Osoriellus obtusicollis, 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 : 280-281

Osoriellus obtusicollis n. sp.

( Figs 65 A-C, 96C)

Type material: Holotype, male: Guatemala: San José , 22.1.1930, leg. R.E. Blackwelder ( AMNH).

Paratypes: Cuba: Prov. Havana, Cotorro (82°13'W, 23°01'N), luz, female, 9.1998, leg. A. Lozada ( IES) ; Peru: Junin, Satipo (74°38.20'W, 11°15.25S), Puerto Miranda, male, 23.01.1984, L. Huggert ( SMNH) .

Diagnosis: Among the similarly sized species, O. obtusicollis can be identified by the weak microsculpture and the specific shape of the pronotum. Compared to O. flaveolus , the pronotal punctation is coarser and denser and the lateral margin finer, in particular, near the posterior angles. In O. salvini , the pronotal microsculpture is still weaker, the surface nearly polished and the shape of the pronotum is more trapezoidal. Furthermore, the clypeus of O. salvini has short granulate angles, whereas in O. obtusicollis clypeal granules are totally absent.

Description: Length: 3.5 mm. Colouration: Brown; pronotum lighter brown; elytra red; legs and antennae yellow.

Head: 0.50 mm long, 0.69 mm wide; eyes not prominent; as long as temples; sides of fore-head concavely convergent to anterior angles; anterior edge of clypeus even without lateral granules; setiferous punctation coarse; midline on fore-head and small area at base of antennae impunctate; on vertex punctation dense; on average, interstices between punctures half as wide as diameter of punctures; netlike microsculpture weak; surface slightly shiny.

Antennae slightly shorter than head and half of pronotum combined; second antennomere oval and distinctly longer than conical third; antennomeres 4 to 6 as wide as third, but shorter; antennomeres 4 and 5 approximately quadrate; antennomere 6 1.5 times as wide as long; antennomeres 7 to 10 much wider than preceding antennomeres and slightly wider than long.

Pronotum: 0.71 mm long, 0.72 mm wide; widest at anterior angles; anterior angles obtuse and smoothly rounded; sides slightly narrowed to posterior angles; in posterior half more strongly convergent than in anterior half; posterior angles obtusely rounded; lateral margin fine; in dorsal aspect visible throughout its total length except in small part close to anterior angles; irregularly dense setiferous punctation coarse; in irregular rows; interstices between punctures rangeing between half as wide to twice as wide as diameter of punctures; between coarse punctation with sparse micro-punctation; netlike microsculpture weak; surface slightly shiny.

Elytra: 0.82 mm long, 0.75 mm wide; with dense rows of setiferous punctures on coriaceous ground-sculpture; surface matter than on head and pronotum.

Abdomen with dense and coarse setiferous punctation except narrow impunctate midline; weak netlike microsculpture; surface slightly shiny.

Protibia: 0.44 mm long, 0.16 mm wide; thick and wide; 11 spines at outer edge; WLR: 3.30; in posterior aspect, comb at inner edge not visible in small central part; posterior face densely covered by yellow setae.

Aedeagus with short apical lobe ending in widely obtuse apex; five sensillae at inner edge of apical lobe.

Etymology: The specific name is a combination of the Latin words obtusus meaning obtuse and collis meaning pronotum and refers to the smoothly rounded shape of the pronotum.

Figures

Fig. 63-67: Osoriellus-s. str.-group:Osoriellus humicola(63), O. parumpunctatus (64),O. obtusicollis (65),O. tuxtlae(66),O. asperatus (67); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.