Osoriellus silvaticus n. sp.

(Figs 39 A-C, 42B)

Type material: Holotype, male: Ecuador: Orellana, Payamino Research Station (77°17.29'W, 0°26.36'S), 300 m elevation, tropical rainforst, collected by flight intercept trap, 30.7.- 12.8.2007, leg. Gillett (BMNH).

Diagnosis: The species resembles O. diversus of the O.- guiananus -group. It has no setiferous punctation, but only few punctures with setae. In this respect, it resembles species of the genus Osorius; but the posterior face of the protibia carries no spines. A similar shape of the pronotum with the slightly widened lateral margin in the posterior half is also found in some species of the remaining-species-group. O. silvaticus can be easily differentiated from these species by the absence of the setiferous punctation.

Description: Length: 6.9 mm. Colouration: Black, legs and antennnae dark brown.

Head: 0.78 mm long, 1.20 mm wide; eyes prominent; small; slightly shorter than temples; sides of fore-head narrowed to teeth-like produced anterior angles in deep sinuate curve; between acute anterior angles, anterior edge of clypeus even; punctation not setiferous; punctures weak and sparse; interstices between punctures at least as wide as diameter of punctures; on both clypeus and vertex four setiferous punctures each; punctation on supraocular area denser and deeper; partly coriaceous; netlike microsculpture extremely weak and partly absent; surface of vertex shiny.

Antennae slightly longer than head; second antennomere oblong; third cornical and slightly longer than second; third antennomere 1.5 times as long as fourth; fourth to sixth antennomere slightly longer than wide; following antennomeres distinctly thicker than preceding antennomeres and approximately quadrate.

Pronotum: 1.16 mm long, 1.34 mm wide; widest at anterior angles; anterior angles produced to shorth acute teeth; sides evenly convergent to posterior angles; slightly sinuate in front of posterior angles; lateral margin fine in anterior half, slightly widened in posterior half; shape approximately trapezoidal; punctation not setiferous; deeper and denser than on head; on average, interstices between punctures slightly shorter than diameter of punctures; indistinct narrow midline impunctate; netlike microsculpture deeper than on head; surface slightly shiny.

Elytra: 1.45 mm long, 1.51 mm wide; widest in posterior third; rectangular shoulders sligthly rounded; punctation not setiferous; weak and dense; hardly visible in deep coriaceous ground-sculpture; surface matt.

Abdomen without punctation, but each segment dorsally with pair of setiferous punctures on each side of middle; netlike microsculpture distinct, but not deep; surface slightly shiny.

Protibia: 0.69 mm long, 0.27 mm wide; with 8 spines on outer edge; apical three spines inserted on long digits; WLR: 0.50; in posterior aspect, comb at inner emargination widely covered; posterior face sparsely covered by moderately long setae.

Aedeagus symmetric with evenly curved apical lobe; approximately as long as basal lobe; dorsal edge of apical lobe slightly sinuate at apex; group of three sensillae close to apex on lateral side; inner edge of apical lobe with row of numerous sensillae.

Etymology: The specific name derived from the same Latin word and means living in the forest.