Osoriellus sinuatoangularis, 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 : 242-243

Osoriellus sinuatoangularis n. sp.

( Figs 16 A-C, 20F)

Type material: Holotype, male: Peru: Tambopata Prov. , Madre de Dios Depto. , 15 km NE Puerto Maldonado, ReservaCuzcoAmazónico (12°33'S, 69°03'W), 200 melevation, Plot #Z2E15, 28.6.1989, leg. J.S. Ashe, R.A. Leschen, D. Silva, ex. flight intercept trap, #310 ( KNHM).

Paratype: female, with same data as holotype ( UIC); Madre de Dios, Cuzco Amazonica (69°2.6'W, 12°36.48'S), 300 m elevation, secondary forest W2, female, 17.5.1995, leg. D. Agosti ( AMNH) .

Diagnosis: The species can be identified by the short emargination at the posterior pronotal angles. At this pronotal part, the lateral margin ends without direct continuation to the posterior edge and, thus, forms a short emargination. In this respect it resembles O. subsinuatus . But O. subsinuatus has a distinct netlike pronotal microsculpture and matt surface, whereas the pronotum in O. sinuatoangularis has a weak microsculpture and shiny surface.

Description: Length: 4.5 mm. Colouration: Brown; elytra and abdomen lighter reddish brown; legs and antennae red.

Head: 0.62 mm long, 0.92 mm wide; eyes slightly prominent and slightly longer than temples; sides of fore-head narrowed to anterior angels in deep concave curve; sides of clypeus parallel; anterior angles of clypeus produced to acute long teeth; between lateral teeth front edge even; setiferous punctation irregularly dense; on fore-head sparser than on posterior head; wide midline and large area at base of antennae impunctate; on vertex, interstices between punctures as wide as diameter of punctures; microsculpture moderately deep and dense; surface slightly shiny.

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

Pronotum: 0.92 mm long, 0.95 mm wide; widest at smoothly rounded anterior angles; slightly convergent from anterior to posterior angles; shortly in front of posterior angles slightly stronger narrowed; lateral margin fine; in dorsal aspect, visible except a short part near anterior angles; lateral margin ending in front of posterior angles; posterior angles shortly emarginate and without margin; setiferous punctation large; in irregular rows; wide midline impunctate; within rows, interstices between punctures slightly shorter than diameter of punctures; between rows, interstices between punctures slightly wider; between coarse punctures with dense micro-punctation; microsculpture weaker than on head; surface shiny.

Elytra: 1.08 mm long, 0.96 mm wide; weak coriaceous ground sculpture; setiferous punctation sparser than on pronotum and in irregular rows.

Abdomen with dense setiferous punctation and wide impunctate midline; netlike microsculpture weak; surface shiny.

Protibia: 0.50 mm long, 0.20 mm wide; 9 spines on outer edge; apical spines not inserted on digits; WLR: 4.2; in posterior aspect, comb at inner emargination covered in central part; posterior face with dense setation.

Aedeagus with long apical lobe strongly curved to obtuse apex; laterally, at base of apical lobe with group of several sensillae.

Etymology: The specific name is a combination of the epithet sinuatus meaning emarginate and angularis meaning angle and refers to the shortly emargination at the posterior angles of the pronotum.

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.