Osoriellus bicornis, 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 : 240

Osoriellus bicornis n. sp.

( Figs. 14 A-D, 20A)

Type material: Holotype, male: Peru: Tambopata Prov., Madre de Dios Dpto., 15 km NE Puerto Maldonado, Reserva Cuzco Amazónico (12°33'S, 69°03'W), 200 m elevation, Z2 E15, flight intercept trap, 26.6.1989, leg. D. Silva & R.A. Leschen, #285 ( KNHM).

Diagnosis: The species can be easily identified by the produced truncate teeth of the clypeus. The other species with teeth-like produced angles of the clypeus are longer than 4 mm and teeth are acute.

Description: Length: 3.7 mm. Colouration: Light brown, except fore-head; posterior head darker brown; legs and antennae yellow.

Head: 0.56 mm long, 0.71 mm wide; eyes distinctly prominent; as long as temples; sides of fore-head narrowed to front edge in concave curve; anterior angles of clypeus produced to broad truncate teeth; teeth longer than onefourth of distance between them; setiferous punctation irregularly dense and deep; on vertex denser than on forehead; wide midline, area at base of antennae and transverse area on posterior vertex impunctate; on average on punctate areas, interstices between punctures distinctly shorter than diameter of punctures; with remains of weak microsculpture; surface slightly shiny.

Antennae as long as head and half of pronotum combined; second antennomere oblong; wider and nearly twice as long as conical third antennomere; following antennomeres increasing in width; fourth quadrate; fifth and sixth wider than long; sixth antennomere twice as wide as long; antennomeres 7 to 10 distinctly wider than preceding antennomeres and quadrate.

Pronotum: 0.67 mm long, 0.71 mm wide; widest at anterior angles; anterior angles shortly produced to acute teeth; sides evenly convergent to smoothly rounded posterior angles; in anterior half less narrowed than in posterior half; lateral margin fine; in posterior half slightly wider; in dorsal aspect, not visible close to anterior angles; setiferous punctation deep and sparser than on vertex of head; in irregular longitudinal rows; midline impunctate; on average, interstices between punctures of rows as wide as diameter of punctures; interstices between punctures wider than diameter of punctures; microsculpture deep, but not dense; surface slightly shiny.

Elytra: 0.87 mm long, 0.75 mm wide; setiferous punctation distinct; in rows; coriaceous ground-sculpture weak; surface less shiny than on pronotum and head. Abdomen with dense setiferous punctation; without impunctate midline; interstices between punctures with weak netlike microsculpture; surface shiny.

Protibia: 0.39 mm long, 0.11 mm wide; with 8 spines at outer edge; apical spines not inserted on digits; WLR: 3.5; in posterior aspect, comb at inner emargination nearly invisible in central part, but with very long setae at base; posterior face sparsely covered by yellow setae.

Aedeagus with smoothly curved apical lobe ending in obtuse apex; inner edge of apical lobe with row of sensillae in regular distances.

Etymology: The specific name derived from the Latin word meaning two horns and refers to the two horn-like truncate teeth of the clypeus.

Figures

Fig. 12-15: Osoriellus-bicornis-group:Osoriellus bovis (12), O. cornutus (13), O. bicornis (14), O. spinosus (15); antenna (A), protibia (B), aedeagus in lateral aspect (C), anterior edge of clypeus (D); scale bar: 0.1 mm.