Stenichnus Thomson

Jałoszyński, Paweł, 2013, Revision of subgenera of Stenichnus Thomson, with review of Australo-Pacific species (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 3630 (1), pp. 39-79 : 40-41

Genus Stenichnus Thomson

Stenichnus Thomson, 1859: 61 . Type species: Scydmaenus exilis Erichson, 1837 (original designation).

Stenichnus comprises species that share the following diagnostic set of characters: eyes located posteriorly; occipital constriction only slightly narrower than vertex; fronto-clypeal groove present; mandibles falciform, without setose prostheca and without mesal teeth but with row of fine denticles along mesal margin; prementum with two labial discs and broadly separated bases of labial palps; submentum trapezoidal, completely demarcated from hypostomae by lateral sutures; hypostomae elongate and demarcated from genae by complete hypostomal ridges; posterior tentorial pits hidden in deep groove separating submentum from gular plate; antennae gradually thickening distally; pronotum approximately pentagonal, with ante-basal pits or a row of punctures, without lateral marginal carinae or edges; prosternum with narrow basisternal part demarcated from procoxal cavities by carina, procoxal cavities separated in middle by fine prosternal intercoxal carina; hypomera not demarcated from pronotum; mesoventrite with asetose and setose lateral impressions; mesocoxal projections with posterior lobes; mesoventral intercoxal process narrow and moderately strongly projecting ventrally, with distinct posterior tip separated from metaventrite; metaventrite with distinct metaventral anterior process and short and broad metaventral intercoxal process bearing median notch; aedeagus with free parameres.

In order to compare character states in all taxa hitherto regarded as subgenera of Stenichnus the morphology of Stenichnus s. str. was studied in detail. The description of morphology given below is based on Stenichnus (s. str.) collaris , a common and abundant Central European species, which was selected because of several reasons: i) it is similar to S. bicolor (Denny, 1825) (= exilis Erichson ), the type species of Stenichnus ; ii) it is the type species of Cyrtoscydmus Motschulsky, 1870 , a junior synonym of Stenichnus s. str.; iii) adequate number of specimens was available for disarticulations. Additional remarks or examples are given based on many other species of Stenichnus s. str. studied previously (e.g., Jałoszyński 2004, 2006, 2009).