Osoriellus cornifrons, 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 : 249-250

Osoriellus cornifrons n. sp.

( Figs 30A, C , 31C )

Type material: Holotype, male: Ecuador: Sucumbios, Sacha Lodge (76.05°W, 0°.05' S), sampled by Malaise trap, male, 27.8. - 10.9.1994, leg. W. Hibbs ( KNHM).

Paratypes: Ecuador: Sucumbios, Sacha Lodge (0°28.14'S, 76°27.35'W), 270 m elevation, sampled by flight intercept trap, male, 21.- 24.3.1999, leg. R. Brooks, #ECU1B99047 (head an pronotum lost) ( KNHM) ; Sucumbios Prov., Sacha Lodge (0.5°S, 76.5°W), 250 m elevation, collected by flight intercept trap, 2 males, 26.- 28.10.2004, leg. G. de Rougemont ( UIC) ; Prov . Napo, Tiputini Res. Stat. (76°09'W, 0°38'S), flight intercept trap, 1 male, 2 females, 5- 25.09.2000, leg. D.J. Inward & K.A. Jackson ( BMNH) .

Diagnosis: Among the three species of the O.- granarius - group, O. cornifrons resembles O. anceps in the structure of the head. It is distinctly smaller than O. anceps and as large as O. granarius . The aedeagus also resembles O. granarius , but the long acute, hook-like apex is asymmetric.

Description: Length: 6.9 mm. Colouration: Black; legs and antennae dark brown.

Head: 0.93 mm long, 1.34 mm wide; eyes slightly prominent; sides of fore-head shortly emarginate; sides of clypeus parallel; anterior edge of clypeus widely emarginate; anterior angles broadly produced and each ending in short acute tooth; setiferous punctation irregularly dense and moderately deep; on clypeus and at neck denser than on vertex; area at base of antennae impunctate; supraocular punctures granulate; microsculpture distinct; netlike on vertex and clypeus; longitudinally reticulate on impunctate area at base of antennae; surface matt.

Antennae slightly longer than head; second antennomere oval; as long as conical third; following antennomeres approximately quadrate and slightly increasing in width.

Pronotum: 1.35 mm long, 1.38 mm wide; widest at anterior angles; evenly narrowed in smooth curve to posterior angles; posterior angles widely rounded; lateral margin finer in anterior half than in posterior half; in dorsal aspect, not visible slightly behind anterior angles; setiferous punctation large, deep and coarse; punctures much larger than on head; midline impunctate; on average, interstices between punctures half as wide as diameter of punctures; netlike microsculpture deep, but wider than on head; surface slightly shiny.

Elytra: 1.57 mmlong, 1.42 mmwide; setiferouspunctation dense and in irregular rows; coriaceous ground-sculpture weak; punctures distinctly visible; surface more shiny than on pronotum.

Abdomen with dense setiferous punctation; netlike microsculpture on anterior tergites much denser and deeper than on posterior tergites; surface moderately shiny.

Protibia: 0.71 mm long, 0.24 mm wide; thick and nearly semicircular, 10 spines at outer edge; apical spines on short digits; WLR: 1.4; in posterior aspect, inner comb of emargination visible throughout its total length; posterior face with dense setation; on average, setae as long as half of protibial width.

Aedeagus oval; rectangularly angulate; apical lobe triangular, long and asymmetric; apex acute and curved.

Etymology: The specific name is a combination of the epithet cornus meaning horn and frons meaning front of head and refers to the two prominent lobes on both sides of the clypeus.

Figures

Fig. 28-30: Osoriellus-granarius-group: Osoriellus granarius (28), O. anceps (29), O. cornifrons (30); antenna (A), protibia (B), aedeagus in ventral and lateral aspect (C); scale bar: 0.1 mm.

Fig. 31: Osoriellus-granarius-group: Head, pronotum and elytra of Osoriellus granarius (A), O. anceps (B), O. cornifrons (C); scale bar: 0.5 mm.