Osoriellus melancholicus Irmler 2014, n. sp.

Osoriellus melancholicus n. sp.

(Figs 36 A-C, 41F)

Type material: Holotype, male: Peru: Dept. Loreto, Campamento San Jacinto (75°51.77'W, 2°18.75'S), collected by berlese extraction at Qd. 22, 175- 215 m elevation, 2.7.1993, leg. R. Leschen (KNHM).

Paratypes: Peru: 2 females with same data as holotype, but collected from flowerfall by berlese extraction and at 11.7.1993 (KNHM, UIC); Dept. Loreto, 1.5 km N Teniente Lopez (76°06.92'W, 2°35.66'S), 210-240 m elevation, collected by flight intercept trap, female, 24.7.1993, leg. R. Leschen (KNHM); Brazil: Amazonas, Manaus, 26 km N of Manaus, Reserva Ducke, collected by flight intercept trap, male, 1995-1996 (BNHM).

Diagnosis: Concerning the pronotal microsculpture, O. melancholicus can be confused with O. breviceps, but the shape of the pronotum is distinctly different. Additionally, the anterior edge of the clypeus is emarginate and not even as in O. breviceps.

Description: Length: 6.3 long. Colouration: Black; legs and antennae brown.

Head: 0.81 mm long, 1.24 mm wide; eyes slightly prominent; nearly twice as long as temples; sides of fore-head narrowed to anterior angles in smooth sinuate curve; anterior angles obtuse; anterior edge of clypeus deeply emarginate; punctation deep; central area on clypeus and area at base of antennae impunctate; on clypeus, interstices between punctures at least as wide as diameter of punctures; on vertex with denser punctation; centrally, interstices between punctures half as wide as diameter of punctures; laterally, interstices between punctures still shorter, partly coriaceous; punctures on clypeus with short yellow setae; punctures on vertex without setae, except one pair of setiferous punctures in centre close to neck and several setiferous punctures on supraocular area; without microsculpture; surface shiny.

Antennae as long as head and half of pronotum combined; second antennomere oval and as long as conical third; antennomeres four and five as wide as preceding antennomeres; width of following antennomeres increasing, but each antennomere approximately quadrate.

Pronotum: 1.24 mm long, 1.37 mm wide; widest shortly behind anterior angles; anterior angles obtuse and rounded; evenly narrowed to posterior angles; shortly in front of posterior angles slightly emarginate; posterior angles nearly rectangular and slightly produced laterad; lateral margin fine in anterior half; widened to posterior angles; in dorsal aspect; covered shortly close to anterior angles; deep and coarse punctation irregularly dense; near midline denser than laterally; impunctate midline narrow in anterior half and widened in posterior half; close to midline punctation nearly coriaceous; on lateral disc, interstices between punctures as wide as diameter of punctures or closer; punctures without setae; between normal coarse punctures with dense micro-punctation; very weak longitudinal reticulate microsculpture; surface slightly shiny.

Elytra: 1.51 mm long, 1.44 mm wide; shoulders shortly rounded; sides nearly parallel; punctation slightly finer than on pronotum; in irregular rows; ground sculpture deep; surface slightly shiny.

Abdomen with dense setiferous punctation; narrow midline impunctate; punctures partly granulate and on segment VII and VIII partly elongate; irregular microsculpture very weak; surface slightly shiny.

Protibia: 0.77 mm long, 0.20 mm wide; slender; with 7 spines on outer edge; apical spines inserted on long teeth; WLR: 0.36; in posterior aspect, inner emargination with comb visible throughout its total length; posterior face sparsely covered by long yellow setae.

Aedaegus thick; with basal lobe and apical lobe approximately equally long; apical lobe thick at base; then suddenly narrowed to thin apex; inner edge of apical lobe with dense row of sensillae; apical third of inner edge without sensillae.

Etymology: The specific name melancholicus derived from the same Latin word meaning dark and refers to the black colouration.