Osoriellus crassus ( SHARP, 1887 ) 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 : 264

Osoriellus crassus ( SHARP, 1887) new combination

( Figs 78 A-C, 102A)

Osorius crassus SHARP, 1887: 681

Type material examined: Guatemala: San Geronimo , Vera Paz, 1 female, leg. Champion (holotype in BMNH) ; Mexico: Corodva , 2 males, leg. Höge (syntypes in BMNH) .

Diagnosis: O. crassus is one of the largest species of the genus. Only O. sexpunctatus from the remaining-speciesgroup is of similar size, but can be easíly differentiated by the long digitate protibia. Compared to O. sexpunctatus , the microsculpture of the head is deeper and the punctation of the pronotum denser. It also resembles O. parcus , but O. parcus is slightly smaller and has a weaker microsculpture on the pronotum.

Description: Length: 7.8 mm; Colouration: Black, legs and antennae brown.

Head: 1.00 mm long, 1.60 mm wide; eyes short and not prominent; temples 1.5 times as long as eyes; sides of fore-head smoothly sinuate to clypeal angles; front edge of clypeus on each side with two distinct granules; between granules smoothly emarginate; setiferous punctation large and dense; on average, interstices between punctures half as wide as diameter of punctures; wide longitudinal area at base of antennae without punctures; irregular midline also impunctate; supraocular punctures granulate and partly with longer setae; on clypeus and close to neck with pair of two longer setae; isodiametric microsculpture deep; surface slightly shiny.

Antennae with oblong second antennomere; nearly twice as long as wide; third antennomere conical and as long as second; antennomeres 4 and 5 quadrate and not wider than preceding antennomeres; following antennomeres distinctly wider; approximately quadrate.

Pronotum: 1.50 mm long, 1.52 mm wide; widest at anterior angles; anterior angles slightly produced to acute teeth; evenly convergent to obtusely rounded posterior angles; lateral and posterior margin fine; setiferous punctures large, but moderately dense; on average, interstices between punctures as wide as diameter of punctures; irregular row of 14 to 15 punctures adjacent to impunctate midline; netlike microsculpture extremely fine, surface nearly polished.

Elytra: 1.70 mm long, 1.80 mm wide; punctation as deep and dense as on pronotum; punctures in irregular rows of approximately 10 punctures per row; with distinct coriaceous ground-sculpture; surface matter than on pronotum, but slightly shiny than on head.

Abdomen with deep and dense setiferous punctures; punctation still denser than on head; with weak netlike microsculpture; surface slightly shiny.

Protibia 0.82 mm long, 0.32 mm wide; with 13 spines on outer edge; apical spines inserting on short digits; WLR: 1.33; in posterior aspect, comb at inner emargination partly covered in middle; posterior face densely covered by yellow setae.

Aedeagus with apical lobe rounded in smooth curve ending in obtuse apex; left side of apical lobe with numerous sensillae near inner edge; two sensillae near outer edge and another area of sensillae near apex.

Figures

Fig. 73-78: Osoriellus-s. str.-group: Osoriellus frater (73), O. latipes (74); O. mexicanus (75), O. brevipennis (76), O. argentinus (77), O. crassus (78); antenna (A), protibia (B), aedeagus in lateral aspect (C); scale bar: 0.1 mm.