3.2.2. Amplissimum group Diagnosis. Aedeagus very wide and short, with elongate median lobe and somewhat truncate (Fig. 27) or incised (Fig. 30) apex; parameres wide, slighty or significantly (Fig. 27) longer than apex of the median lobe. Species included: O. amplissimum sp. n., O. bilobum sp. n. Remarks. Regarding the general shape and ground sculpture of the body, species of the Amplissimum group are similar to the Himalayan species of the Oxyacanthae and the Rivulare group, but differs by shapes of the wide aedeagus and apical portion of the median lobe. 3.2.2.1. Key to Amplissimum group 1 Pronotum widest in apical third, with apical angles not protruded anteriad. Punctation and microsculpture of head and pronotum distinctly coarse. Elytra about as long as broad. Median lobe with truncate apex; parameres very wide, significantly longer than apex of median lobe (Fig. 27). Female accessory sclerite as in Fig. 11. Habitus as in Fig. 24. Body length: 2.70–3.50 mm ...................................................................................... O. amplissimum sp. n. - Pronotum widest slightly above middle, with anterior angles slightly protruded anteriad. Punctation and microsculpture of head and pronotum moderately fine. Elytra slightly broader than long. Median lobe with wide apical excision; parameres moderately wide, slightly longer than apex of median lobe (Fig. 30). Female accessory sclerite as in Fig. 12. Habitus as in Fig. 25. Body length: 2.80–2.97 mm ..................................................................... O. bilobum sp. n.

Published as part of Shavrin, Alexey V., 2023, A revision of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae) of the Himalayan region, pp. 151-206 in Zootaxa 5369 (2) on page 161, DOI: 10.11646/zootaxa.5369.2.1, http://zenodo.org/record/10146170