Euconnus (Chenzhilinus) huapingensis Yin, 2024

Yin, Zi-Wei & Zhou, De-Yao, 2024, Chenzhilinus, a new subgenus of Euconnus Thomson (Coleoptera: Staphylinidae: Scydmaeninae) from southern China, Zootaxa 5541 (4), pp. 582-592 : 587-589

Euconnus (Chenzhilinus) huapingensis Yin & Zhou, sp. nov.

Chinese common name: AE坪ṀẆŵm

( Figs 1–4 )

Type material (2 exx.). HOLOTYPE: CHINA: ♂: ‘China: Guangxi, Guilin City, Lingui District, Anjiangping , Xiaoguangfuding , 25°33’44.95”N, 109°55’40.55”E, 1792 m, 27.v.2023, Peng, Zhou & Duan leg., 广®临桂 Ṙ 江坪 小广DZữ彭中Ẅ ’ ( SNUC). PARATYPE: CHINA: 1 ♂, same collecting data as for holotype ( SNUC) .

Diagnosis. As for the subgenus (vide supra), plus the following: Male. Body length approximately 2.0 mm; antennal club 0.51–0.53 mm long, formed by greatly broadened antennomeres 8–11, 8–10 subquadrate, gradually shorter, 11 roundly conical; elytral length/width 1.32–1.38; metacoxa with short, blunt projection on ventral margin; sternite III and IV each with pair of oval projections on posterolateral margins; stout aedeagus with two admesal macrosetae at apex of dorsal wall, endophallus composed of one subtrapezoidal, transverse, and one oval sclerite at middle. Female. Unknown.

Description. Male. Body (1A) moderately slender and dorso-ventrally weakly convex, length (combined length of head, pronotum and elytra) 1.97–1.98 mm; coloration uniformly reddish-brown, mouthparts and tarsi paler. Head ( Fig. 1B ) elongate sub-oval, broadest across eyes, length from anterior margin of clypeus to posterior margin of vertex 0.44–0.45 mm, width across eyes 0.39–0.41 mm; supraantennal tubercles barely raised; eyes small, weakly convex; tempora in dorsal view approximately 2.0× as long as eyes. Punctures on vertex and frons conspicuous, becoming slightly finer anteriorly; setae long and dense, suberect; temporal margins with much longer and denser bristles. Antenna moderately long, 1.02–1.04 mm long, club ( Fig. 1D ) formed by apical four enlarged antennomeres, occupying half-length of antenna, length 0.51–0.53 mm; antennomere 1 broad and slightly elongate, 2 slightly elongate, weakly broadening from base to apex, 3–7 compact, each distinctly transverse, of subequal width, antennomere 8 slightly wider and much longer than 7, subquadrate, 9 as wide as and much shorter than 8, 10 much shorter than 9, slightly transverse, 11 slightly longer than 10, subconical.

Pronotum ( Fig. 1B ) in dorsal view bell-shaped, broadest approximately at middle, length along midline 0.49– 0.51 mm, maximum width 0.49 mm; anterior margin slightly curved, sides slightly rounded, convergent from broadest point anteriorly and weakly narrowing toward base, posterior corners small and obtuse, posterior margin much broader than anterior margin, slightly convex at middle; pronotal base with two large, round pits, area between pits lacking carina, that posterior pits with fine wrinkles. Punctures of pronotal disc conspicuous and relatively sparse; setae similar to those of head, suberect, disc with sparse and margins with dense bristles.

Elytra together suboval and flattened dorsally, broadest at approximately basal 2/5, length along suture 1.04– 1.08 mm, maximum width 0.78–0.79 mm, length/width 1.32–1.38; basal impressions distinct, consisting of two pairs of large round pits; humeral calli greatly projecting; elytral apices separately rounded. Punctures on elytral disc similar to those of head and pronotum; setae moderately long and dense, suberect.

Legs moderately long and slender, unmodified except for metacoxae; preapical portion of mesotibia with tufts of golden setae; metacoxa with short, blunt tubercle ( Fig. 3E ; ct) on ventral margin.

Sternites 1 (III) and 2 (IV) each with one pair of disc-like tubercles on posterolateral margins ( Fig. 3E ; lst).

Aedeagus ( Fig. 1F, G ) rather stout, dorso-ventrally symmetric, length 0.22 mm, walls membranous; median lobe in dorsal view with apical plate broadly and abruptly narrowed at middle and protruding for short distance, apical margin emarginate at middle and with two admesal macrosetae, preapical region in lateral view slightly projecting; ventral plate indistinctly demarcated from dorsal plate by archived suture; parameres absent or completely fused with median lobe; endophallus composed of one short, transverse and another suboval sclerite at middle.

Female. Unknown.

Sexual dimorphism. The greatly enlarged antennal clubs, as well as modifications on metacoxae and sternite III and IV, are probable male sexual characters that are absent in female.

Distribution. Southwestern China: Guangxi.

Etymology. The species in named after its type locality, Huaping Nature Reserve.

Figures

FIGURE 1. Habitus of Euconnus (Chenzhilinus) huapingensis sp. nov., male. A. Dorsal view. B. Ventral view. C. Lateral view.

FIGURE 2. Morphology of Euconnus (Chenzhilinus) huapingensis sp. nov., male. A. Head and pronotum. B. Head, frontal view. C. Ditto, lateral view. D. Antennal club. E. Prothorax, lateral view. Abbreviations: a8–11 = antennomere 8–11; abp = antebasal pit; bep = basal elytral pit; cl = clypeus; fr = frons; gen = genae; gp = gular plate; hyr = hypomeral ridge; lb = labrum; md = mandible; mp = maxillary palpus; mp1–4 = maxillary palpomere 1–4; mt = mesal tooth; pr = pronotum; tm = tempora; vt = vertex. Scale bars: 0.3 mm in A; 0.2 mm in B–F.

FIGURE 3. Morphology of Euconnus (Chenzhilinus) huapingensis sp. nov., male. A. Head, ventral. B. Prosternum. C. Pronotal and elytral base. D. Meso- and metaventrite. E. Apex of metaventrite and base of abdomen. Abbreviations: abp = antebasal pit; bep = basal elytral pit; bst = basisternal part of prosternum; ct = coxal tubercle; hc = hypostomal carina; hyr = hypomeral ridge; fr = hypostomal ridge; gen = genae; gp = gular plate; ihy = inner region of hypomeron; lst = lateral sternal tubercle; md = mandible; mn = mentum; mp1–4 = maxillary palpomere 1–4; msc = mesocoxa; msvp = mesoventral intercoxal process; mtc = metacoxa; mtvp = metaventral intercoxal process; mt = mesal tooth; nss = notosternal suture; pcr = procoxal rest; prp = prepectus; smn = submentum; ptp = posterior tentorial pit; sIII–V = sternite III–V. Scale bars: 0.2 mm.

FIGURE 4. Aedeagus of Euconnus (Chenzhilinus) huapingensis sp. nov., male (A, C, E. Photographic. B, D, F. Schematic). A, B. Ventral view. C, D. Lateral view. E, F. Dorsal view. Scale bars: 0.1 mm.