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.

Published as part of Irmler, Ulrich, 2014, The Neotropical species of the genus Osoriellus FAGEL, 1959 (Coleoptera: Staphylinidae: Osoriinae), pp. 231-354 in Beiträge Zur Entomologie = Contributions to Entomology 64 (2) on page 264, DOI: 10.21248/contrib.entomol.64.2.231-354, http://zenodo.org/record/5461706