Osoriellus orbiculatus, Irmler, 2014

Irmler, Ulrich, 2014, The Neotropical species of the genus Osoriellus FAGEL, 1959 (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (2), pp. 231-354 : 305

Osoriellus orbiculatus n. sp.

( Figs 107 A-C, 125E)

Type material: Holotype, male: Ecuador: Sucumbios, Sacha Lodge (76°27.35'W, 0°28.14'S), 270 m elevation, collected by flight intercept trap, 21.- 24.3.1999, leg. R. Brooks, #ECU1B99 047 ( KNHM).

Paratypes: Ecuador: Napo, Jatun Sacha Biol. Station , 21 km E. Puerto Napo (77°36.85'W, 1°04.10'S), lowland rainforest, 400 m elevation, collected by flight intercept trap, 2 males, 1 female, 7.7., 18.7. & 20.7.1994, leg. F. Génier ( KNHM, UIC) .

Diagnosis: Among the species with digitate protibia, the species resembles O. opticus by the large and thick eyes. The differences between these two species and to O. oculatus and O. ocularis are described under O. opticus .

Description: Length: 4.5 mm. Colouration: Brown; head and pronotum dark brown; posterior margin and posterior third of lateral margin yellowish brown; elytra light brown with darkened posterior margin; abdomen, legs and antennae yellowish brown.

Head: 0.61 mm long; 0.95 mm wide; eyes thick and distinctly prominent; nearly four times as long as temples; sides of fore-head narrowed to anterior angles in smooth sinuate curve; anterior edge of clypeus even; setiferous punctures large, but sparse; wide midline and area at base of antennae impunctate; on average, interstices between punctures as wide as diameter of punctures; on clypeus, interstices between punctures slightly wider than on vertex; isodiameteric microsculpture moderately deep and dense; surface slightly shiny.

Antennae slightly longer than head and half of pronotum combined; oval second antennomere slightly thicker than conical third, but both antennomeres equally long; following antennomeres increasing in width, but each antennomere approximately quadrate.

Pronotum: 0.85 mm long, 0.98 mm wide; widest shortly behind anterior angles; evenly convergent to posterior angles; posterior angles obtuse and shortly rounded; lateral margin fine in anterior half; distinctly widened in posterior half; in dorsal aspect; close to anterior angles nearly totally covered; setiferous punctures large; in row adjacent to wide impunctate midline denser than posteriad; interstices between punctures in central rows as wide as diameter of punctures or shorter; on disc, interstices between punctures at least as wide as diameter of punctures or slightly wider; between normal coarse punctures with denser micro-punctation; isodiametric microsculpture weak and dense; surface slightly shiny.

Elytra: 1.11 mm long, 1.08 mm wide; shoulders widely rounded; sides widest in posterior third; deep setiferous punctation in irregular rows; coriaceous ground-sculpture deep; surface slightly shiny.

Abdomen with dense and weak setiferous punctation; wide midline impunctate; netlike microsculpture weak; surface shiny.

Protibia: 0.51 mm long, 0.14 mm wide; with 9 long spines on outer edge; apical spines inserted on long digits; WLR: 0.75; in posterior aspect, inner emargination with comb visible throughout its total length; posterior face sparsely covered by long yellow setae.

Aedeagus angulate in obtuse angle; basal lobe short; apical lobe nearly twice as long as basal lobe; evenly convergent to obtuse apex; inner edge of apical lobe with few sensillae; denser at base and sparser to apex.

Etymology: The specific name orbiculatus derived from the same Latin word meaning circular and refers to the prominent semi-circular eyes.

Figures

Fig. 103-108: Remaining-species-group: Osoriellustrinitatis (103), O. carinicollis (104), O. sticticus (105), O. acutus (106), O. orbiculatus (107), O. adustus (108); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.