Osoriellus cornutus, 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 : 241-242

Osoriellus cornutus n. sp.

( Figs 13 A-D, 20D)

Type material: Holotype, male: Panama: Cana Biological Station , Serrania de Pirre (77°41.06'W, 7°45.18'N), 1200 m elevation, flight intercept trap, 4.- 7.6.1996, leg. J. Ashe, R. Brooks, #PAN1AB96 105 ( KNHM).

Diagnosis: The species resembles O. bovis and O. notmani concerning the pair of acute teeth of the clypeus. It can be differentiated from O. notmani by the smaller size and from O. bovis by the matt surface of the pronotum.

Description: Length: 4.8 mm. Colouration: Black; lateral and posterior margin of pronotum, legs and antennae light brown.

Head: 0.76 mm long, 1.01 mm wide; eyes slightly prominent; as long as temples; sides of fore-head concave; sides of clypeus parallel; lateral angles of clypeus produced to acute triangular teeth; teeth longer than one-fourth of width between them; setiferous punctation fine and sparse; wide midline impunctate; interstices between punctures more than twice as wide as diameter of punctures; on supraocular area punctation denser; interstices between punctures as wide as diameter of punctures; isodiametric microsculpture deep and dense; surface matt.

Antennae slightly longer than head; second antennomere oval and slightly wider than conical third; antennomeres 4 to 6 as wide as third antennomere, but quadrate; antennomeres 7 to 10 wider than preceding antennomeres and also quadrate.

Pronotum: 0.99 mm long, 1.02 mm wide; widest at anterior angles; evenly narrowed to widely rounded posterior angles; lateral margin fine; in posterior half slightly wider than in anterior half; in dorsal aspect, invisible close to anterior angles; setiferous punctation deep and dense; short yellow setae pointing posteriad; wide midline impunctate; punctures in irregular rows; interstices between punctures of row as wide as diameter of punctures; interstices between rows 1.5 times as wide as diameter of punctures; isodiametric microsculpture deep and dense; surface matt.

Elytra: 1.24 mm long, 1.15 mm wide; with deep coriaceous ground-sculpture; setiferous punctation in irregular rows; punctures nearly invisible in coarse ground-sculpture.

Abdomen with fine setiferous punctation except on narrow impunctate midline; surface between punctures polished and shiny.

Protibia: 0.55 mm long, 0.17 mm wide; with 8 spines on outer edge; apical spines on short digits; WLR: 2.7; posterior face sparsely covered by long yellow setae; in posterior aspect, comb covered in central part.

Aedeagus with apical lobe evenly curved to obtuse apex; inner edge of apical lobe with nine sensillae.

Etymology: The specific name derives from the same Latin word meaning horned and refers to the pair of long acute 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.