Euconnus (Chenzhilinus) huapingensis Yin & Zhou 2024, subgen. nov.

Chenzhilinus Yin & Zhou, subgen. nov. (of Euconnus) Chinese common name: ŘNJṀẆŵm亚¶ (Figs 1–4) Type species: Euconnus (Chenzhilinus) huapingensis sp. nov. Diagnosis. Chenzhilinus differs from all other subgenera by two potentially apomorphic character states, e.g., submentum laterally demarcated by additional pair of hypostomal carinae, and aedeagus lacking parameres, plus following combination of characters variably present in Euconnus s. str. species: antennae with tetramerous antennal club composed of four distinctly enlarged antennomeres; bristles present on vertex, tempora, and gene of head, anterolateral, lateral, and lateroventral area of pronotum, and mesanepisternum of the thorax; pronotum broadest at middle, weakly convergent from broadest point posteriorly, with pair of large antebasal pits, lacking sublateral carinae; hypomeral ridges and notosternal sutures complete; mesoventral intercoxal process broad, keel-like, entirely greatly projecting ventrally; elytra each with two large basal pits, humeral calli projected, metathoracic wings fully developed. Description. Male. General body shape (Fig. 1) elongate, body deeply constricted between head and pronotum; head, prothorax, and elytra weakly convex; appendages moderately long and slender, vestiture of setae normally developed, thick bristles present on vertex, tempora, and gene of head, and anterolateral, lateral, and lateroventral area of pronotum, anterolateral margins of mesothorax and on metaventrite. Pigmentation of cuticle reddish-brown. Head capsule (Figs 2A, C, 3A) divided by occipital constriction into large anterior and small posterior part (‘neck region’), posterior part retracted into pronotum. ‘Neck’ region much narrower than vertex, short and subcylindrical; narrowest site of occipital constriction about as wide as half head width. Anterior part of head ‘anthiciform’, i.e., approximately pentagonal, broad and flattened, broadest at anteriorly located eyes. Dorsum of head (Fig. 2C) almost flat; tempora (Fig. 2A, C; tm) much longer than compound eyes (Fig. 2C; ce) and with bristles; vertex (Fig. 2A, C; vt) strongly transverse, anteriorly confluent with subtrapezoidal, transverse frons, which is steeply lowering anteriorly in front of weakly raised supraantennal tubercles; frons and vertex sparsely setose; genae (Figs 2C, 3A; gen) and postgenae together elongate, convex, covered with thick bristles. Clypeus (Fig. 2A–C; cl) confluent with frons (Fig. 2A–C; fr), lacking frontoclypeal groove. Ventral side of head (Figs 2C, 3A) flattened; gular plate (Figs 2E, 3A, B; gp) lacking sutures, anterior part adjacent to posterior tentorial pits with convergent margins; posterior tentorial pits (Fig. 3A; ptp) elongate, located anteriorly to transverse impression separating ‘neck’ region from anterior part of head. Mouthparts (Figs 2B, 3A). Labrum (Fig. 2B, C; lb) transverse, with rounded and anteriorly roundly convergent sides and broadly rounded anterior margin with broad and shallow median emargination, dorsal surface with one transverse row of long setae and epipharynx with several elongate sensilla extending anteriorly beyond anterior labral margin and visible in dorsal view. Mandibles (Figs 2B, C, 3A) symmetrical, moderately large, broad only at base and curved, markedly slender, with pointed apical tooth, and small tooth (Figs 2B, 3A; mt) located at submedian region of mesal mandibular margin; prostheca elongate, composed of numerous dense trichia occupying narrow sub-basal mesal area. Maxilla (Fig. 3A) elongate, with transverse cardo; subtriangular and elongate basistipes; elongate and broad mediostipes; elongate galea and lacinia with long and dense trichia along distal and mesal margin; maxillary palpus (Figs 2B, C, 3A; mp, mp1–4) long and slender, palpomere 1 small but strongly elongate, 2 long and distinctly thickening distally, pipe-like, 3 longer than 2 and strongly broadening distally, broadest near middle, 4 small, subconical and slender, with elongate and pointed apical palpal cone. Labium with subtriangular submentum (Fig. 3A; smn) laterally demarcated by pair of posteriorly convergent hypostomal carinae (Fig. 3A; hc); mentum (Fig. 3A; mn) subtrapezoidal; prementum short, with distinctly demarcated, glabrous ligula; labial palps (Figs 2C, 3A) much shorter than mentum, palpomere 1 short, 2 strongly elongate and weakly broadening distally, 3 long and slender, narrowing distally. Posteriorly and laterally mouthparts demarcated by hypostomal ridges (Fig. 3A; hr) which are moderately curved and extending nearly up to posterior tentorial pits, but posteriorly not connected. Antennae (Figs 1, 2D) moderately slender and moderately long, antennomeres 1–7 compact, four terminal antennomeres forming distinct club (Fig. 2D; a 8–11). All antennomeres covered with sparse long setae. Prothorax (Figs 1, 2E, 3B) weakly convex, in dorsal view (Fig. 1A) bell-shaped, broadest near middle; lateral margins slightly convergent posteriorly from broadest point. Pronotum (Fig. 2A, E; pr) lacking sublateral carinae. Base of pronotum with only one pair of relatively large and deep lateral antebasal pits (Figs 2A, 3C; abp). Pronotal disc regularly setose, lateral portions above hypomeral ridges with thick and dense bristles (Fig. 2E). Prosternum (Fig. 3B) about half as long as pronotum, with basisternal part (Fig. 3B; bst) short and indistinctly demarcated from procoxal cavities; prosternal intercoxal process indistinct, developed as diffused median longitudinal elevation; procoxal sockets closed by posterolateral expansions of prosternum and posteromesal lobes of hypomera. Hypomera elongate, with strongly curved inner (adcoxal) margins, each divided by entire hypomeral ridge (Figs 2E, 3B; hyr) into small subtriangular inner (adcoxal) part (Fig. 3B; ihy) and large external part fused with sides of pronotum; notosternal sutures (Fig. 3B; nss) complete and arcuate. Elytra (Fig. 1A, C) together suboval and relatively slender, dorsally flattened, with rounded apices; elytral base about as broad as pronotal base, with projecting humeral calli (Fig. 3C); each elytron with two distinct asetose basal elytral pits (Fig. 2A, 3C; bep). Metathoracic wings fully developed. Mesoventrite (Fig. 3D) moderately short, much broader than long, with broad anterior ridge bearing subtriangular median projection connected with long, slender and keel-like mesoventral intercoxal process (Fig. 3D; msvp) greatly raised ventrally (Fig. 1C; msvp), process posteriorly fused with metaventrite, with broad intercoxal portion; mesoventrite posterior to anterior ridge with pair of broad, sparsely setose impressions functioning as procoxal rests (Fig. 3D; pcr) separated from mesocoxal cavities by slightly oblique ridge; mesocoxal sockets located laterally. Prepectus (Fig. 14; pre) massive, posterior part of mesanepisternum partly visible in ventral view, with dense lateral bristles (Fig. 3D). Metaventrite (Fig. 3D) much longer than mesoventrite, subquadrate in shape, anteriorly fused with mesoventrite, lateral margins slightly rounded, lateral (admetacoxal) parts of posterior margin slightly curved, at middle posterior margin expanded posteriorly and forming relatively narrow and subtrapezoidal metaventral intercoxal process (Fig. 3D; mtvp); most part of ventrite distinctly punctate and covered with long setae, in anterior part with sparse and thick bristles at middle. Legs moderately long and slender; mesotibia in male with preapical setose tuft (Fig. 2F); tarsomeres lacking ventrodistal lobes. Abdomen (Fig. 1B) elongate, roundly triangular; abdominal sternites III–VIII gradually narrowing towards abdominal apex, sternite III longest, with shallow metacoxal cavities each demarcated posteriorly by curved coxal line; suture between sternite VII and VIII less distinct than between remaining sternites. Propygidium hidden under elytra, weakly sclerotized; pygidium exposed in intact specimens, strongly sclerotized, subtriangular with rounded apex, covered with setae. Sternite IX large, broad and transverse, with nearly straight anterior margin, lateral margins weakly and evenly divergent posteriorly; tergite IX reduced to lateral apodemes fused with posterolateral margins of sternite IX; tergite X subtrapezoidal, with almost straight posterior margin. Aedeagus (Fig. 4) with symmetric median lobe, moderately stout; dorsal and ventral plate discriminated vaguely by archived suture; endophallus symmetric, with two sclerotized components at middle; parameres absent. Female. Unknown. Etymology. The new generic name is dedicated to Zhi-Lin Chen, who provided continuous support during our field activities in Guangxi. Included species. This subgenus currently includes only one species (described below) distributed in Guangxi, southern China.