Osoriellus grossopunctatus, 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 : 270

Osoriellus grossopunctatus n. sp.

( Figs 56 A-C, 95D)

Type material: Holotype, male: Paraguay: Hungarian Soil-Zool. Exp. Puerto Presidente Stroessner, 2.1.1966, leg. I. Loksa ( NHMH).

Paratypes: 2 males, 1 female with the same data as the holotype ( NHMH, UIC) .

Diagnosis: The species is characterised by the large prominent eyes and in this respect it resembles O. surinamensis and O. asperatus . The last species have either a denser and finer or a coriaceous pronotal punctation. Concerning the large eyes, it also resembles O. ocularis and O. oculatu s of the O.- oculatus -group, but in O. grossopunctatus the anterior edge of the clypeus is even and not denticulate as in those two species. Compared to O. micros with smaller eyes, O. grossopunctatus has a more triangular pronotum and a larger and coarser pronotal punctation.

Description: Length: 3.5 mm. Colouration: Brown; elytra light reddish; legs and antennae yellow.

Head: 0.50 mm long, 0.64 mm wide; eyes distinctly prominent; slightly longer than temples; sides of forehead slightly emarginate to anterior angles of clypeus; anterior edge of clypeus even; setiferous punctation fine and dense; narrow midline impunctate; distance between punctures as wide as to half as wide as diameter of punctures; on supraocular area punctation denser than on front head; netlike microsculpture deep and dense; surface matt.

Antennae only slightly longer than head; second antennomere globular; thicker than following 3 antennomeres; conical third antennomere shorter than second; fourth to sixth antennomere only slightly wider than third, but wider than long; following 5 antennomeres much thicker than preceding antennomeres and distinctly wider than long; penultimate antennomere 1.5 times wider than long.

Pronotum: 0.60 mm long, 0.67 mm wide; widest at obtuse anterior angles and evenly narrowed to posterior angles; slightly in front of widely rounded posterior angles stronger narrowed; lateral margin moderately thick; in dorsal aspect, near anterior angles not visible; setiferous punctation deep and dense; interstices between punctures not wider than one-fourth of diameter of punctures; row of punctures adjacent to impunctate midline still denser; partly forming short furrow; between large punctures with dense micro-punctation; microsculpture irregularly dense and deep; near anterior margin and along midline with deeper and denser microsculpture; surface matt; on disc large areas without microsculpture; surface polished and shiny.

Elytra: 0.81 mm long, 0.70 mm wide; ground-sculpture deep and coriaceous; punctation in irregular rows; hardly visible in ground-sculpture.

Abdomen with dense and large setiferous punctation; distance between punctures less wide than half of diameter of punctures; irregular microsculpture weak; surface slightly shiny.

Protibia: 0.41 mm long, 0.12 mm wide; semi-circular; with 8 spines at outer edge; WLR: 3.0; in posterior aspect, comb at inner emargination totally visible; posterior face with moderately dense setation.

Aedeagus with triangular apical lobe ending in obtuse apex; at inner edge of apical lobe 2 sensillae with short setae.

Etymology: The specific name is a combination of the epithet grosso meaning thick and punctatus meaning punctate and refers to the thick punctation of the pronotum.

Figures

Fig. 53-57: Osoriellus-s. str.-group: Osoriellus brevicornis (53), O. micros (54), O. surinamensis (55), O. grossopunctatus (55); Osoriellus ashei (57); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.