Osoriellus anceps, 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 : 249

Osoriellus anceps n. sp.

( Figs 29A, C , 31B )

Type material: Holotype, male: Peru: Madre de Dios, Pantiacolla Lodge , 4-7 km NW, El Mirador Trail , 500-800 m elevation, Alto Madre de Dios River (12°39.10'S, 71°15.28'W), collected on logs, 23.10.2000, leg. R. Brooks, #PERU1800 080 ( KNHM).

Diagnosis: The species can be easily identified by the specific structure of the clypeus. According to the deep emargination of the clypeus, it resembles O. cornifrons , but the broad triangular prominences are only present in O. anceps .

Description: Length: 9.5 mm. Colouration: Black; legs and antennae dark brown.

Head: 1.35 mm long, 1.86 mm wide; eyes slightly prominent and slightly longer than temples; sides of fore-head deeply emarginate; sides of clypeus parallel; anterior angles of clypeus produced to broad triangles; between triangles with deep semicircular emargination; mandibles elongate and prominent; setiferous punctation deep; impunctate areas at base of antennae and on midline of vertex; interstices between punctures as wide as or slightly shorter than diameter of punctures; netlike microsculpture deep; surface matt.

Antennae as long as head; second antennomere oval; third conical and slightly shorter than second; fourth antennomere slightly longer than wide; following antennomeres approximately quadrate and and slightly increasing in width.

Pronotum: 1.81 mm long, 1.91 mm wide; widest at obtuse anterior angles; slightly narrowed in anterior half; more distinctly narrowed in posterior half; lateral margin finer in anterior half than in posterior half; setiferous punctation deep, but distinctly sparser than on head; moderately wide midline impunctate; interstices between punctures irregular; ranging from as wide as to twice as wide as diameter of punctures; in posterior half small areas impunctate; netlike microsculpture weaker than on head and surface shinier.

Elytra: 2.09 mm long, 2.00 mm wide; with coriaceous ground-sculpture; setiferous punctation in irregular rows; punctures hardly visible in ground-sculpture.

Abdomen with dense setiferous punctation; punctation still denser than on head; netlike microsculpture deep and dense; surface matt.

Protibia: 1.09 mm long, 0.38 mm wide; thick and nearly semicircular; 9 spines at outer edge; apical spines inserted on extremely short digits; WLR: 3.0; in posterior aspect, comb of inner emargination shortly covered in middle; posterior face with dense yellow setation; on average, setae slightly longer than half of protibial width.

Aedeagus broad and thick; rectangularly angulate; apical lobe slightly sinuate; ending in thick obtuse apex.

Etymology: The specific name derived from the same Latin word meaning on both sides and refers to the two prominent triangles on both sides of the clypeus.

Figures

Fig. 28-30: Osoriellus-granarius-group: Osoriellus granarius (28), O. anceps (29), O. cornifrons (30); antenna (A), protibia (B), aedeagus in ventral and lateral aspect (C); scale bar: 0.1 mm.

Fig. 31: Osoriellus-granarius-group: Head, pronotum and elytra of Osoriellus granarius (A), O. anceps (B), O. cornifrons (C); scale bar: 0.5 mm.