Euconnus (Tetramelus) aurilobatus Jałoszyński, 2024, sp. nov.
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Euconnus
Euconnus aurilobatus

description: Euconnus (Tetramelus) aurilobatus sp. nov.
(Figs 14, 22, 39–68)
Material studied. Holotype: ♂ (CHINA: Gansu): “CHINA: Gansu Prov. [CH 11-27] / Lenglong Ling Mts., 60 km NNW / Honggu, Jin Sha Gorge, mixed forest / (Picea, Populus, Betula), 36°51’56.9’’N, / 102°38’55.3’’E, litter, moss, mushrooms / sifted, 12.VII.2011, leg. M. Schülke” [white, printed], “ EUCONNUS / (TETRAMELUS) /
aurilobatus m. / P. Jałoszyński, 2024 / HOLOTYPUS ” [red, printed] (MNHB). Paratypes (22 exx.): 1 ♂, same data as for holotype; 3 ♂♂, “ CHINA: Gansu Prov. [CH11-27a] / Lenglong Ling Mts., 60 km NNW / Honggu, Jin Sha Gorge, mixed forest / (Picea, Populus, Betula), 36°51’56.9’’N, / 102°38’55.3’’E, litter, moss, mushrooms / sifted, 14/ 15.VII.2011, leg. M. Schülke ” [white, printed]; 5 ♂♂, “ CHINA: Qinghai Prov. [CH11-08] / Daban Shan, 60 km NW Honggu / 36°49’10.7’’N, 102°31’’22.8’’E, 2366- / 2400 m, mixed forest (Betula, Populus, / Picea) dead wood, litter sifted / 25. VI.2011, leg. M. Schülke ” [white, printed]; 2 ♂♂, “ CHINA: Gansu Prov. [CH11-13d] / Lenglong Ling Mts., 80 km NNW / Honggu, 37°03’50.3’’N, 102°39’57.2’’E, / 3392 m, alpine pasture with / Rhododendron, litter, grass roots sifted / 1.VII.2011, leg. M. Schülke ” [white, printed]; 3 ♂♂, 2 ♀♀, “ CHINA: Qinghai Prov. [CH11-08a] / Daban Shan, 60 km NW Honggu / 36°49’10.7’’N, 102°31’’22.8’’E, 2366- / 2400 m, mixed forest (Betula, Populus, / Picea) dead wood, litter sifted / 11.VII.2011, leg. M. Schülke ” [white, printed]; 2 ♂♂, 1 ♀, “ CHINA: Qinghai Prov. [CH11-09] / Daban Shan, 62 km NNW Honggu / creek valley, Picea, Populus, Betula / forest, 36°51’15-28’’N, 102°36’’24’’- / 37’07’’E, 2236-2350 m, litter, dead wood / & moss sifted, 26. VI.2011, leg. M. Schülke ” [white, printed]; 1 ♂, “ CHINA: Gansu Prov. [CH11-13] / Lenglong Ling Mts., 80 km NNW / Honggu, 37°03’50.3’’N, 102°39’57.2’’E, / 3392 m, alpine pasture with / Rhododendron, litter, grass roots sifted / 30. VI.2011, leg. M. Schülke ” [white, printed]; 1 ♂, “ CHINA: Qinghai Prov. [CH11-09e] / Daban Shan, 62 km NNW Honggu / creek valley, Picea, Populus, Betula / forest, 36°51’15-28’’N, 102°36’’24’’- / 37’07’’E, 2236-2350 m, creek valley, / litter, dead wood / & moss sifted, / 10.VII.2011, leg. M. Schülke ” [white, printed]; 1 ♂, “ CHINA: Gansu Prov. [CH11-12] / Lenglong Ling Mts., pass road 61.5 km / N Honggu, 2875-2900 m, 36°53’11.0’’N, / 102°45’30.8’’E, dry grass steppe and / field edges, under stones, running on / trail, 29. VI.2011, leg. M. Schülke ” [white, printed], (cPJ, MNHB).
Diagnosis. Body nearly black; male metatrochanter distally produced into short and stout subtriangular spine, ventral margin of trochanter bent distally at an obtuse angle; aedeagus in ventral view distinctly more than twice as long as wide, its ventral plate wider than long, with distomedian subtriangular projection and pair of large subtriangular or rounded lateral lobes, dorsal plate elongate subtriangular with broadened subapical region and narrow truncate apex, endophallus in ventral view with two strongly elongate sub-parallel sclerites narrowing distally.
Description. Body of male (Fig. 14) elongate and slender, moderately convex, with long appendages, BL 1.68–1.90 mm; cuticle glossy, pigmentation nearly black with distinctly lighter, dark brown appendages, vestiture of setae lighter than cuticle.
Head in dorsal view round, broadest across eyes, HL 0.28–0.31 mm, HW 0.29–0.31 mm; in lateral view each temple 2.2–2.5 times as long as eye; vertex weakly convex and only slightly bulging posterodorsally; frons flattened; supraantennal tubercles small and indistinctly elevated. Eyes small and finely faceted, hardly projecting laterally from head silhouette, in lateral view oval. Punctures on vertex and frons inconspicuous, small and sparse; setae short and sparse, suberect, sparse and short thick bristles present on vertex and tempora. Antennae slender, indistinctly shorter than half BL, AnL 0.78–0.85 mm; antennomeres 1–2 strongly, 3–6 slightly elongate, 7–8 each about as long as broad, 9 and 10 each weakly transverse, 11 much shorter than 9–10 combined, about 1.6 times as long as broad.
Pronotum broadest in front of middle, PL 0.40–0.45 mm, PW 0.35–0.40 mm; anterior margin arcuate, lateral margins rounded in anterior half and nearly straight in posterior third, posterior corners slightly obtuse-angled, blunt; posterior margin weakly rounded. Pronotal base with single outer pair of faint pits. Punctures on pronotal disc inconspicuous; setae moderately dense and short, suberect and on sides mixed with thick bristles.
Elytra oval, broadest distinctly anterior to middle, EL 1.00– 1.13 mm, EW 0.65–0.70 mm, EI 1.50–1.69; basal impressions and humeral calli lacking, elytral apices separately rounded. Punctures on elytral disc inconspicuous, superficial; setae similar to those on pronotum, moderately dense and weakly suberect.
Legs long and slender, metatrochanter (Fig. 22) modified, with short and stout subtriangular distal spine, ventral margin of trochanter bent at an obtuse angle in distal region.
Metaventrite with deep oval median impression occupying most of its surface, extending on almost entire length.
Aedeagus (Figs 39–58) elongate, AeL 0.50 mm; median lobe in ventral view showing some variability, from nearly as long as broad to distinctly elongate, rapidly narrowing distally, ventral plate broader than long, with lateral pair of large subtriangular or rounded lobes and variously long distomedian projection; endophallus in ventral view (Figs 59–68) with two strongly elongate and approximately parallel sclerites narrowing distally, variable in shape. Dorsal wall lacking setae; parameres slender, each with 3 long subapical setae.
Female. Similar to male but with slightly smaller eyes (in lateral view temple nearly as long as 3 diameters of eye), lacking metaventral impression and with unmodified metatrochanters. BL 1.73–1.78 mm; HL 0.30 mm, HW 0.30 mm, AnL 0.73–0.80 mm; PL 0.43 mm, PW 0.38 mm; EL 1.00– 1.05 mm, EW 0.63–0.65 mm, EI 1.54–1.62.
Distribution. Central China: Central Gansu / easternmost Qinghai border area.
Etymology. The adjective aurilobatus alludes to the lateral earlike lobes of the aedeagus (after the Latin word auris, an ear).
Remarks. This species is most easily identifiable by its remarkable aedeagus, strongly differing from all Chinese congeners in the presence of large lateral lobes of the ventral plate. Variously shaped lateral lobes of the ventral plate are characteristic of Tetramelus of the reitteri group distributed in Caucasus and Transcaucasia (Vít & Hlaváč 1997, 1998), but none of these was reported to have a modified metatrochanter.
The available sample of specimens (all collected in mountains between Xining in Qinghai and Wuwei in Gansu) shows a great variability of the body length and proportions of body parts, most notably the elytral index, as well as some variability in the shape of the median lobe and the endophallic sclerites. The variability of external structures is not uncommon within West Palaearctic populations of wingless Tetramelus species (Jałoszyński, unpublished obs.). The aedeagus of each available specimen was studied, photographed and compared with all others in order to verify a hypothesis of more than one species being present in the sample. Examples are shown in Figs 39–68. Differences can be seen in shapes and proportions of various regions of the median lobe (lateral lobes, distomedian process of ventral plate, distal and proximal regions of median lobe), and, most notably, in the shapes of two endophallic sclerites. In the latter case, the sclerites are in all specimens asymmetrical, one being longer and more slender than the other, but their shapes vary and their placement in some specimens is inverted (compare Fig. 41 vs. 45, and 59 vs. 64). All males have the same shape of modified metatrochanters. In my opinion, differences found in the aedeagi represent intraspecific variability, and I treat all observed variants as belonging to a single species.
description: Published as part of Jałoszyński, Paweł, 2024, Subgenera Cladoconnus Reitter and Tetramelus Motschulsky of Euconnus Thomson discovered in China (Coleoptera, Staphylinidae, Scydmaeninae), pp. 232-256 in Zootaxa 5514 (3) on pages 241-244, DOI: 10.11646/zootaxa.5514.3.2, http://zenodo.org/record/13849780