Pseudodialycera Zanetti & Shavrin, 2020

Shavrin, Alexey V. & Zanetti, Adriano, 2020, Revision of Acrulia Thomson, 1858 and Dialycera Ganglbauer, 1895, with taxonomic notes on related genera and description of a new genus from the Caucasus (Coleoptera: Staphylinidae: Omaliinae: Omaliini), Zootaxa 4800 (1), pp. 1-63 : 44-45

3.5. Pseudodialycera Zanetti & Shavrin , gen. nov.

Type species: Omalium striatipenne Aubé, 1850 .

Description. Body glossy, narrow, and parallel-sided, with flattened forebody, Dropephylla -shaped. Punctation of forebody moderately dense and coarse; punctation coarser and deeper on elytra, with punctures arranged in longitudinal striae. Pubescence very short, except for some long setae on pronotum and elytra. Surface of forebody without microsculpture. Length 2.30–2.60 mm.

Head distinctly narrower than pronotum, distinctly broader than long; vertex slightly elevated between two short supraocular furrows, scarcely convergent posteriorly; portions between supraocular furrows and eyes with longitudinal wrinkles; eyes normally developed, moderately large, much longer than short and angular temples, with distinct postocular carina; posterior constriction marked with distinct narrow furrow. Ocelli moderately distinct, with short anteocellar pits. Anterior margin of labrum slightly emarginate. Mandibles abruptly curved and acute at apex. Maxillary palpi with apical segment long, clearly narrower and slightly shorter than the somewhat dilated preapical palpomere (Fig. 16). Basal segment of labial palpi short and wide, segment 2 narrower, as wide as long, segment 3 narrower than preceding segment, as long as wide, apical segment narrow and elongate. Gular sutures moderately narrowly separated from each other at level of anterior portions of eyes and significantly divergent porteriorly. Antenna slightly exceeding than combined length of head and pronotum when reclined; antennomere 6 not narrower than 5 and 7, apical five antennomeres forming a loose club, with moderately short setation, and antennomeres 7–10 distinctly transverse.

Pronotum slightly transverse, with irregularly crenulate lateral margins. Prosternum with moderately long intercoxal process reaching middle of coxae, with distinct median longitudinal carina. Mesoventrite short, with partial median carina; intercoxal process acute. Scutellum large and triangular. Metaventrite moderately broad, convex, with short angular intercoxal process.

Elytra short, extending to anterior margin of abdominal tergite III, with distinctly crenulate lateral margins and broad epipleura. Wings fully developed.

Legs moderately short; procoxae transverse with prominent distal portion; mesocoxae oval; metacoxae large and subtriangular; tibiae distinctly widened apicad; tarsi short and narrow, tarsomere 5 distinctly longer than the combined length of the remaining four tarsomeres.

Abdomen convex, long, slightly narrower than elytra, with a pair of small wing-folding patches in middle of tergite IV.

Male. Medioapical surface of apical abdominal sternites without modifications.Aedeagus of the basic omaliinae type (Figs. 59–60), with moderately wide basal portion and median lobe, encased by a single sclerotized piece, with only ventral median line unsclerotized, with moderately thick and short cylindrical parameres bearing modified setiferous surface in distal parts, with apical setae 2+2.

Female. Apical abdominal sternites without modifications. Genital segment (Fig. 68) with apical lobes of gonocoxites long and narrow, with thin and short styli; accessory abdominal sclerite moderately wide and long, forming median piece divided into two elongate branches, with paired sclerotized apical structures. Spermatheca not found.

Immature stages. Unknown.

Species included. Pseudodialycera striatipennis ( Aubé, 1850) .

Differential diagnosis. The type species was originally included in Dialycera , but it lacks most of the main characters of this genus (maxillary palpi with apical segment conical, slightly longer than the penultimate segment (Fig. 16), antennomere 6 slightly narrower than 5 and 7, male abdominal sternite VII unmodified, median lobe with ventral surface without narrow appendage (Fig. 59), with wide apical portion and cylindrical parameres somewhat similar to those of Acrulia (Figs. 33, 35, 37), female genital segment with elongate gonocoxites and short styli (Fig. 68). It shares with Dialycera only the the crenulate lateral margins of the pronotum.

Pseudodialycera , a new monotypical genus of the subfamily Omaliinae , belongs to the group of genera of Omaliini without elliptical plate on the ventral surface of the aedeagus (see above). Based on the general shape of the forebody, it resembles species of the genus Dropephylla Mulsant & Rey, 1880 , but the maxillary palpi of Pseudodialycera (Fig. 16) have a long and narrow apical segment similar to that in Phloeonomus Heer, 1839 and allied genera ( Phloeostiba Thomson, 1858 , Paraphloeostiba Steel, 1960 and Xylostiba Ganglbauer, 1895 ). Besides, the aedeagus of all these genera has an elliptical plate on its ventral surface. In addition to the conspicuous differences of the aedeagus (see Zanetti 2012), Pseudodialycera can be distinguished from these genera by the following morphological features: from Phloeonomus , Paraphloeostiba and Phloeostiba primarily by the glossy surface of the pronotum and elytra, without miscrosculpture, and from Xylostiba by the shorter setation of the antenna. Pseudodialycera is best identified based on the small, parallel-sided and rather flattened body, crenulate lateral margins of the pronotum, and the long apical segment of the maxillary palpi being distinctly narrower than the penultimate segment.

Natural history. All specimens were sifted from forest litter (see details below).

Distribution. Caucasus: Georgia (Fig. 74).

Etymology. The feminine generic name is a combinations of Greek adjective ψευδο (false) and the existing name Dialycera , the genus in which the type species had been originally included.