Osoriellus opacinotus, 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 : 303-304

Osoriellus opacinotus n. sp.

( Figs 112 A-C, 124E)

Type material: Holotype, male: Panama: Chiriqui Prov., La Fortuna , Cont. Divide Trail (08°46'N, 82°12'W), 1150 m elevation, 23.5.- 9.6.1995, collected by flight intercept trap, #155, leg. J. Ashe & R. Brooks ( KMNH).

Paratypes: Panama: 3 females, 1 male with same data as holotype ( KMNH) ; Chiriqui Prov., NW of Volcán (82°40.26'W, 8°49.16'N), 1400 m elevation, litter near stream, 17.5.2001, leg. L. Herman & W. Opitz ( AMNH) ; Costa Rica: San José Prov. 2.4 km ENE San Gerardo de Rivas, Cloudebridge Reserve, House Environs. (09°28.36'N, 83°34.51'W), 1700 m elevation, male, female, 8.- 11.6.2004, leg. J.S. Ashe, Z. Falin, I. Hinojosa, collected by flight intercept trap ( KMNH) ; Cartago Prov., Ref. Nac. de Fauna Silvestre Tapanti , 2.5 km E Station (9°44.23'N, 83°46.82'N), 1330 m elevation, female, 30.10- 1.11.2001, collected by flight intercept trap, leg. R. Brooks ( UIC) .

Diagnosis: The species shows a high variability concerning the shape and microsculpture of the pronotum. The acute prominent anterior angles range from very short to extremely long. In the last case, the anterior edge of the pronotum seems to be distinctly emarginate. The microsculpture also varies from deep netlike or isodiametric with matt surface to weak netlike with micro-punctation between the normally setiferous punctation and slightly shiny surface. The species resembles O. schwarzi in size and microsculpture of the pronotum, but O. schwarzi shows only a slight variability in the microsculpture and has no digitate protibia. The shape of the pronotum slightly differs from O. schwarzi . In O. opacinotus , the sides are evenly convergent to posterior angles, whereas in O. schwarzi the curve of sides is more convex. In particular, the posterior angles of O. schwarzi are evenly rounded, whereas in O. opacinotus the pronotal shape is trapezoidal.

Description: Length: 6.8 mm. Colouration: Dark brown; elytra brown, legs and antennae lighter brown.

Head: 1.03 mm long, 1.29 mm wide; eyes slightly prominent; as long as temples; sides of fore-head convergent to anterior angles in concave curve; anterior edge of clypeus even with angles produced to short granules; setiferous punctation on vertex weak and sparse; on supraocular area denser; isodiametric microsculpture dense and deep; surface matt.

Antennae long and slender; second and third antennomeres nearly twice as long as wide and nearly twice as long as fourth antennomere; fourth antennomere as wide as preceding antennomeres; following antennomeres increasing in width, but all approximately quadrate.

Pronotum: 1.28 mm long, 1.47 mm wide; widest at anterior angles; evenly convergent to posterior angles; posterior angles rounded; lateral margin fine; in dorsal aspect, visible in its total length; setiferous punctation moderately sparse; punctures slightly larger than on head; wide midline impunctate; interstices between punctures irregular; on average, as wide as diameter of punctures; between irregular rows, interstices between punctures wider than diameter of punctures and few areas impunctate; isodiametric microsculpture dense and deep; surface matt.

Elytra: 1.47 mm long; 1.47 wide; with weak coriaceous ground-sculpture and weak punctation; punctures in irregular rows and only slightly visible in ground-sculpture.

Abdomen with netlike microsculpture and dense setiferous punctation; surface matt.

Protibia: 0.74 mm long, 0.22 mm wide; semicircular; with 10 spines on outer edge; apical spines inserted on long digits; WLR: 0.62; in posterior aspect, inner emargination with comb partly covered; posterior face sparsely covered with yellow setae.

Aedeagus with long slender apical lobe ending in acute apex.

Etymology: The specific name is a combination of the Latin words opacus meaning matt and notum meaning the pronotum and refers to the matt surface of the pronotum.

Figures

Fig. 109-113: Remaining-species-group: Osoriellus cordovensis (109), O. germanus (110), O. notmani (111), O. opacinotus (112), O. sexpunctatus (113); antenna (A), protibia (B), aedeagus in ventral and lateral aspects (C); scale bar: 0.1 mm.