Osoriellus minor ( NOTMAN, 1925 ) 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 : 279

Osoriellus minor ( NOTMAN, 1925) new combination ( Figs 69 A-C, 97F)

Osorius minor NOTMAN, 1925: 4

Type material examined: Trinidad: Montserrat , 1 female, 30. June 1905, leg. A. Busck (holotype in NHMW) .

Further material examined: Mexico: Quintana (87°35'W, 19°46'N), 12 km N Reforma, male, 14.10.1986, G. Rozen ( AMNH) .

Diagnosis: Among the similarly sized species of the O.-s. str.-group, O. minor is characterised by the absence of microsculpture on the pronotum and the dense setiferous punctation. In this respect, it resembles O. tuxtlae , but the pronotal sides are curved in O. minor , whereas they are forming a more trapezoidal shape in O. tuxtlae . The aedeagus of O. minor has a smoothly curved short apical lobe; whereas the aedeagus of O. tuxtlae is rectangularly angulate.

Description: Length: 4.8 mm. Colouration: Black; legs and antennae brown; posterior edge of pronotum dark reddish.

Head: 0.61 mm long, 0.94 mm wide; eyes slightly prominent; approximately twice as long as temples; angles of clypeus produced to short granules; setiferous punctation moderately dense and deep; posteriorly and laterally much denser than on clypeus; on clypeus, interstices between punctures at least twice as wide as diameter of punctures; on posterior vertex interstices between punctures shorter than diameter of punctures; supraocular punctures more distinctly granulate than punctures on vertex; few supraocular short striae; isodiametric microsculpture dense and distinct; surface slightly shiny.

Antennae with oval second and conical third antennomere equally long; following three antennomeres quadrate or slightly wider than long; last five antennomeres distinctly thicker than preceding antennomeres, but more or less quadrate.

Pronotum: 0.93 mm long, 1.00 mm wide; widest near anterior angles; evenly convergent to obtuse posterior angles; lateral margin fine; large setiferous punctures in irregular rows; on average, interstices between punctures half as wide as diameter of punctures; narrow midline impunctate; surface with weak netlike microsculpture; microsculpture less deep than on head and surface more shiny.

Elytra: 1.04 mm long, 1.04 mm wide; large setiferous punctures hardly visible between deep coriaceous ground-sculpture; punctures in irregular rows.

Abdomen with dense and deep setiferous punctation; isodiametric microsculpture distinct and similar as on head; microsculpture more distinct than on pronotum.

Protibia: 0.50 mm long, 0.17 mm wide; 8 spines on outer edge; apical spines inserted on short digits; WLR: 2.10; in posterior aspect, comb of inner emargination totally visible; posterior face with dense setation.

Aedeagus slender; apical lobe straight; slightly curved in nearly rectangular angle to acute apex; inner edge of apical lobe with row of several sensillae.

Figures

Fig. 68-72: Osoriellus-s. str.-group: Osoriellus boliviensis (68), O. minor (69), O. rugipennis (70), O. triangulatus (71), O. franckei (72); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.