Euconnus imparitus Zi-Wei Yin, Ting Feng & De-Yao Zhou 2025, sp. nov.
Creators: name: Yin, Zi-Wei
name: Feng, Ting
name: Zhou, De-Yao
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Euconnus
Euconnus imparitus

description: Euconnus (s. str.) imparitus Zi-Wei Yin, Ting Feng & De-Yao Zhou sp. nov.
Figs 2, 4
Type material
(1 ex.). Holotype: China: • ♂: ‘ China: Shanghai, Jiading, Waigang To., Quanjing Vill., 31°22'29"N, 121°8'22"E, late vii. 2018, light trap, D-Y Zhou leg., 嘉定外冈泉泾村测报灯周德尧’ (SNUC).
Diagnosis.
Male. Habitus elongate; body length approximately 1.7 mm. Head and elytra finely punctate, subglabrous, with sparse long setae; punctation and setae of pronotal disc similar to those of head and elytra, lateral margins densely setose and with numerous thick bristles. Head subspherical, eyes anteriorly situated, tempora much longer than eyes. Antennae elongate, antennomeres elongate, clubs loosely formed by apical four enlarged antennomeres. Pronotum lacking antebasal pits, transverse impression, or sublateral carinae; broadest slightly posterior to middle. Tarsomere 1 of protarsus modified, ventrally protruding to form apically truncate projection. Aedeagus moderately elongate, dorso-ventrally symmetric; compressor plate in ventral view with two lateral lobes; apical projection of median lobe broad at base and narrowing apically; parameres broadened before apices, each paramere with three macrosetae at apex. Female. Unknown.
Description.
Male. Body (Fig. 2 A) length 1.66 mm; body uniformly reddish-brown, mouthparts and tarsi paler in color. Setae long and suberect, sparse on head and pronotal and elytral discs, sides of pronotum with dense, thick bristles. Dorsum of body finely and sparsely punctate, almost glabrous.
Head subrounded, as long as wide, broadest at eyes, length and width 0.36 mm; vertex and frons confluent, weakly convex; supraantennal tubercles barely prominent; eyes relatively small, barely convex and finely faceted. Punctures on vertex and frons fine; setae long and sparse, suberect, tempora much longer than eyes, lacking bristles. Antenna elongate, length 0.93 mm, club 0.48 mm; antennomeres 1–7 each elongate, 2 and 7 longest, 8–11 broader than 2–7, enlarged, form loose club.
Pronotum in dorsal view slightly longer than wide, subglobose, broadest slightly posterior to middle and narrowing anteriorly and posteriorly, length 0.4 width 0.41 mm; lacking lateral antebasal pits, transverse antebasal groove and sublateral carinae. Punctures on pronotal disc rather fine, almost glabrous; setae sparse and long, laterally obscured by dense, long and thick bristles.
Elytra suboval and slightly flattened, broadest approximately at middle, length 0.94 mm, width 0.73 mm, length / width 1.29; basal impressions shallow, with four small, asetose basal pits, humeral calli weak; apices of elytra separately rounded. Punctures on elytral disc fine and shallow; sparse setae long and suberect. Metathoracic wings fully developed, functional.
Meso- and metaventrite fused. Mesoventral intercoxal process posteriorly extending far beyond level of posterior margin of mesocoxae. Metaventral intercoxal process broad, emarginate at middle.
Legs long and slender; protarsus with tarsomere 1 projecting ventrally, forming short, apically truncate lobe (Fig. 2 B).
Aedeagus (Fig. 2 C – F) moderately elongate, dorso-ventrally almost symmetric, length 0.34 mm, in ventral view median lobe with long, apically narrowing projection greatly curved dorsally, with two rows of fine setae along dorsal wall of projection; compressor plate broadened in dorso-ventral view, with pair of short and broad lateral lobes, plate inclined to apically-projected median lobe in lateral view and curved dorsally; endophallus armature composed of pairs of elongate and sclerotized plates and membranous structures; parameres elongate, narrow, extending just beyond base of apical projection of median lobe, areas before apices greatly broadened and then abruptly narrowing apically, each paramere with three long macrosetae at apex.
Female. Unknown.
Comparative notes.
This species is closely related to Euconnus impar Sharp, distributed in Japan and South Korea, due to similar morphological features (elongate habitus, subglabrous head and elytra, dense bristles on pronotum sides, loosely assembled tetramerous antennal clubs), and particularly the modified male protarsi. However, E. imparitus is clearly distinguishable by its significantly different aedeagal structure. The aedeagus of the new species comprises a compressor plate with two short, blunt lateral lobes (vs. with two long, rod-like lobes in E. impar), a dorso-apical projection of the median lobe that narrows apically in ventral view (vs. apical projection broad and blunt in E. impar), and parameres broadening near the apices, each bearing three apical macrosetae (vs. parameres slender throughout, each with two long apical setae in E. impar). Additionally, the apical four antennomeres forming the club of this species appear relatively more elongate than those of E. impar.
Distribution.
East China: Shanghai (Jiading) (Fig. 4 A).
Biology.
The male was taken from a mixed light trap sample deployed in an agricultural setting (Fig. 4 E).
Etymology.
The specific epithet is derived from a combination of E. impar, a closely related species, and the Latin suffix “ - itus (- a, - um) ”, denoting an affinity between these two species.
description: Published as part of Yin, Zi-Wei, Feng, Ting & Zhou, De-Yao, 2025, First report of subfamily Scydmaeninae (Coleoptera, Staphylinidae) from Shanghai, with description of two new species, pp. 133-143 in ZooKeys 1231 on pages 133-143, DOI: 10.3897/zookeys.1231.142538