Osoriellus corniculatus, 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 : 241

Osoriellus corniculatus n. sp.

( Figs 18 A-D, 20H)

Type material: Holotype, male: Colombia: Putumayo, Villagarzon , 6.IX.1984, leg. M. Cooper ( BMNH).

Diagnosis: O. corniculatus is characterised by the specific structure of the clypeus. The clypeus is widely emarginate in the middle with shortly produced acute teeth in the angles. In the other species of the group, the space between the produced clypeal angles is either even or denticulate.

Description: Length: 5.2 mm. Colouration: black, legs and antennae light brown.

Head: 0.81 mm long, 1.07 mm wide; eyes not prominent; approximately as long as temples; sides in front of eyes deeply emarginate; sides of clypeus parallel; anterior angles of clypeus produced to broad prominence; prominences half as wide as emarginate space between them; outer angles of prominences produced to long acute teeth; setiferous punctation sparse on fore-head; much denser on vertex; wide midline and large area at base of antennae impunctate; on vertex, interstices approximately half as wide as diameter of punctures; on fore-head, interstices at least as wide as diameter of punctures; narrow netlike microsculpture distinct; surface slightly shiny.

Antennae slightly longer than head; second antennomere oblong; slightly longer than conical third; following antennomeres increasing in width; antennomeres four to ten approximately quadrate.

Pronotum: 1.02 mm long, 1.10 mm wide; widest at anterior angles; anterior angles approximately rectangular; sides slightly and evenly convergent to obtusely rounded posterior angles; lateral margin fine; in anterior half finer than in posterior half; in dorsal aspect, nearly invisible at anterior angles; setiferous punctation coarse and dense; row adjacent to impunctate midline with more than 10 punctures and interstices between punctures of row shorter than half of diameter of punctures; on disc, punctation moderately dense; interstices between punctures as wide as and half as wide as diameter of punctures; netlike microsculpture distinct; surface slightly shiny.

Elytra: 1.31 mm long, 1.16 mm wide; with coriaceous ground-sculpture; setiferous punctures in irregular rows; punctures nearly invisible in coarse ground-sculpture.

Abdomen with dense setiferous punctation; on tergites, narrow midline impunctate; with remains of irregular microsculpture; surface between punctures shinier than on fore-body.

Protibia: 0.65 mm long, 0.22 mm wide; with 7 spines at outer edge; apical spines inserted on short digits; WLR: 2.4; in posterior aspect, comb at inner emargination visible throughout its total length; posterior face sparsely covered by long yellow setae.

Aedeagus rectangularly angulate; apical lobe slender; inner edge of apical lobe with numerous sensillae.

Etymology: The specific name derives from the Latin word cornus meaning horn and refers to the structure of the anterior angles of the clypeus.

Figures

Fig. 16–19: Osoriellus-bicornis-group: Osoriellus sinuatoangularis (16), O. subsinuatus (17), O. corniculatus (18), O. sinuatus (19); antenna (A), protibia (B), aedeagus in lateral aspect (C), anterior edge of clypeus (D); scale bar: 0.1 mm.