Osoriellus oculatus ( SHARP, 1876 ) 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 : 238-239

Osoriellus oculatus ( SHARP, 1876) new combination ( Figs 7 A-D, 11C)

Osorius oculatus SHARP, 1876: 386

Type material examined: Brazil: Tefé (64°41'W, 3°21'S), without further data (holotype BMNH) .

Further material examined: Brazil: Mato Grosso, Cáceres (54°42'W, 16°03'S), 3 females, 7 males, 2./ 4.12.1955, leg. M. Alvarenga ( UIC) .

Diagnosis: Within the O.- oculatus -group, the species is characterised by its prominent eyes and the 3 short teeth on each side of the middle at anterior edge of the clypeus. The punctation of the pronotum is similar as in O. hanagarthi , but the shape of the pronotum is different. In O. oculatus , the pronotum is more deeply sinuated shortly in front of the posterior angles than in O. hanagarthi . The aedeagi are very similar in O. oculatus and O. hanagarthi , but the apex of the aedeagus in O. hanagarthi is obtuse, whereas it is acute O. oculatus .

Description: Length: 4.2 – 4.7 mm. Colouration: Dark brown; legs and antennae reddish.

Head: 0.60 mm long, 0.85 mm wide: with large and prominent eyes; eyes at least half as long as temples; angles of clypeus produced to short teeth; adjacent to tooth two smaller granules; middle not granulate, but slightly produced; clypeus and disc densely and coarsely punctate; interstices between punctures almost one-fourth as wide as diameter of punctures; large supraocular and indifferent area on vertex impunctate; surface moderately shiny; on parts of vertex indistinct weak microsculpture present.

Antennae with oblong second antennomere; third antennomere conical; one-fourth shorter than second; antennomeres 4 to 6 quadrate and equal in width; antennomeres 7 to 11 much wider and longer than preceding ones, slightly wider than long.

Pronotum: 0.80 mm long, 0.85 mm wide; widest at anterior angles, in anterior two-third slightly narrowed; in posterior third more strongly convergent to posterior angles; posterior angles obtusely rounded; lateral margin fine; in dorsal aspect, not visible at anterior angles; surface with large and deep setiferous punctures; interstices between punctures approximately half as wide as diameter of punctures; at each side of wide impunctate midline with row of 10 to 11 punctures partly forming coriaceous furrow; without microsculpture, but with sparse micro-punctation; surface shiny.

Elytra: 1.0 mm long, 0.90 mm wide; with dense, partly coriaceous setiferous punctures; punctures forming irregular rows; punctation laterally sparser than on disc; surface shiny, but partly with weak coriaceous groundsculpture.

Abdomen with dense setiferous punctation; setae pointing to middle; interstices between punctures less than one-fourth of diameter of punctures.

Protibia 0.48 mm long, 0.17 mm wide; with 9 spines at outer edge; apical spines inserted on short digits; WLR: 2.1; in posterior aspect, comb at inner emargination visible, but partly covered in apical part; on posterior face with dense setation.

Aedeagus stout with short apical lobe and four sensillae at inner edge.

Figures

Fig. 6-10: Osoriellus-oculatus-group: Osoriellus ocularis (6), O. oculatus (7), O. hanagarthi (8) O. sexdentatus (9) O. denticornis (10); antenna (A), protibia (B), aedeagus in lateral aspect (C), anterior edge of clypeus (D); scale bar: 0.1 mm.