Osoriellus lescheni, 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 : 301

Osoriellus lescheni n. sp.

( Figs 115 A-C, 125B)

Type material: Holotype, male: Peru: Dept. Loreto, 1.5 km N Tienente Lopez (76°06.92'W, 2°35.66'S), 210-240 m elevation, near Ganoderma , 21.7.1993, leg. R. Leschen ( KNHM).

Paratypes: Peru: 2 males, 3 females with same data as holotype ( KNHM, UIC) .

Diagnosis: Among the species with long digits at outer edge of the protibia, O. lescheni is characterised by the light brown colouration and the polished surface. In particular, the shape of the aedeagus of O. lescheni is unique among the Neotropical Osoriellus species. The narrow apical lobe forming an acute angle to basal lobe was found in no other Neotropical species.

Description: Length: 4.6. Colouration: Dark brown; elytra dark reddish brown; posterior edge of pronotum and abdomen lighter, reddish; legs and antennae yellowish brown.

Head: 0.62 mm long, 0.92 mm wide; eyes not prominent; slightly longer than temples; sides of fore-head convergent to anterior angles in smooth concave curve; anterior edge of clypeus slightly sinuate; setiferous punctation moderately deep and dense; on fore-head sparser than on vertex; on supraocular area still denser; coriaceously punctate; on clypeus, at base of antennae and on transverse oval area close to neck impunctate; on vertex, interstices between punctures less than half as wide as diameter of punctures; on clypeus, yellow setae approximately as long as interstices between punctures; dense isodiamteric microsculpture irregular; on clypeus, denser than on vertex; surface matt; impuncate areas close to neck and at base of antennae polished, without microsculpture; surface shiny.

Antennae slightly longer than head; second antennomere oval and slightly thicker than shorter conical third antennomere; antennomeres 4 to 6 as wide as third antennomere, but quadrate; following antennomeres much wider than preceding antennomeres, but also approximately quadrate.

Pronotum: 0.89 mm long, 1.01 mm wide; widest in anterior third; slightly convergent to rectangular anterior angles; more strongly convergent to posterior angles in slight concave curve; posterior angles obtuse, but nearly rectangular; lateral margin finer in anterior half than in posterior half; slightly widened to posterior angles; setiferous punctation deeper, but sparser than on head; on average, interstices at least as wide as diameter of punctures; in irregular row adjacent to impunctate midline, interstices shorter; short yellow setae slightly shorter than interstices between punctures; between normal coarse punctures with sparse micro-punctation; without microsculpture; surface polished.

Elytra: 1.08 mm long, 1.03 mm wide; shoulders rounded, but nearly rectangular; sides slightly widened to posterior third; setiferous punctation approximately as dense and deep as on pronotum; in irregular rows; coriaceous ground-sculpture weak.

Abdomen with dense setiferous punctation; narrow midline on tergites impunctate; netlike microsculpture weak; surface slightly shiny.

Protibia: 0.50 mm long, 0.11 mm wide; slender, outer edge with 7 spines; apical spines inserted on long digits; WLR: 0.63; in posterior aspect, inner emargination with comb visible throughout its total length; posterior face sparsely covered by long yellow setae.

Aedeagus asymmetric; angulate; basal lobe thick; apical lobe slender and strongly curved; ending in acute apex; group of sensillae at base of apical lobe and on inner edge with numerous sensillae.

Etymology: The specific name derived from the name of the collector Richard Leschen to whom this interesting species is dedicated.

Figures

Fig. 114-118: Remaining-species-group: Osoriellus neotropicus (114), O. lescheni (115), O. loreti (116), O. digitatus (117), O. opticus (118); antenna (A), protibia (B), aedeagus in ventral and lateral aspects (C); scale bar: 0.1 mm.