Osoriellus breviceps ( NOTMAN, 1925 ) 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 : 251-252

Osoriellus breviceps ( NOTMAN, 1925) new combination ( Figs 33 A-C, 41C)

Osorius breviceps NOTMAN, 1925: 7

Type material examined: Paraguay: San Bernardino , under stones, female, Dec. 27. 1927?, leg. K. Fiebig (holotype in NMNH).

Further material examined: Paraguay: Puerto Presidente Stroessner, Hungarian Soil-Zool.Exp. male, 26.12.1965, leg. Loksa ( NHMH).

Diagnosis: Within the O.- guiananus -group, O. breviceps is characterised by the trapezoidal shape of the pronotum and the short setae in the punctures. Concerning the microsculpture, O. breviceps resembles O. melancholicus and O. macrops , but the pronotal sides in O. melancholicus are slightly sinuate in front of the posterior angles and in O. macrops the sides are more convex. Thus, the posterior angles are nearly rectangular in O. melancholicus and more widely rounded in O. macrops , whereas they are forming obtuse angles in O. breviceps .

Description: Length: 6.5 mm. Colouration: Black; antennae and legs brown, tibiae yellow.

Head: 0.80 mm long, 1.20 mm wide; eyes distinctly prominent, slightly longer than temples; punctation on disc deep and moderately dense; punctures partly granulate; on posterior vertex interstices between punctures shorter than half of diameter of punctures; on anterior vertex, interstices between punctures wider; on average, slightly shorter than diameter of punctures; on supraocular area, eyes with striate punctation; surface with netlike microsculpture, slightly shiny.

Antennae short and thick; slightly longer than head; second antennomere oblong, third conical, but not longer than second; following three antennomeres approximately quadrate; seventh to tenth antennomeres distinctly wider than preceding antennomeres; wider than long.

Pronotum: 1.35 mm long, 1.40 mm wide; widest at anterior angles; evenly convergent to posterior angles; shape trapezoidal; lateral margin narrow, in dorsal aspect, close to anterior angles not visible; wider in posterior half, but still narrow; punctures deeper and larger than on head and with very short setae; on small part adjacent to midline coriaceous; on average, interstices between punctures half as wide as diameter of punctures; microsculpture netlike and weak; surface distinctly shinier than on head.

Elytra: 1.50 mm long, 1.40 mm wide; with coriaceous ground-sculpture; punctation much finer than on head, but still dense, hardly visible in deep groundsculpture.

Abdomen with dense setiferous punctation; microsculpture weak and netlike, surface more or less shiny.

Protibia: 0.53 mm long, 0.17 mm wide; outer edge with 7 spines; apical spines inserted on moderately long digits; WLR: 0.61; in posterior aspect, comb of inner emargination totally visible; posterior face sparsely covered by long yellow setae.

Aedeagus with moderately long, triangular apical lobe; apex of apical lobe shortly rounded; inner edge of apical lobe with sparse row of sensillae.

Figures

Fig. 32-37: Osoriellus-guiananus-group: Osoriellus guiananus (32), O. breviceps (33), O. solidus (34), O. macrops (35), O. melancholicus (36), O. diversus (37); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.