Sichuana taiji Shen, Yin & He, 2025

Sichuana taiji Shen, Yin & He View in CoL sp. nov. 太RḨậ

Figs. 2–11 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11

Diagnosis. The new species superficially resembles Sichuana planicercata Gu, Zheng & Yue, 2023 , but can be differentiated from the latter by the following characters: 1) male left tegmina with more numerous distinct stridulatory teeth, and 2) male cercus inner basal part robust and expand inward.

In addition, Sichuana taiji sp. nov. can be differentiated from S. curvicercata Gu, Zheng & Yue, 2023 by the following characters: 1) male left tegmina with more numerous distinct stridulatory teeth, 2) posterior margin of male 10th abdominal tergite medially with a shallow concave, form a pair of lobate projections, and 3) male cercus slightly bent toward ventral side, but apex not pointing dorsally, inner tooth not straight which apex not suddenly sharp and incurved.

Sichuana taiji View in CoL sp. nov. can be differentiated from S. longilamina Gu, Zheng & Yue, 2023 View in CoL by the following characters: 1) prosternum with a pair of distinctly smaller processes, 2) lateral field of male tegmen relatively narrower, 3) posterior margin of male 10th abdominal tergite with a depressed wide rounded area, 4) male cercus not pointing dorsally and basal part of inner tooth more robust, and 5) male subgenital plate not elongate, with a relatively shorter styli.

Sichuana taiji View in CoL sp. nov. can be differentiated from S. cryptospina Shen & Yin, 2020 View in CoL by the following characters: 1) prosternum with a pair of distinctly smaller processes, 2) lateral field of male tegmen relatively narrower, and left tegmina with more numerous distinct stridulatory teeth, 3) basal part of inner tooth on male cercus robust and expand inward.

Sichuana taiji View in CoL sp. nov. can be differentiated from S. feicui He, 2020 View in CoL by the following characters: 1) prosternum with a pair of distinctly smaller processes, 2) lateral field of male tegmen relatively narrower, 3) male cercus strongly incurved at the middle which apex acute, basal part of inner tooth robust and expand inward.

Sichuana taiji View in CoL sp. nov. can be differentiated from S. magnicerca Gu, Zheng & Yue, 2023 View in CoL by the following characters: 1) prosternum with a pair of distinctly smaller processes, 2) lateral field of male tegmen relatively narrower, 3) male cercus relatively smaller and shorter, not extending beyond subgenital plate, with inner tooth distinctly larger, basal part robust and expanded inward.

Description. Male. Body relatively large in Drymadusini .

Head. Frons slightly oblique backward. Fastigium of vertex slightly wider than the scape of antenna ( Figs. 2 View FIGURE 2 AB). Median ocellus visible, oval ( Fig. 2A View FIGURE 2 ). Compound eyes broadly round and projecting outward ( Figs. 2 View FIGURE 2 ABC).

Thorax. Disc of prozona with a broadly obtuse concavity in the middle of each side, anterior margin of pronotum slightly concave and posterior margin blunt, lateral carina faintly indicated in prozona and distinct in metazona, first transverse sulcus slightly concave backward, central transverse sulcus “V” shaped, posterior transverse sulcus absent, median carina distinct in prozona and slightly obscure in metazoan, lateral lobes longer than deep, with weakly humeral sinus ( Figs. 2 View FIGURE 2 ABC). Prosternum with a pair of small conical processes ( Fig. 2D View FIGURE 2 ). Mesosternum with a pair of acute triangular lobe-shaped processes, nearly equal in width to height; metasternum with a pair of obtuse triangular lobe-shaped processes, width distinctly broader than height ( Fig. 2D View FIGURE 2 ).

Wings. Mesopterous, about 1.3 as long as pronotum, with clear longitudinal and cross veins; lateral field gradually and slightly widens from base, apical half not distinguish expend ( Figs. 2 View FIGURE 2 EFHI, 3AB). C weak, reach about 3/5 of the wings ( Fig. 3A View FIGURE 3 ). Sc strong, with 3–4 branches, first branches sometimes fused with C which reach about 4/5 of the wings ( Fig. 3A View FIGURE 3 ). Rs branching about in basal 2/3 part of tegmina, with 2 branches ( Fig. 3A View FIGURE 3 ). Stridulatory file on Cu2 of left tegmina with 3/5 basal part bearing 27–31 distinct stridulatory teeth, and 2/5 apical part with about 50 indistinct small teeth ( Figs. 2G View FIGURE 2 , 6A View FIGURE 6 ). Stridulatory file on Cu2 of right tegmina with 2/5 basal part with about 30 indistinct small teeth, and 3/5 apical part bearing 29–35 distinct stridulatory teeth ( Fig. 2J View FIGURE 2 ). Mirror on right tegmina ovoid, around 1.3 times longer than wide ( Fig. 2J View FIGURE 2 ). Hind wings rudimentary, longer than half of the pronotum, 3 primary veins with relatively high numbers of spinules, and 1 primary vein with a few spinules sparsely arranged ( Figs. 2K View FIGURE 2 , 6C View FIGURE 6 ).

Leg. Fore coxae with 1 long spine; fore femora shorter than pronotum, dorsally unarmed, ventrally with 1–4 internal spinules and externally unarmed, genicular lobes with 0–2 internal spinules and externally unarmed; fore tibiae both sides with crack-shape tympana, dorsally with 3 externally spines and internally unarmed, ventrally with 6 pair of spines, a pair at the apical. Middle femora dorsally unarmed, ventrally with 0–2 internal spinules and 0–4 external spines, genicular lobes with 1 internal spinule and 1–2 external spinules; middle tibiae dorsally with 4 internal spines and 2 external spines, ventrally with 6 pair of spines, a pair at the apical. Hind femora dorsally unarmed, ventrally with 4–10 internal spinules and 6–10 external spinules, genicular lobes unarmed; hind tibiae dorsally with 20–27 spines on both sides and 1 pair of apical spurs, ventrally with 5–8 spines on both sides, 1 pair of subapical spines, and 2 pair of apical spurs.

Abdomen. Posterior margin of 10 th abdominal tergite with a wide rounded area, which pileous, slightly depressed, and posterior margin medially with a shallow notch, its sides forming a pair of round, blunt lobes, which lack strongly sclerotized margins ( Figs. 4 View FIGURE 4 ACD, 7AD). Epiproct triangular, visible from dorsal view. Cercus stout, pileous and conical, incurved at obtuse angle from midlength, slightly bent ventrally, apex acute; with inner tooth near base, basal part robust and expanded inward, apical part gradually thined and incurved, apex acute. Subgenital plate length greater than width, with 2 lateral carinae, posterior margin medially with a deep sharped notch; width of notch varies; stylus slender and obviously longer than notch ( Figs. 4B View FIGURE 4 , 7C View FIGURE 7 ).

Genitalia. Titillators “L” shaped, with long apical portions basal bear 3 row of denticles, and some scattered denticles in addition ( Figs. 4E View FIGURE 4 , 7B View FIGURE 7 ).

Female. Generally similar to male. Tegmina brachypterous, slightly shorter than pronotum ( Figs. 5 View FIGURE 5 CF). Hind wings rudimentary, brachypterous, longer than half of the pronotum ( Figs. 5I View FIGURE 5 , 8 View FIGURE 8 EH). Cercus conical and pileous ( Figs. 5G View FIGURE 5 , 8F View FIGURE 8 ). Posterior margin of 10 th abdominal tergite with a wide rounded area, which pileous, slightly depressed ( Fig. 8G View FIGURE 8 ). Subgenital plate nearly trapezoid, width greater than length, with 2 lateral carinae, middle of posterior margin with a wide triangular shallow notch ( Figs. 5H View FIGURE 5 , 8G View FIGURE 8 ). Ovipositor shorter than hind femora, obviously beyond apex of hing femora, apical part slightly decurved ( Fig. 5D View FIGURE 5 ).

Coloration. Body dorsally generally brown, dark brown, yellowish brown, or reddish brown, with much irregular light patches; ventrally light yellowish brown or rosybrown. Median ocellus light yellowish brown. Compound eyes black, upper part light while alive. Tegmina generally yellowish brown or dark brown, male stridulatory apparatus area on dorsal field black, lateral field with numbers of black irregular patches. Spinules on hind femora black. Ovipositor dark brown, apical part black.

Measurements (mm). Body (from head to tip of abdomen): ♂ 21.07–34.06, ♀ 23.24–33.46; pronotum: ♂ 7.05– 8.46, ♀ 7.53–8.50; tegmina: ♂ 8.58–14.29, ♀ 6.24–7.93; fore femora: ♂ 5.74–7.26, ♀ 7.16–7.70; middle femora: ♂ 6.57–8.17, ♀ 7.42–8.65; hind femora: ♂ 17.34–22.02, ♀ 22.48–24.77; fore tibiae: ♂ 6.76–7.96, ♀ 7.42–8.65; middle tibiae: ♂ 7.30–9.02, ♀ 9.28–9.65; hind tibiae: ♂ 16.24–21.28, ♀ 21.15–24.47; ovipositor: 17.31–20.63.

Material examined. Holotype: ♂, China, Sichuan Province, Ngawa Tibetan and Qiang Autonomous Prefecture , Heishui County, Seergu Town , Seergu Village ( 103°25’43.17” E, 31°55’14.95” N, alt. 1850m), 5-VIII-2022, coll. Lu Qiu & Chengbin Wang. GoogleMaps Paratypes: 1♂ 1♀, same data as for holotype GoogleMaps ; 2♀, China, Sichuan Province, Ngawa Tibetan and Qiang Autonomous Prefecture , Heishui County, Seergu Town , Seergu Village ( 103°24’32.29” E, 31°55’44.24” N, alt. 2442m), 15-VII-2023, coll. Tianxuan Gu & Xiwen Chen. GoogleMaps

Remarks. The new species has some small differences at different altitudes. For example, the individuals distributed at 2442m are larger, and the male has more distinct stridulatory teeth on the left tegmina and less distinct stridulatory teeth on the right tegmina. It may be caused by the differentiation of different populations ( Fig. 1 View FIGURE 1 ), but it has not yet reached a level of divergence that forms different species.

Etymology. The species is named after the Chinese philosophy, Taiji. Male cercus is shaped like one half of the Taiji diagram.

Distribution. Sichuan ( China). Known only from the type locality.