Anthobium algidum, Erichson, 1840

Shavrin, Alexey V., 2022, A revision of Palaearctic Anthobium Leach, 1819 (Coleoptera: Staphylinidae Omaliinae: Anthophagini). V. Algidum, morosum and tectum groups, a new species of the fusculum group, and faunistic records, Zootaxa 5104 (3), pp. 301-346 : 304

Algidum group

Diagnosis. Body moderately narrowly elongate; maxillary palpomere long, with elongate maxillary palpomere 2, about as long as apical palpomere; anterior portion of head between antennal insertion and anterior margin of eye moderately long, with distinct semicircular notch; pronotum with or without mediobasal impression; middle surface of each elytron with or without indistinct irregular elevations between punctures; meso- and metatibiae covered by dense and stout spines; apex of median lobe wide and deeply sinuate.

Species included. Anthobium algidum ( Erichson, 1840) .

Remarks. Regarding the general shape of the body and long elytra with indistinct irregular elevations between punctures in middle portions of each elytron, A. algidum is similar to some species (e.g. A. daliense Shavrin & Smetana, 2017 ) of the gracilipalpe group ( Shavrin & Smetana 2017), from which it differs by the presence of a distinct notch between the antennal insertion and the anterior margin of the eye, the absence of fine crenulation on the lateral edges of the pronotum and the latero-apical margins of elytra, the absence of longitudinal elevations in the median portion of the elytra, and stouter setation of meso- and metatibia. Based on the presence of a similar notch in the latero-apical portions of the head, the absence of the crenulation on the lateral edges of the pronotum and elytra, and similar features of the setation of meso- and metatibia, it is similar to species of the tectum group, from which it can be distinguished by a larger and more elongate body, the shape of the apical portion of the head (more protruding apicad), and a less transverse pronotum, which is more narrowed posteriad than anteriad. From both groups, it differs by narrower apical portions of the mandibles, a narrower maxilla with markedly longer maxillary palpomeres 2, and a different morphology of the aedeagus, with a wide and deeply sinuate apical margin of the median lobe.

The shape of the median lobe (deeply sinuate apical margin) is similar to that in species of other genera of the Anthobium group: western Palaearctic Deliphrosoma Reitter, 1909 ( Zerche 1991) and some species of the genus Arpedium Erichson, 1839 (e.g. Nearctic A. schwarzi Fauvel, 1878 , see Campbell (1984)).