Quedius Stephens, 1829

Salnitska, Maria & Solodovnikov, Alexey, 2018, Revision of the Quedius fauna of Middle Asia (Coleoptera, Staphylinidae, Staphylininae), Deutsche Entomologische Zeitschrift 65 (2), pp. 117-159 : 118-119

Genus Quedius Stephens, 1829

Type species.

Quedius levicollis ( Brullé, 1832).

According to the latest phylogenetic hypotheses (Solodovnikov, 2006; Chatzimanolis et al., 2010; Brunke et al., 2016) the genus Quedius as it stands now in the taxonomic literature (e.g., summaries in Herman, 2001 or Schülke and Smetana, 2015) is a polyphyletic assemblage of species belonging to several different subtribes of Staphylinini . Within the Palaearctic or Middle Asia, all species of Quedius are members of the subtribe Quediina in the restricted sense of Brunke et al. (2016). Because of the polyphyly, Quedius in the current composition lacks synapomorphies and clear diagnosis. However, genus descriptions and diagnostic combination of characters that can define any Palaearctic species as a member of the genus Quedius are available in Coiffait (1978), Smetana (1988), Assing and Schülke (2012) and other sources. The diagnosis of the genus Quedius and comparative notes we provide here are tuned for the fauna of Middle Asia.

Adults and larvae of Quedius seem to be predators hunting small invertebrates in various, sufficiently hu mid ground-based debris, mostly in forest leaf litter. In a largely arid region like Middle Asia, Quedius are mainly confined to humid open or forested habitats along creeks or rivers in the lowland or forests, meadows, snowfield margins and talus in the mountains. Some members of the subgenus Microsaurus are specialized inhabitants of mammal burrows. Overall, bionomics of the genus in Middle Asia remain largely unstudied.

Diagnosis.

Medium to large size (body length 3.5-24.0 mm) rove beetles with glossy forebody, infraorbital ridges extended from neck to base of mandibles and pronotal hypomera strongly inflexed under pronotal disk (not visible in lateral view). First segment of antennae at most slightly longer than second and third segments together. Last segment of maxillary palps fusiform, not densely setose. Tarsal formula 5 –5– 5; anterior tarsi widened in both sexes, with pale adhesive setae ventrally, with pair of empodial setae. Males always with distinct apical emargination on abdominal sternite VIII. Aedeagus varies in shape, paramere mostly with sensory peg setae.

Comparison.

Among other Staphylinini in Middle Asia Quedius can be sometimes confused with Philonthus (subtribe Philonthina), a genus with somewhat similar habitus and very abundant in the region. Species of Philonthus , however, do not have long infraorbital ridges, they lack empodial setae and mostly have a pronotal hypomeron well visible in lateral view. Also, Philonthus mostly possess multiple setiferous punctures in dorsal rows of pronotum (usually at most three in Quedius ). Smaller species of Quedius may be confused with the genus Heterothops (subtribe Amblyopinina), but the latter have very thin acicular apical segments of maxillary palps, and a very different aedeagus without sensory peg setae and reduced median lobe giving the appearance of an absent paramere).