 14): Surface punctate; punctures sparse, setose; setae moderately long. Legs (Fig. 14): Protibiae with two teeth, protibial spur not developed. Mesotibiae and metatibiae with two transverse carinae. Mesotibial and metatibial apex with fringe of spine-like setae. Male genitalia (Figs. 26 a–b): Parameres longer than phallobase, slightly curved, apex acute.

Remarks. Only males are known. Paratypes vary only slightly in length (6.0– 8.6 mm).

Type material. Holotype male at IAZA labeled: ARGENTINA: La Rioja / Anillaco (2 km N) RN 75 / 1310m / S28°47’17”, W66°55’01” / Jan-6-2002. F. C. Ocampo”; “ Gracilaclopus / crepuscularis / Ocampo & Mondaca / HOLOTYPE ” (red label). Paratypes (all male). Three paratypes labeled as holotype except for paratype label. One paratype at IMLA labeled: “TUCUNUCO / San Juan / Argentina / 29,30 enero- 1970 / Coll: E. Peña”. One paratype at IAZA (preserved in 95°etOH at -20°C) labeled: ARGENTINA: Mendoza / Dique El Carrizal, 823 m / S33°17’30” W68°44’32” / Jan-2-2002, F. C. Ocampo & K. Philips col.” All paratypes labeled: Gracilaclopus / crepuscularis / Ocampo & Mondaca / PARATYPE ” (yellow label).

Etymology. The species is named crepuscularis, or dusk, in reference to the time of the day when males were observed flying.

Distribution (Fig. 31). ARGENTINA. La Rioja: Anillaco (2 km N on RN 75) (4). Mendoza: Dique El Carrizal (1). San Juan: Tucunuco (1).

Temporal distribution. January (6).