Osoriellus infuscatus, 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 : 300-301

Osoriellus infuscatus n. sp.

( Figs 120 A-C, 124F)

Type material: Holotype, male: Peru: Tambopata Prov. Madre de Dios Depto., 15 km NE Puerto Maldonado, Reserva Cuzco Amazônica (69°03'W, 12°33'S), 200 m elevation, collected by flight intercept trap at Plot #Z1U16, 22.7.1989, leg. R.A. Leschen ( KNHM).

Paratypes: Peru: Pasco Dept., Villa Rica Rd. (75°18.54'W, 10°47.06'S), 1475 m elevation, collected by flight intercept trap, male, 15.- 18.10.1999, leg. R. Brooks & D. Brzoska ( UIC) ; Junin Dept, La Merced, 9.5 km NE La MercedVilla Rica Rd. (75°18.18'W, 10°58.42'S), 880 m elevation, collected by flight intercept trap, female, 15.- 21.10.1999, leg. R. Brooks ( KNHM) .

Diagnosis: From the similarly sized species, O. infuscatus can be differentiated by the digitate protibia and the weak pronotal microsculpture. It highly resembles O. lescheni and O. loreti and can be differentiated from O. loreti by the rounded shoulders and from O. lescheni by the pronotal microsculpture.

Description: Length: 4.0 mm. Colouration: Dark brown; posterior margin of pronotum and elytra lighter red with posterior margin darkend; abdomen and antennae light red; legs light brown.

Head: 0.56 mm long, 0.87 mm wide; eyes slightly prominent; nearly twice as long as temples; sides of fore-head convergent to anterior angles in slight sinuate curve; anterior edge even; setiferous punctation large but not deep and moderately sparse; supraocular area and neck with denser nearly coriacous punctation; wide midline on vertex, clypeus and area at base of antennae impunctate; on vertex interstices between punctures approximately as wide as diameter of punctures; on average, yellow setae slightly longer than interstices between punctures; without or extreme weak microsculpture; surface nearly polished.

Antennae slightly shorter than head and half of pronotum combined; second antennomere oval and slightly wider than conical third antennomere; width of following antennomeres increasing, but all antennomeres nearly quadrate.

Pronotum: 0.82 mm long, 0.93 mm wide; widest at anterior angles; anterior angles nearly rectangular; evenly convergent to posterior angels; anterior edge only 1.1 times as wide as posterior edge; posterior angles obtusely rounded; in dorsal aspect, lateral margin visible throughout its total length; very slightly widened close to posterior angles; setiferous punctation moderately deep and dense; wide midline impunctate; punctures in irregular rows; on average, interstices between punctures of row as wide as diameter of punctures; interstices between rows nearly twice as wide as diameter of punctures; between normal coarse punctures with dense micro-punctation; without microsculpture; surface nearly polished.

Elytra: 0.97 mm long, 0.93 mm wide; sides nearly parallel; shoulders nearly rectangular; setiferous punctation as deep and large as on pronotum; punctures in irregular rows; coriaceous ground-sculpture weak.

Abdomen with setiferous punctation weak and sparse; without microsculpture; surface shiny.

Protibia: 0.47 mm long, 0.15 mm wide; with 7 spines on outer edge; apical spines on short digits; WLR: 0.83; in posterior aspect, inner emargination with comb visible throughout its total length; posterior face sparsely covered by long yellow setae.

Aedeagus with apical lobe not longer than basal lobe; apical lobe moderately narrow and nearly straight; upper edge slightly curved; shortly in front of apex abruptly narrowed to obtuse apex; inner edge with sparse row of sensillae.

Etymology: The specific name infuscatus derived from the same Latin word meaning brownish and refers to the colouration of the species.

Figures

Fig. 119-122: Remaining-species-group: Osoriellus weberi (119), O. infuscatus (120), O. rectangulus (121), O. rufescens (122); antenna (A), protibia (B), aedeagus in ventral and lateral aspects (C); scale bar: 0.1 mm.