Skleroprotopus tiankeng Chen, Zhao, Golovatch & Liu, 2024, sp. nov.

3.3. 2.Skleroprotopus tiankengsp. nov. Figures 2 E, 3 C, 5 Material examined. Holotype male (SCAU), China, Shaanxi Province, Hanzhong City, Nanzheng District, Cave Xigoutiankeng Dong, 32°49′37.91′′N 107°1′37.77′′E, 850 m, 6. IX. 2017, Tian Mingyi, Huang Sunbin, Wang Dianmei and Yin Haomin leg. Paratypes: 4 males, 8 females (SCAU), same data as for holotype. Diagnosis. Differs from congeners mostly based on the following combination of characters: (1) penis much longer than coxae 2 (Fig. 5 I); (2) male leg 7 with a very small coxal process, lower than the telopodite (Fig. 5 E); (3) anterior gonopod (Fig. 5 G, H) with a large and foot-shaped like coxal process, carrying a broadened membranous lobe, outer margin with a triangular protrusion, and a relatively thick flagellum. — In addition, this new species differs from all other species analyzed in a> 10.3 % uncorrected p - distance of the COI barcoding gene. Etymology. The species is named after its type locality that is the Hanzhong sinkhole group, a geological wonder composed of multiple heavenly pits. “ Tiankeng ” in Chinese “ 天坑 ”, a noun in apposition. Description. Length of both sexes ca 29.0– 38.9 mm, width 1.9–2.2 mm, midbody height 1.8–2.1 mm, body with 49–63 podous + 1 apodous rings + telson. Natural coloration generally yellow to brownish. Antennae and legs light yellowish (Fig. 2 E). Eye patches transparent, subtriangular, arranged in 4–6 irregular rows, altogether about 18–27 (males) or 15–40 (females) ommatidia per eye patch. Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2 + 2 supra-labral and 8 + 8 labral setae. Antennae long, reaching behind to anterior of ring 4 when stretched dorsally (Fig. 3 C). In length, antennomeres 3> 5> 2> 4 ≈ 6> 1 ≈ 7 (Fig. 5 C). Antennomeres 5, 6 and 7 each with a distal corolla of sensilla basiconica. Mandibular stipes enlarged, with two small lobes in males, well-rounded in females. Gnathochilarium with at least 3–8 setae on each lamella lingualis (ll) in males; promentum (pr) columnar in males, anteriorly swollen and tubular in shape (Fig. 5 B), vs a broad conical pr in females (Fig. 5 A). Collum with marbled brownish spots and 8–10 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with 3 irregular subtransverse striae and metazona with 13–24 longitudinal striae laterally (Fig. 3 C). Suture dividing pro- and metazona rather narrow, a nearly regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites. Epiproct slightly protruding caudad, posterior margin with 6 + 6 setae. Paraprocts convex, with 1 + 1 setae. Hypoproct eye-shaped, with 1 + 1 setae. Legs long and slender, about 1.4 × as long as midbody height. Male leg-pair 1 (Fig. 5 D) hypertrophied, 5 - segmented, strongly curved anteriad. Coxa (cx) and telopoditomeres 1 and 2 (t 1, t 2) each with few long setae, others mostly short. Telopoditomere 3 (t 3) longest, about equivalent in length to the sum of the cx and t 1–2; Telopoditomere 4 (t 4) irregularly shaped, with several long setae subapically. Male leg-pair 2 (Fig. 5 I) reduced in size; penis (pn) pyramid-shaped, much longer than coxae (cx), distal part with two long setae (Fig. 5 I). Male leg-pair 7 (Fig. 5 E) reduced, with 3 - segmented telopodites, telopoditomere 2 (t 2) largest and setose subapically; coxal process (cp) small, much lower than telopodite, densely setose at mesal margin. Anterior gonopods (Fig. 5 G, H) with a large, foot-shaped like coxal process (cp) bearing with a long row of short villi in anterior view, posteriorly carrying with a broadened, and high membranous lobe (ml), slightly shorter than cp, middle outer margin of ml with a triangular protrusion. Flagellum (f) very long and relatively thick, distally spinulose-villose. Telopodite (te) about half as long as cp, with long setae apically, laterobasally with a minute remnant (r) of a second podomere. Posterior gonopods (Fig. 5 F) erect and stout, deeply branched at tip, anterior branch smooth, with a pointed tip, higher than a densely setose posterior one. Vulva (Fig. 5 J) mostly wrapped inside a membrane, characteristic in shape, strongly elongated; operculum (op) longer than bursa, with two parallel rows of short setae on anterior and posterior surfaces, and with at least 10 long distal setae. Remarks. The geological relic resources of Sinkhole Group at Hanzhong are mainly distributed within Xiaonanhai Town of Nanzheng District, Luojiaba Town of Xixiang County, Chanjiayan Town of Ningqiang County, and Sanyuan Town of Zhenba County, with a total area of about 5019 km 2. This new species lives in Xigoutiankeng Dong of Xiaonanhai Town, a cave that is about to be developed to the public. Based on the unpigmented body, transparent eyes, as well as long legs, S. tiankeng sp. nov. is considered a troglobite.