Quediellus Casey, 1915, stat. res.

Brunke, Adam J., 2022, A world generic revision of Quediini (Coleoptera, Staphylinidae, Staphylininae), part 1. Early diverging Nearctic lineages, ZooKeys 1134, pp. 129-170 : 129

publication ID	https://dx.doi.org/10.3897/zookeys.1134.87853
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scientific name	Quediellus Casey, 1915, stat. res.
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Treatment

Figs 5C, D View Figure 5 , 8K-Q View Figure 8 , 9H, I View Figure 9

Quediellus Casey, 1915: 398, 402; Smetana 1971 (as synonym of Quedius (Raphirus) ), Brunke et al. 2021 (phylogeny, isolated position, non- Raphirus , to be reinstated as genus).

Type species.

Quedius debilis Horn, 1878.

Diagnosis.

Quediellus , in the restricted sense used here, can be recognized within Quediini by a combination of: head with genal and interocular punctures absent; pronotum without extra punctures between dorsal and sublateral rows, sublateral rows not extended posteriad of single large lateral puncture (but sometimes at same level); prosternum without trace of longitudinal carina; scutellum impunctate; elytra with punctures not arranged in distinct rows, spaces between with distinct meshed microsculpture (Fig. 5D View Figure 5 ). Quediellus and Quedionuchus are the only genera of Quediini with meshed (scale-like) microsculpture on the elytra (Fig. 5D, E View Figure 5 ), while other lineages may have granulose microsculpture composed of micropunctures or microsetae (Fig. 5F View Figure 5 ), superficially giving a similar dull appearance at low magnification. Quediellus differs from Quedionuchus by the irregularly scattered (not rows) or evenly distributed elytral punctures (Fig. 5D View Figure 5 versus Fig. 5E View Figure 5 ) and complete infraorbital ridge, running from the neck to the base of the mandibles under the eye.

Quediellus shares plesiomorphic, simple head chaetotaxy (though the basal puncture is often doubled, e.g., Fig. 5C View Figure 5 ) with members of the mostly Palaearctic subgenus Quedius (Raphirus) (sensu Brunke et al. 2021), with which it was long considered to be synonymous. However, all Quedius (Raphirus) differ by the lack of meshed microsculpture on the elytra and those with a dull reflection between the punctures (e.g., Q. cincticollis Kraatz, Q. fumatus (Stephens), the members of clade ‘X2’ of Brunke et al. 2021 ( Q. lateralis (Gravenhorst) and its relatives)) have micropunctures rather than meshes, much denser elytral punctation and most have an, at least partly, carinate prosternum.

Redescription.

Small and slender, to medium-sized and fusiform rove beetles, often with pale yellow markings on apex, humerus and sides of elytra (Fig. 12 View Figure 12 ). With the character states of Quediini (see Brunke et al. 2021) and the following: antennomere 3 longer than 2, without dense setae; head with eyes large, much more than twice as long as temples, convex, bulging from lateral head outline, weakly convergent anteriad and with inner margin well separated from suprantennal ridge (Fig. 5C View Figure 5 ); antennal insertions close to inner margin of eye, separated by about the width of antennal sclerite (Fig. 5C View Figure 5 ); frons weakly developed anterolaterad of antennal insertions; with single or doubled basal puncture; interocular, parocular and genal punctures absent; labrum notched medially, creating two short lobes; apical maxillary and labial palpi fusiform and glabrous; infraorbital ridge complete to mandibles; gular sutures converging towards neck and narrowly spaced posteriad; mandibles with dorsal lateral groove; right mandible with single, simple tooth (Fig. 5C View Figure 5 ); pronotum subquadrate; hypomeron strongly inflexed, not visible in lateral view; with single large lateral puncture; dorsal row of pronotum with three punctures; sublateral row not reaching level of large lateral puncture; basisternum with pair of distinct macrosetae, without trace of longitudinal carina; elytron with subbasal ridge complete, forming scutellar collar; scutellum impunctate; with row of three or four humeral spines; disc of elytra with even punctation, with distinct meshed microsculpture; foretibia with lateral spines and apical spurs; metatarsomeres with disc setose; metatibia spinose with at least three spines on outer face; abdominal tergite I with prototergal glands well developed, with one side surrounded by row of well-developed setae; abdominal tergites without impressed, glabrous basal areas; abdominal sternite III with basal transverse carina forming obtuse angle at middle, not produced; abdominal sternite VII unmodified; abdominal sternite VIII with distinct median emargination; aedeagus with well-developed paramere bearing peg setae (Fig. 8M, N View Figure 8 ).

Distribution.

Quediellus is endemic to the western Nearctic, occurring along the western cordilleras from southern British Columbia to southern California on the western side of the continental divide, and known from the Rocky Mountains of Alberta, Idaho and Montana on the eastern side.

Bionomics.

Specimens have been collected mainly from sifting leaf litter, rotting wood and moss along streams, in forests and in montane meadow.

Comments.

Casey (1915) erected the genus Quediellus to unite species belonging to the Debilis and Brunnipennis groups of Smetana (1971), based on an entire labrum. This concept was correctly recognized by Smetana (1971) as erroneous as not only did he consider these two groups to be distantly related but only Quedius densiventris exhibited an entire labrum and only in some individuals. The always bilobed labrum of Quediellus is quite transverse in some specimens and sometimes at lower magnification it can be difficult to observe its shape. The type species of Quediellus , Q. debilis , was assigned to the Debilis group of Quedius (Raphirus) by Smetana (1971) and has been treated as such ever since. Quite recently ( Brunke et al. 2021), the Debilis group (as Quedius nanulus (Casey)) was shown to be one of the smaller, phylogenetically isolated lineages of Quediini and quite distantly related to true Quedius (Raphirus) , despite sharing several morphological, though plesiomorphic, character states including the simple head chaetotaxy. In order to achieve monophyly of both Quedius and subgenus Quedius Raphirus , Quediellus is here resurrected as a valid genus under a morphological concept that is similar to that given by Smetana (1971) for the Debilis group.