Osoriellus trapezoides, 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 : 289

Osoriellus trapezoides n. sp.

( Figs 82 A-C, 101A)

Type material: Holotype, male: Costa Rica: Puntarenas Prov., Altamira Biol. Sta. (83°00.49'W, 09°01.76'N), 1510-1600 m elevation, collected by flight intercept trap CR1AFH04144, 4.-7.VI.2004, leg. J.S. Ashe, Z. Falin, I. Hinojosa ( KNHM).

Paratype: Costa Rica: Alajuela, E.B. San Ramon, R.B. San Ramon, 27 km N & 8 km W San Ramon (84°35.30'W, 10°13.30'N), male, collected from wet montane forest litter CR1A99-109D, 29.6. – 6.7.1999, leg. R. Anderson ( UIC) .

Diagnosis: The species is similarly sized as O. debilis , but the shape of the head and pronotum is distinctly different. It can be easily identified by the conspicuous trapezoidal shape of the head.

Description: Length: 5.2 mm. Colouration: Dark brown; elytra reddish brown; legs and antennae lighter brown.

Head: 0.63 mm long, 1.06 mm wide; eyes slightly prominent and slightly longer than temples; sides of fore-head convergent to front angles in slight sinuate curve; close to anterior edge nearly parallel; in dorsal aspect, shape trapezoidal; clypeal angle produced to short granules; anterior edge even; setiferous punctation weak and sparse; near base of antennae impunctate and on supraocular area with denser punctation; on vertex, interstices between punctures wider than diameter of punctures; one supraocular seta and one neck seta longer than normal setation; isodiametric microsculpture extremely weak; surface shiny, nearly polished.

Antennae distinctly longer than head; with oblong second antennomere and conical third antennomere; each longer than wide; following three antennomeres not wider than preceding antennomeres, but approximately quadrate; antennomeres 7 to 11 thicker than preceding antennomeres and also quadrate.

Pronotum: 0.98 mm long, 1.08 mm wide; widest at anterior angles; anterior angles produced to short teeth; sides slightly convergent in anterior two-third; more strongly convergent in posterior third; lateral margin fine; close to anterior angles invisible in dorsal aspect; posterior angles obtuse; smoothly rounded; setiferous punctation deeper and denser than on head; with impunctate midline; 10 punctures in irregular row adjacent to midline; on average, interstices between punctures half as wide as diameter of punctures; few sparser punctate areas in posterior half; between large setiferous punctation with sparse micro-punctation; isodiamteric microsculpture deeper and more distinct than on head; surface shiny, but less shiny than on head.

Elytra: 1.25 mm long, 1.18 mm wide; with coriaceous ground-sculpture; setiferous punctation hardly visible in coarse ground-sculpture; punctures in irregular rows.

Abdomen with setiferous punctation and impunctate midline on tergites II to VII; netlike microsculpture weak; surface shiny.

Protibia: 0.58 mm long, 0.18 mm wide; nearly semicircular; 8 spines on outer edge; WLR: 2.0; in posterior aspect, comb of inner emargination visible throughout its total length; posterior face with moderately dense setation; setae nearly half as long as protibial width.

Aedeagus with smoothly rounded apical lobe ending in obtuse apex.

Etymology: The specific name trapezoides refers to the trapezoidal shape of the head.

Figures

Fig. 79-83: Osoriellus-s. str.-group: Osoriellus debilis (79), O. parcus (80), O. schwarzi (81), O. trapezoides (82), O. opacus (83); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.