Holotype male (SCAU), China, Qinghai Province, Xining City, Chengzhong District, Nanshan Park, 36°36′3.78″N 101°46′6.08″E, 2400 m, 18.VIII.2020, Yu Tiantian leg.

Differs from congeners mostly based on the following combination of characters: (1) leg 1, 6-segmented (Fig. 4D); (2) penis much shorter than coxae 2 (Fig. 4F); (3) coxal process of leg 7 (Fig. 4E) tongue-shaped, about 2× as long as a club-shaped telopodite; (4) anterior gonopod with a very long and narrow coxal process, carrying an irregularly dentate and membranous lobe (Fig. 4I). — In addition, this new species differs from all other species analyzed in a >12.7% uncorrected p-distance of the COI barcoding gene.

The specific epithet is honored to Dr. Yu Tiantian (余甜甜) (Kunming Institute of Zoology, Chinese Academy of Sciences), who is the collector; noun in the genitive case.

Length of holotype ca 25.0 mm, 1.6 mm in diameter, body with 53 podous + 1 apodous rings + telson. Coloration in alcohol marbled dark brownish, slightly lighter in anterior 1/3 body (Fig. 3F). Antennae semi-transparent, gradually infuscate from base to end, antennomeres 5 and 6 darkest, frosted violet (Fig. 4C). Eye patches blackish, triangular, arranged in 6 irregular rows, about 35 (left) or 43 (right) ommatidia per eye patch (Fig. 4B). Legs pale yellow.

Head capsule (Fig. 4B) smooth and hairless, vertex bulged, epicranial suture obviously concave. Labral margin with 2+2 supra-labral and 6(7)+6(7) labral setae (Fig. 4A). Antennae (Fig. 4C) medium in length, reaching behind to middle of ring 2 when stretched dorsally. In length, antennomeres 3>2>4>6≈5>1>7. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Antennomere 7 invaginated terminally, sensory cones inconspicuous. Mandibular stipes enlarged, with two nearly equal lobes (Fig. 3F). Gnathochilarium with at least 4 setae on each lamella lingualis (ll); promentum (pr) long and diamond-shaped, swollen anteriorly (Fig. 4A).

Collum (Fig. 3F) with 6 lower striae laterally, but lowest stria not reaching the anterior margin. Prozona delicately alveolate, metazona laterally with 13–18 longitudinal striae (Fig. 3F). Suture dividing pro- and metazona narrow, a regular comb. Ozopores starting with ring 6, lying anteriorly on lateral sides of metatergites.

Epiproct slightly protruding caudad, with 2+2 setae along posterior margin. Paraprocts convex, medially with 2+2 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs (Fig. 3F) short, about 0.7× as long as midbody height, claw weakly curved, without modifications. Male leg-pair 1 (Fig. 4D) hypertrophied, strongly curved anteriad, 6-segmented, but dividing line (dl) between telopoditomeres 4 and 5 (t4, t5) incomplete. Both t4 and t5 combined longest, irregularly shaped, with a few scattered setae and short bristles medially. Coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) broadest. Male leg-pair 2 (Fig. 4F) reduced in size and slender; penis (pn) unpaired, shorter than coxae (cx), cylindrical, distal part with two long setae. Male leg-pair 7 (Fig. 4E) strongly modified, with 2-segmented telopodites, club-shaped, densely setose apically, telopoditomere 2 rather small. Coxal process (cp) strongly elongated, tongue-shaped, about 2× as long as telopodite (te), clothed with dense long bristles.

Anterior gonopods (Fig. 4H, I) with a very long and rather slender coxal process (cp) bearing a long row of short villi in anterior view, posteriorly carrying with an irregularly dentate membranous lobe (ml), outer margin of ml distinctly broadened and reflexed, subtriangular, distally sharp. Flagellum (f) long and slender, a little barbed. Telopodite (te) about 2/3 as long as cp, with long setae apically.

Posterior gonopods (Fig. 4G) erect and thin, anterior branch slender, tapering regularly towards tip, higher than posterior branch, and both densely setose distally.

Female unknown.

The Nanshan Park, Xining City, Qinghai Province is nicely forested in 80% of its area, dominated by hardwood tree species including Picea crassifolia Kom., 1923, Juniperus przewalskii Kom., 1924 and Pinus tabuliformis Carrière, 1867. The holotype of Skleroprotopus yutiantianae sp. nov. was found in forest litter.

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.

Differs from congeners mostly based on the following combination of characters: (1) penis much longer than coxae 2 (Fig. 5I); (2) male leg 7 with a very small coxal process, lower than the telopodite (Fig. 5E); (3) anterior gonopod (Fig. 5G, 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.

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.

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. 2E). Eye patches transparent, subtriangular, arranged in 4–6 irregular rows, altogether about 18–27 (males) or 15–40 (females) ommatidia per eye patch.

Figure 2. 

Pictures of live animals, photos by Prof. Mingyi Tian from SCAU. A Skleroprotopus change sp. nov.; B Skleroprotopus megistus sp. nov.; C Skleroprotopus longissimus sp. nov.; D Skleroprotopus genjudi sp. nov.; E Skleroprotopus tiankeng sp. nov.; F Skleroprotopus laiyuanensis sp. nov.; G Skleroprotopus incisodentatus sp. nov.

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. 3C). In length, antennomeres 3>5>2>4≈6>1≈7 (Fig. 5C). 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. 5B), vs a broad conical pr in females (Fig. 5A).

Figure 3. 

Habitus of some Skleroprotopus species in lateral view. A Skleroprotopus penglai sp. nov.; B Skleroprotopus longiflagellatus sp. nov.; C Skleroprotopus tiankeng sp. nov.; D Skleroprotopus ampullaceus sp. nov.; E Skleroprotopus conicus sp. nov.; F Skleroprotopus yutiantianae sp. nov.; G Skleroprotopus multistriatus sp. nov.; H Skleroprotopus change sp. nov. Scale bars: 5.0 mm.

Figure 4. 

Skleroprotopus yutiantianae sp. nov., holotype. A gnathochilarium; B head and collum, dorsal view; C left antenna, lateral view; D legs 1, anterior view; E legs 7, anterior view; F legs 2 with penis, posterior view; G posterior gonopods, anterior view; H anterior gonopods, anterior view; I anterior gonopods, posterior view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; dl, dividing line; f, flagellum; ll, lamella lingualis; ml, membranous lobe; pn, penis; pr, promentum; t1–t5, telopoditomeres 1–5; te, telopodite. Scale bars: 0.2 mm.

Figure 5. 

Skleroprotopus tiankeng sp. nov.. A, J female paratype, B–I male paratype. A, B gnathochilarium; C right antenna, lateral view; D legs 1, anterior view; E legs 7, anterior view; F posterior gonopods, posterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I legs 2 with penis, posterior view; J right vulva, lateral view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

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. 3C). 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. 5D) hypertrophied, 5-segmented, strongly curved anteriad. Coxa (cx) and telopoditomeres 1 and 2 (t1, t2) each with few long setae, others mostly short. Telopoditomere 3 (t3) longest, about equivalent in length to the sum of the cx and t1–2; Telopoditomere 4 (t4) irregularly shaped, with several long setae subapically. Male leg-pair 2 (Fig. 5I) reduced in size; penis (pn) pyramid-shaped, much longer than coxae (cx), distal part with two long setae (Fig. 5I). Male leg-pair 7 (Fig. 5E) reduced, with 3-segmented telopodites, telopoditomere 2 (t2) largest and setose subapically; coxal process (cp) small, much lower than telopodite, densely setose at mesal margin.

Anterior gonopods (Fig. 5G, 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. 5F) erect and stout, deeply branched at tip, anterior branch smooth, with a pointed tip, higher than a densely setose posterior one.

Vulva (Fig. 5J) 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.

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 km². 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.

Holotype male (SCAU), China, Shaanxi Province, Xi’an City, Wangchuan County, Cave Lingyun Dong, 34°4′21.3′′N 109°23′45.01′′E, 900 m, 14.IX.2017, Tian Mingyi, Huang Sunbin, Wang Dianmei and Yin Haomin leg. Paratypes: 6 males, 2 females (SCAU), same data as for holotype.

Differs from congeners mostly based on the following combination of characters: (1) telopoditomere 3 of male leg 1 particularly broad and bulging in the middle (Fig. 6E); (2) penis subequal in height to coxae 2 (Fig. 6F); (3) coxal process of male leg 7 very small, lower than the telopodite (Fig. 6D); (4) anterior gonopod with a long coxal process carrying a highly developed, axe-shaped, membranous lobe (Fig. 6I). — In addition, this new species differs from all other species analyzed in a >10.3% uncorrected p-distance of the COI barcoding gene.

Figure 6. 

Skleroprotopus megistus sp. nov.. A, D–J male paratype; B, C female paratype. A, B gnathochilarium; C left vulva, lateral view; D legs 7, anterior view; E legs 1, anterior view; F legs 2 with penis, posterior view; G posterior gonopods, anterior view; H anterior gonopods, anterior view; I anterior gonopods, posterior view; J posterior gonopods, posterior view. Abbreviations: cp, coxal process; cx, coxa; f, flagella; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1-t4, telopoditomeres 1-4; te, telopodite. Scale bars: 0.2 mm.

Latinised Greek “megistus” is meaning “large”. The specific epithet refers to the male leg-pair 1 being particularly large; adjective.

Length of both sexes ca 31.5–40.0 mm, 1.8–2.2 mm in diameter, body with 53–65 podous + 1 apodous rings + telson. Natural coloration generally pale reddish brown (Fig. 2B), in alcohol marbled yellowish brown. Antennae and legs light yellowish. Eye patches blackish, triangular, arranged in 4–6 irregular rows, altogether about 22–52 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 4+4 supra-labral and 12+12 labral setae. Antennae very long and slender, reaching behind to middle of ring 5 when stretched dorsally. In length, antennomeres 3>2>4≈5>6>1>7. Antennomeres 5, 6 and 7 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded in males, more rounded in females. Gnathochilarium with at least 5 setae on each lamella lingualis (ll); promentum (pr) lance-shaped at base, swollen anteriorly, olive-shaped in males (Fig. 6A), vs a narrow rhomboid pr in females (Fig. 6B).

Collum with marbled brownish spots and 8–10 lower striae laterally, but lowest 3 striae not reaching the anterior margin. Prozona with 3–4 subtransverse striae and metazona with 13–22 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites (Fig. 2B).

Epiproct slightly protruding caudad, posterior margin with 3+3 setae. Paraprocts convex, medially with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs medium-sized, about as long as midbody height. Male leg-pair 1 (Fig. 6E) hypertrophied, 5-segmented, tip slightly curved anteriad. Coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) widest and largest, bulging in the middle. Telopoditomere 4 (t4) subtriangular; t3 and t4 devoid of long setae. Male leg-pair 2 (Fig. 6F) reduced in size; penis (pn) subequal in height to coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 6D) reduced, with 2-segmented telopodites (te), t1 large and setose subapically; coxal process (cp) very small, lower than telopodite (te), with several long setae distally.

Anterior gonopods (Fig. 6H, I) with a very long coxal process (cp) bearing an oval field of short villi in anterior view, posteriorly carrying with a highly developed, axe-shaped, membranous lobe (ml), slightly lower than cp, outer margin of ml with a large, sharp and triangular protrusion, clearly wider than cp. Flagellum (f) very long and slender, villose in distal part. 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. 6G, J) stout, anterior branch slender and with a small pointed tip, posterior one semi-annulate and densely setose distally.

Vulva (Fig. 6C) as usual, with two parallel rows of short setae on anterior and posterior surfaces, and two long distal setae on operculum (op).

Lingyun Dong is a karst cave open to the public in the Wangchuan Scenic Area, which is about 500 meters long. Based on the unpigmented body and long antennae, S. megistus sp. nov. is considered a troglobite.

Holotype male (SCAU), China, Henan Province, Nanyang City, Neixiang County, Qiliping Town, Cave Tianxin Dong, 33°20′51.85′′N 111°52′56.84′′E, 300 m, 30.VII.2018, Chen Mengzhen and Zhang Yan leg. Paratypes: 1 male, 8 females (SCAU), same data as for holotype.

Differs from congeners mostly based on the following combination of characters: (1) penis much shorter than male coxae 2 (Fig. 7E); (2) male leg 7 strongly reduced, with a rather small coxal process and a very small telopodite (Fig. 7F); (3) anterior gonopod (Fig. 7G, H) with a very long coxal process carrying a much lower and narrow membranous lobe, outer margin with an obvious groove and (4) an extremely long and slender flagellum, higher than coxal process. — In addition, this new species differs from all other Skleroprotopus species analyzed in uncorrected p-distances ranging between 6.6% (compared to S. change sp. nov.) and 16.2% (compared to S. longissimus sp. nov.).

Figure 7. 

Skleroprotopus longiflagellatus sp. nov.. A, D–I male paratype; B, C female paratype. A, B gnathochilarium; C left vulva, lateral view; D legs 1, anterior view; E legs 2 with penis, posterior view; F legs 7, anterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view. Abbreviations: cp, coxal process; cx, coxa; f, flagella; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The specific epithet refers to the anterior gonopod flagellum being particularly long; adjective.

Length of males ca 24.0–28.5 mm, 1.7–1.8 mm in diameter, body with 47–59 podous + 1–2 apodous rings + telson. Length of females ca 30.0–37.0 mm, height 1.8–2.0 mm in diameter, body with 57–66 podous + 1 apodous rings + telson. Coloration in alcohol (Fig. 3B) uniformly dark brown, prozona dark brownish, metazona yellow. Antennae and legs brownish. Eye patches blackish, subtriangular, arranged in 5–7 irregular rows, altogether about 25–55 ommatidia per eye patchr.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with about 26 setae in the first row and 4 setae in the second row. Antennae of medium length, reaching behind to anterior of ring 3 when stretched dorsally. In length, antennomeres 3>2>4>5>6>1>7. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded, more strongly rounded in females. Gnathochilarium with at least 4 setae on each lamella lingualis (ll); promentum (pr) lanceolate, swollen anteriorly in males (Fig. 7A), vs a drop-shaped pr in females (Fig. 7B).

Collum (Fig. 3B) with 5–7 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with 2–5 irregular subtransverse striae and metazona with 14–18 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites (Fig. 3B).

Epiproct (Fig. 3B) slightly protruding caudad, with 5+5 setae at posterior margin. Paraprocts convex, with 3+3 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs short, about 0.8× as long as midbody height. Male leg-pair 1 (Fig. 7D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest, about as long as all other telopoditomeres combined. Telopoditomere 4 (t4) irregularly shaped, mid-point slightly concave and with several long setae caudally. Male leg-pair 2 (Fig. 7E) reduced in size and slender; penis (pn) much shorter than coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 7F) strongly reduced, each leg with 1-segmented telopodite, setose apically; coxal process (cp) rather small, higher than telopodite, medial margin and distally densely setose.

Anterior gonopods (Fig. 7G, H) with a very long and narrow coxal process (cp) bearing a long row of short villi laterally, posteriorly carrying with a narrow, much lower membranous lobe (ml), outer margin of ml somewhat broadened, but smooth, with an obvious groove distally. Flagellum (f) extremely long and slender, slightly higher than cp, one side of distal part villose. Telopodite (te) about 3/5 as long as cp, with long setae both distally and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 7I) erect and slightly stout, clearly branched at tip, anterior branch smooth, with a pointed tip; posterior one densely setose.

Vulva (Fig. 7C) as usual, with two parallel rows of short setae on anterior and posterior surfaces, operculum (op) with long setae distally.

Tianxin Dong is also a sightseeing cave open to the public. Based on the pigmented body and legs, black eyes, as well as short legs, S. longiflagellatus sp. nov. is rather to be considered as a troglophile.

Holotype male (SCAU), China, Hubei Province, Xianning City, Xian’an District, Chang’e Scenic Park, Cave Feixian Dong, 29°43′56.29′′N 114°14′2.86′′E, 160 m, 13.VII.2019, Tian Mingyi, Cheng Jingli, Chen Mengzhen and Ma Zijun leg. Paratypes: 1 male, 4 females (SCAU), same data as for holotype.

Differs from congeners mostly based on the following combination of characters: (1) telopoditomere 4 of male leg 1 rounded, with a small mesal hump (Fig. 8E); (2) penis slightly longer than male coxae 2 (Fig. 8D); (3) male leg 7 with a very small coxal process and a 4-segmented telopodite (Fig. 8F); (4) anterior gonopod (Fig. 8G, H) with a very long coxal process carrying a somewhat broadened and dentated membranous lobe. — In addition, this new species differs from all other Skleroprotopus species analyzed in uncorrected p-distances ranging from between 6.6% (compared to S. longiflagellatus sp. nov.) and 15.6% (compared to S. longissimus sp. nov.).

Figure 8. 

Skleroprotopus change sp. nov.. A, D–I male paratype; B, C female paratype. A gnathochilarium and part of right antenna; B gnathochilarium; C right vulva, lateral view; D legs 2 with penis, posterior view; E legs 1, anterior view; F legs 7, anterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view. Abbreviations: cp, coxal process; cx, coxa; f, flagellum; h, hump; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The specific epithet is primarily derived from its type locality, which is named after Chang’e. She is the fairy of the moon palace in the ancient Chinese mythology. “Change” in Chinese “嫦娥”, a noun in apposition.

Length of both sexes ca 20.5–28 mm, width 1.7–1.8 mm, midbody height 1.5–1.8 mm, body with 48–56 podous + 1–2 apodous rings + telson. Natural coloration marbled reddish- to purple brownish (Fig. 2A). Anterior 2/3 body in alcohol yellowish brown, posterior 1/3 body yellowish. Antennae and legs pale yellowish (Fig. 3H). Eye patches blackish, subtriangular, arranged in 4–6 irregular rows, altogether about 15–30 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2(3)+2(3) supra-labral and 11+11 labral setae. Antennae of medium length, reaching behind to middle of ring 2 when stretched dorsally. In length, antennomeres 3≈2>6≈5>4>1>7. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded in males, more strongly rounded in females. Gnathochilarium with at least 5 setae on each lamella lingualis (ll); promentum (pr) lanceolate, slightly swollen anteriorly in males (Fig. 8A), vs a narrow drop-shaped pr in females (Fig. 8B).

Collum with 6–8 lower striae laterally, but lowest 2 striae not reaching the anterior margin (Fig. 3H). Prozona with 4 irregular subtransverse striae and metazona with 13–17 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites (Fig. 3H).

Epiproct slightly protruding caudad, laterally with 2+2 setae. Paraprocts convex, smooth. Hypoproct eye-shaped, with 1+1 setae.

Legs short, about 0.6× as long as midbody height, claw weakly curved, without modifications. Male leg-pair 1 (Fig. 8E) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest, about as long as all other telopoditomeres combined. Telopoditomere 4 (t4) irregularly shaped, with a small mesal hump (h) subapically; t3 and t4 with few scattered setae and short bristles on mesal face. Male leg-pair 2 (Fig. 8D) reduced in size and slender; penis (pn) unpaired, slightly longer than coxae (cx), cylindrical, distal part undulating, with five long setae. Male leg-pair 7 (Fig. 8F) strongly reduced, each leg with a 4-segmented asymmetrical telopodite (not including claw); coxal process (cp) small, densely setose.

Anterior gonopods (Fig. 8G, H) with a very long coxal process (cp) bearing two long rows of short villi in anterior view, posteriorly carrying with a membranous lobe (ml), outer margin of ml somewhat broadened, with small and irregular denticulations. Flagellum (f) very long and slightly thickened, distally villose. Telopodite (te) about half as long as cp, with long setae both distally and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 8I) erect, branched at tip, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulva (Fig. 8C) mostly wrapped inside a membrane, characteristic in shape, strongly elongated; operculum (op) longer than bursa, with two parallel rows of short setae on anterior face and 2 long setae distally.

This species inhabits Feixian Dong, a cave that is open to the public. Based on the pigmented body, black eyes, as well as very short legs, S. change sp. nov. is considered a troglophile.

Holotype male (SCAU), China, Anhui Province, Chizhou City, Shitai County, Gongxi Town, Cave Penglaixian Dong, 30°13′43.57′′N 117°32′7.44′′E, 100 m, 17.VII.2014, Tian Mingyi, Li Wenbo and Wu Yunhe leg. Paratypes: 12 males, 5 females (SCAU), same data as for holotype.

The name is derived from the overseas immortal mountains in Chinese mythology to emphasize the local cave harboring this species. “Penglai” in Chinese “蓬莱”, a noun in apposition.

Differs from congeners mostly based on the following combination of characters: (1) penis much shorter than coxae 2 (Fig. 9F); (2) male leg 7 with a very long coxal process and a rather small telopodite (Fig. 9C); (3) anterior gonopod (Fig. 9G, H) with a very long coxal process carrying a much lower, distally grooved membranous lobe, and a very long and thick flagellum. — In addition, this new species differs from all other species analyzed in a >10.1% uncorrected p-distance of the COI barcoding gene.

Figure 9. 

Skleroprotopus penglai sp. nov.. A, I female paratype; B–H male paratype. A, B gnathochilarium; C legs 7, anterior view; D legs 1, anterior view; E posterior gonopods, anterior view; F legs 2 with penis, posterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I left vulva, mesal view. Abbreviations: cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

Length of both sexes ca 20.0–36.5 mm, 1.5–1.9 mm in diameter, body with 50–62 podous + 1–3 apodous rings + telson. Coloration in alcohol (Fig. 3A) uniformly brown yellowish, prozona dark brownish, metazona yellow. Antennae and legs light yellowish. Eye patches blackish, subtriangular, arranged in 5–7 irregular rows, altogether about 22–39 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2(3)+2(3) supra-labral and 7+7 labral setae. Antennae of medium length, reaching behind to middle of ring 2 when stretched dorsally. In length, antennomeres 3>2>4>5>6>7>1. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes enlarged, with two faint lobes in males (Fig. 3A), rounded in females. Gnathochilarium with at least 6 setae on each lamella lingualis (ll); promentum (pr) lance-shaped at base, swollen anteriorly and olive-shaped in males (Fig. 9B), vs a conical pr in females (Fig. 9A).

Collum (Fig. 3A) with 9–11 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Dorsum with 5+5 short setae at rear edge of metatergites (Fig. 3A). Prozona with 2–4 irregular subtransverse striae and metazona with 15–23 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites (Fig. 3A).

Epiproct slightly protruding caudad, with 4+4 setae along posterior margin. Paraprocts convex, with 3+3 setae (Fig. 3A). Hypoproct eye-shaped, with 1+1 setae.

Legs long and slender, about 1.2× as long as midbody height. Male leg-pair 1 (Fig. 9D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest. Telopoditomere 4 (t4) irregularly shaped, mid-point slightly concave. Male leg-pair 2 (Fig. 9F) reduced in size and very slender; penis (pn) much shorter than coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 9C) strongly modified, with 2-segmented, rather small telopodites (te), telopoditomere 1 (t1) larger, with a few long setae subapically; coxal processes (cp) V-shaped, very long, densely setose.

Anterior gonopods (Fig. 9G, H) with a very long coxal process (cp) bearing a long row of short villi laterally, posteriorly carrying with a narrow, much lower, membranous lobe (ml), outer margin of ml somewhat broadened, but smooth, with an obvious groove distally. Flagellum (f) very long and thick, slightly shorter than cp, distally villose. Telopodite (te) about half as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 9E) erect, branched at tip, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulva (Fig. 9I) as usual, with two parallel rows of short setae on both anterior and posterior surfaces, operculum (op) with long setae distally.

Penglaixian Dong is also a limestone cave open to the public, with a total length of more than 3000 meters. It consists of four floors and is an interchange structure. Based on the unpigmented body and long legs, S. penglai sp. nov. is considered a troglobite.

Holotype male (SCAU), China, Hunan Province, Chenzhou City, Guidong County, Sidu Town, Cave Bidongfeiyan Dong, 26°0′13.32′′N 113°46′28.25′′E, 800 m, 19.X.2013, Tian Mingyi, Liu Weixin and Yin Haomin leg. Paratypes: 1 male, 5 females, 4 juveniles (SCAU), same data as for holotype; 7 males, 13 females, 1 juvenile, same cave, 4.IV.2021, Tian Mingyi and Cheng Jingli leg. Other material examined: 4 males, 5 females, 2 juveniles (SCAU), same county, Sidu Town, Cave Sidu Dong, 25°57′46.55′′N 113°47′07.33′′E, 900 m, VII.2011, Tian Mingyi, Gao Qi and Sun Feifei leg.

Differs from congeners mostly based on the following combination of characters: (1) penis much shorter than coxae 2 (Fig. 10E); (2) male leg-pair 7 with a rather long and slender coxal process (Fig. 10F); (3) anterior gonopod (Fig. 10G, H) with a very long coxal process carrying an irregularly dentate and membranous lobe, and a very long and slender flagellum. — In addition, this new species differs from all other species analyzed in a >12.4% uncorrected p-distance of the COI barcoding gene.

Figure 10. 

Skleroprotopus longissimus sp. nov.. paratypes from Cave Bidongfeiyan Dong. A, D–I male paratype; B, C female paratype. A, B gnathochilarium; C right vulva, mesal view; D legs 1, anterior view; E legs 2 with penis, posterior view; F legs 7, anterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view. Abbreviations: cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

Latin “longissimus” is meaning “the longest”. The specific epithet refers to the coxal process of male leg-pair 7 being particularly long and relatively slender; ajective.

Length of both sexes ca 25.0–40.0 mm, 1.6–1.9 mm in diameter, body with 47–54 podous + 1 apodous rings + telson. Natural coloration (Fig. 2C) red brownish, in alcohol uniformly brown yellowish, prozona dark brownish, metazona yellowish. Antennae and legs light yellowish. Eye patches blackish, subtriangular, arranged in 4–7 irregular rows, altogether about 20–37 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2(3)+2(3) supra-labral and 9+9 labral setae. Antennae of medium length, reaching behind to anterior of ring 3 when stretched dorsally. In length, antennomeres 3>2>4≈5>6>1>7. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded, with two small lobes in males, more rounded in females. Gnathochilarium with at least 4 setae on each lamella lingualis (ll); promentum (pr) relatively narrow, lance-shaped at base, swollen anteriorly and cup-shaped in males (Fig. 10A), vs a slightly broadened and oblong rhomboid pr in females (Fig. 10B).

Collum with 5–7 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with 4–6 irregular subtransverse striae and metazona with 11–25 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, with 4+4 setae at posterior margin. Paraprocts convex, with 2+2 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs long and slender, about 1.1× as long as midbody height. Male leg-pair 1 (Fig. 10D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest, about as long as all other telopoditomeres combined; Telopoditomere 4 (t4) irregularly shaped, with two vague emarginations, one lateral, the other dorsal. Male leg-pair 2 (Fig. 10E) reduced in size and very slender; penis (pn) shorter than coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 10F) strongly modified, coxal process (cp) extremely long and slender, crowned with a small hook facing anteriorly, strongly bent frontally, mostly subparallel-sided, considerably more slender, and free from setae along distal 2/3; telopodite (te) 1-segmented, rather small, carrying a long apical seta.

Anterior gonopods (Fig. 10G, H) with a medium length coxal process (cp), posteriorly carrying with an irregularly dentate membranous lobe (ml), outer margin of ml somewhat broadened and reflexed in proximal half, margin of reflexed part irregular. Flagellum (f) very long and slender, distally serrate and branched. Telopodite (te) about 3/4 as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 10I) erect, branched at tip, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulva (Fig. 10C) as usual, with two parallel rows of short setae on both anterior and posterior surfaces, operculum (op) with several long setae distally.

Sidu Karst is located in the Bamianshan National Nature Reserve, being the largest cave group found so far in southern Hunan. As the antennae and legs of this species are apparently slender and unpigmented, albeit the body retains some pigment, S. longissimus sp. nov. is considered a troglobite.

Holotype male (SCAU), China, Jiangxi Province, Ganzhou City, Chongyi County, Niedu Town, Cave Luohanyan, 25°27′9.03′′N 114°05′1.28′′E, 400 m, 9.XI.2014, fifteen graduate students from the class of 2013 leg. Paratypes: 28 males, 12 females (SCAU), same data as for holotype; 6 males, 6 females (SCAU), same cave, 12.I.2011, Tian Mingyi, Liu Weixin, Zheng Yuan and Sun Feifei leg. Other material examined: 4 males, 5 females (SCAU), same town, Cave Miao Dong, 25°28′1.62′′N 114°05′6.77′′E, 350 m, 13.I.2011, Tian Mingyi, Liu Weixin, Zheng Yuan and Sun Feifei leg.; 3 males (SCAU), same town, Cave Lianhua Dong, 25°28′10′′N, 114°05′37′′E, 400 m, 16.IV.2017, fifteen graduate students from the class of 2016 leg.

Differs from congeners mostly based on the following combination of characters: (1) penis much shorter than coxae 2 (Fig. 11E); (2) male leg 7 with an extremely long coxal process, strongly bent anteriad, telopodite rather small, 2 or 3-segmented (Fig. 11F); (3) anterior gonopod (Fig. 11G, H) with a coxal process of medium length and carrying a much lower, irregularly dentate, membranous lobe, and a very long and slender flagellum, distally branched. — In addition, this new species differs from all other species analyzed in a >8.2% uncorrected p-distance of the COI barcoding gene.

Figure 11. 

Skleroprotopus genjudi sp. nov.. paratypes from Cave Luohanyan. A, D–I male paratype; B, C female paratype. A, B gnathochilarium; C right vulva, mesal view; D legs 1, anterior view; E legs 2 with penis, posterior view; F legs 7, anterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view. Abbreviations: cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The species name is primarily derived from its collection site, which is often used as a place for our graduate students to conduct internships on cave biodiversity. “Genjudi” here refers to the main operational base, in Chinese is “根据地”; a noun in apposition.

Length of both sexes ca 30.0–42.0 mm, 1.7–2.1 mm in diameter, body with 51–63 podous + 1–2 apodous rings + telson. Natural coloration (Fig. 2D) uniformly grayish yellow. Antennae and legs light yellow. Eye patches grey to blackish, subtriangular, arranged in 4–7 irregular rows, altogether about 30–40 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 1(2)+1(2) supra-labral and 11+11 labral setae. Antennae long and slender, reaching behind to middle of ring 4 when stretched dorsally. In length, antennomeres 3>2>4>5>6>1>7. Antennomeres 5 and 6 each with distal corolla of sensilla basiconica. Antennomere 7 with 4 sensory cones. Mandibular stipes enlarged, with two small lobes in males, rounded in females. Gnathochilarium with at least 7 setae on each lamella lingualis (ll); promentum (pr) lance-shaped at base, swollen anteriorly, short and rod-like in males (Fig. 11A), vs a drop-shaped pr in females (Fig. 11B).

Collum with 4–6 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with 2–6 irregular subtransverse striae and metazona with 16–24 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, posterior margin with 3+3 setae. Paraprocts convex, with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs long and slender, about 1.2× as long as midbody height. Male leg-pair 1 (Fig. 11D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with several long setae. Telopoditomere 3 (t3) longest, about as long as all other telopoditomeres combined. Telopoditomere 4 (t4) irregularly shaped, with two vague emarginations, one lateral, the other dorsal. Male leg-pair 2 (Fig. 11E) reduced in size and slender; penis (pn) shorter than coxae (cx), distal part with five long setae. Male leg-pair 7 (Fig. 11F) strongly modified, coxal process (cp) extremely long, flattened dorsoventrally, only slightly attenuated distad, strongly bent anteriad, densely setose nearly throughout at both mesal and lateral margins; telopodite (te) remains poorly visible laterally near base of cp, vestigial, consisting of 2 or 3 very small telopoditomeres.

Anterior gonopods (Fig. 11G, H) with a coxal process (cp) of medium length, laterally bearing a long row of short villi, posteriorly carrying with a lower membranous lobe (ml), outer margin of ml irregularly dentate, somewhat broadened and reflexed in proximal half. Flagellum (f) very long and slender, distally serrate and branched. Telopodite (te) about 2/3 as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 11I) erect, with bristles medially, distally branched, anterior branch smooth and slender, with a pointed tip, posterior one densely setose.

Vulva (Fig. 11C) as usual, with two parallel rows of short setae on both anterior and posterior surfaces, operculum (op) with several long setae distally.

This new species was found in several caves at Niedu Town, Chouyi City, Jiangxi. Based on the unpigmented body, as well as long legs and antennae, S. genjudi sp. nov. is considered a troglobite.

Holotype male (SCAU), China, Jiangxi Province, Shangrao City, Wuyuan County, Cave Penghua Dong, 19.VII.2014, Tian Mingyi, Wu Yunhe and Li Wenbo leg. Paratypes: 34 males, 7 females (SCAU), same data as for holotype.

Differs from congeners mostly based on the following combination of characters: (1) male leg 1 relatively slender, telopoditomere 4 linguiform, with a small mesal hump (Fig. 12D); (2) penis much shorter than coxae 2 (Fig. 12F); (3) male leg 7 with a coxal process of medium size, densely setose at mesal margin, height subequal to telopodite, which is made up of 2 or 3 segements and a claw (Fig. 12E); (4) anterior gonopod (Fig. 12H, I) with a rather long coxal process carrying a narrow, lower, membranous lobe, distally with a vague indentation. — In addition, this new species differs from all other species analyzed in a >9.1% uncorrected p-distance of the COI barcoding gene.

Figure 12. 

Skleroprotopus ampullaceus sp. nov.. A, G female paratype; B–F, H–J male paratype. A, B gnathochilarium; C right antenna, lateral view; D legs 1, anterior view; E legs 7, anterior view; F legs 2 with penis, posterior view; G right vulva, mesal view; H anterior gonopods, anterior view; I anterior gonopods, posterior view; J posterior gonopods, anterior view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; f, flagella; h, hump; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

Latin “ampullaceus” is meaning bottle-shaped. The specific epithet refers to the the promentum of the gnathochilarium being bottle-shaped in males; adjective.

Length of both sexes ca 30.0–37.0 mm, 1.8–2.0 mm in diameter, body with 48–58 podous + 1–2 apodous rings + telson. Coloration in alcohol (Fig. 3D) uniformly yellow to dark brownish. Antennae and legs yellow brownish. Eye patches blackish, subtriangular, arranged in 4–6 irregular rows, altogether about 20–38 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2(3)+2(3) supra-labral and 9+9 labral setae. Antennae of medium length, reaching behind to middle of ring 2 when stretched dorsally. In length, antennomeres 3>4>2>5>6>1>7 (Fig. 12C). Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded, with two small lobes in male, rounded in female. Gnathochilarium with at least 5 setae on each lamella lingualis (ll); promentum (pr) lance-shaped at base, swollen anteriorly, bottle-shaped in males (Fig. 12B), vs a narrow, oblong, rhomboid pr in females (Fig. 12A).

Collum with 6–14 lower striae laterally, but lowest 4 striae not reaching the anterior margin. Prozona with 2–4 irregular subtransverse striae and metazona with 13–19 longitudinal striae laterally (Fig. 3D). Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, with 4+4 setae at posterior margin. Paraprocts convex, with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs short, but slender, about 0.9× as long as midbody height. Male leg-pair 1 (Fig. 12D) hypertrophied, relatively slender, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest, 1.5× as long as telopoditomere 4 (t4), t4 linguiform, with a small mesal hump (h) subapically; t3 and t4 with long setae medially. Male leg-pair 2 (Fig. 12F) reduced in size; penis (pn) fat, much shorter than coxae (cx), distal part with two long setae. Male leg-pair 7 (Fig. 12E) reduced, each leg with a 2 or 3-segmented asymmetrical telopodite (te) and a claw, telopoditomere 1 (t1) largest and setose subapically; coxal process (cp) medium-sized, about as high as te, densely setose at mesal margin.

Anterior gonopods (Fig. 12H, I) with a very long and relatively narrow coxal process (cp) bearing a long row of short villi laterally, posteriorly with a narrow, lower, membranous lobe (ml), outer margin of ml smooth, with a vague indentation distally. Flagellum (f) very long and slender, distally villose and branched. Telopodite (te) about half as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 12J) erect, with bristles medially, distally branched, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulva (Fig. 12G) as usual, with two parallel rows of short setae on both anterior and posterior surfaces, operculum (op) with several long setae distally.

Based on the pigmented body, black eyes, as well as moderately long legs and antennae, S. ampullaceus sp. nov. is considered a troglophile.

Holotype male (SCAU), Jiangxi Province, Shangrao City, Guangfeng County, Cave Lingjiu Dong, 28°27′54.12′′N 118°20′39.79′′, 200 m, 29.IX.2014, Huang Sunbin and Wang Xinhui leg. Paratypes: 2 males, 2 females (SCAU), same data as for holotype; 3 males, 7 females (SCAU), same county, Cave Tiangui Yan, 28°27′31.44′′N 118°16′57.70′′E, 200 m, 28.IX.2014; 1 male, 7 females (SCAU), Zhejiang Province, Jiangshan City, Dachen County, Cave Wulong Dong, 28°48′35.83′′N 118°34′59.37′′E, 300 m, 28.IX.2014, all Huang Sunbin and Wang Xinhui leg.

Differs from congeners mostly based on the following combination of characters: (1) telopoditomere 4 of male leg 1 with a small mesal hump (Fig. 13D); (2) penis slightly higher than coxae 2 (Fig. 13C); (3) male leg 7 with a very small coxal process, much lower than telopodite, which is made up of 4 segments and a claw (Fig. 13F); (4) anterior gonopod (Fig. 13E, I) with a very long coxal process carrying a narrow, lower, membranous lobe, distally with a vague indentation. — In addition, this new species differs from all other species analyzed in a >8.0% uncorrected p-distance of the COI barcoding gene.

Figure 13. 

Skleroprotopus incisodentatus sp. nov.. paratypes from Cave Lingjiu Dong. A, G female paratype; B–I male paratype. A, B gnathochilarium; C legs 2 with penis, posterior view; D legs 1, anterior view; E anterior gonopods, anterior view; F legs 7, anterior view; G vulvae, lateral view; H posterior gonopods, anterior view; I anterior gonopods, posterior view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; f, flagellum; h, hump; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The specific epithet refers to the distally vague indentation of a membranous lobe of anterior gonopod; adjective.

Length of both sexes ca 26.0–44.0 mm, 1.7–2.0 mm in diameter, body with 48–68 podous + 1–2 apodous rings + telson. Natural coloration (Fig. 2G) red brownish to purple brownish; generally yellow brownish in alcohol, prozona dark brownish. Antennae and legs yellow. Eye patches blackish, subtriangular, arranged in 6–8 irregular rows, altogether about 24–48 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 (Fig. 13B). Antennae long and slender, reaching behind to middle of ring 4 when stretched dorsally. In length, antennomeres 3>2>4≈5>4>6>7>1. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. (Fig. 13B). Mandibular stipes well-rounded, with two small lobes in males, regularly rounded in females. Gnathochilarium with at least 5 setae on each lamella lingualis (ll); promentum (pr) short and lanceolate, anteriorly swollen in males (Fig. 13B), vs a narrow rhombic pr in females (Fig. 13A).

Collum with 11–14 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with 2–3 irregular subtransverse striae and metazona with 16–25 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, with 3+3 setae laterally. Paraprocts convex, with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs medium-sized, about as long as midbody height. Male leg-pair 1 (Fig. 13D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some scattered long setae. Telopoditomere 3 (t3) longest, about 1.5× as long as telopoditomere 4 (t4), t4 irregularly shaped, subapically with a small mesal hump (h). Male leg-pair 2 (Fig. 13C) reduced in size; penis (pn) relatively thick, only slightly higher than coxae (cx), distal part with 3 long setae. Male leg-pair 7 (Fig. 13F) reduced, each leg with a 4-segmented telopodite (te) and a claw, telopoditomere 2 (t2) with a long seta subapically; coxal process (cp) small, median margin setose.

Anterior gonopods (Fig. 13E, I) with a very long coxal process (cp), bearing several short villi laterally, posteriorly carrying with a narrow, lower, membranous lobe (ml), outer margin of ml smooth, with a vague indentation distally. Flagellum (f) very long and slender, distally branched and villose. Telopodite (te) about 3/4 as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 13H) branched distally, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulvae (Fig. 13G) as usual, with two parallel rows of short setae on anterior and posterior surfaces, operculum (op) with several long setae distally.

This species was collected from two caves in the same county in Jiangxi Province, about 6 km apart. However, both are only about 40–50 km away from the collection site/cave in Zhejiang Province. Based on the pigmented body, black eyes, as well as moderately long legs, S. incisodentatus sp. nov. is considered a troglophile.

Holotype male (SCAU), China, Zhejiang Province, Hangzhou City, Jiande City, Cave Shenxian Dong, 29°23′27.83′′N 119°5′41.26′′E, 150 m, 27.XII.2018, Tian Mingyi, Cheng Jingli, Qin Zhuanghui and Chen Mengzhen leg. Paratypes: 22 males, 12 females (SCAU), same data as for holotype.

Differs from congeners mostly based on the following combination of characters: (1) collum with 10–16 lower striae and 18–27 longitudinal striae laterally on metazona (Fig. 3G). (2) telopoditomere 4 of male leg-pair 1 with two small mesal humps (Fig. 14D); (3) penis stout, distally sharpened, much shorter than coxae 2 (Fig. 14C); (4) male leg 7 with a very small coxal process, only slightly higher than 2-segmented telopodite (Fig. 14E); (5) anterior gonopod (Fig. 14G, H) with a very long and slender coxal process carrying a narrow, lower, membranous lobe, distally with a vague indentation. — In addition, this new species differs from all other Skleroprotopus species analyzed in uncorrected p-distances ranging from between 8.0–8.3% (compared to S. incisodentatus sp. nov.) and 14.6% (compared to S. longissimus sp. nov.).

Figure 14. 

Skleroprotopus multistriatus sp. nov.. A, J female paratype; B–I male paratype. A, B gnathochilarium; C leg 2 with penis, posterior view; D legs 1, anterior view; E legs 7, anterior view; F right antenna, lateral view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view; J right vulva, mesal view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; f, flagellum; h, hump; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The species is named after the more numerous striae on the collum and metazona; adjective.

Length of males ca 29.5–34.5 mm, 1.8–2.0 mm in diameter, body with 53–59 podous + 1 apodous rings + telson. Length of females ca 34.0–37.0 mm, 1.9–2.1 mm in diameter, body with 57–62 podous + 1–2 apodous rings + telson. Coloration in alcohol (Fig. 3G) generally marbled dark brownish, antennae and legs light brownish. Eye patches blackish, subtriangular, arranged in 4–6 irregular rows, altogether about 26–36 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2+2 supra-labral and 9+9 labral setae. Antennae long and slender, reaching behind to middle of ring 4 when stretched dorsally. In length, antennomeres 3>2>5>4>6>7>1 (Fig. 14F). Antennomeres 5 and 6 (Fig. 14F) each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded in male, even more strongly rounded in female. Gnathochilarium with at least 5 setae on each lamella lingualis (ll); promentum (pr) lute-shaped, anteriorly swollen and very narrow in males (Fig. 14B), vs a narrow, oblong and rhomboid pr in females (Fig. 14A).

Collum with 10–16 lower striae laterally, but lowest 4 striae not reaching the anterior margin. Prozona with 2–6 irregular subtransverse striae and metazona with 18–27 longitudinal striae laterally (Fig. 3G). Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, posterior margin with 4+4 setae. Paraprocts convex, with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs medium-sized, about as long as midbody height. Male leg-pair 1 (Fig. 14D) hypertrophied, 5-segmented, strongly curved anteriad; Coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some scattered long setae. Telopoditomere 3 (t3) longest, about 1.5× as long as telopoditomere 4 (t4), t4 irregularly shaped, caudally densely setose, subapically with two small mesal humps (h). Male leg-pair 2 (Fig. 14C) reduced in size and somewhat stout; coxae (cx) elongated, penis (pn) very stout, much shorter than cx, distal part sharpened, seta absent. Male leg-pair 7 (Fig. 14E) strongly reduced, each leg with a 2-segmented asymmetrical telopodite (te), telopoditomere 1 (t1) with several long setae; coxal process (cp) very small, slightly higher than te, medial margin and distally densely setose.

Anterior gonopods (Fig. 14G, H) with a very long and narrow coxal process (cp) bearing a row of short villi in anterior view, posteriorly carrying with a low, narrow, membranous lobe (ml), outer margin of ml smooth, with a vague indentation distally. Flagellum (f) very long and slender, distally branched and villose. Telopodite (te) about 2/3 as long as cp, with long setae at mesal margin and apically, laterobasally with a minute remnant (r) a second podomere.

Posterior gonopods (Fig. 14I) erect, branched distally, anterior branch smooth, with a very small and pointed tip, posterior one densely setose.

Vulva (Fig. 14J) as usual, with two parallel rows of short setae on both anterior and posterior surfaces; operculum (op) with 3 long distal setae.

Based on the pigmented body, black eyes, as well as moderately long legs, S. multistriatus sp. nov. is rather to be considered as a troglophile.

Holotype male (SCAU), China, Zhejiang Province, Jinhua City, Wucheng District, Cave Xianpu Dong, 29°12′23.04′′N 119°38′5.47′′E, 650 m, 28.XII.2018, Tian Mingyi, Cheng Jingli, Qin Zhuanghui and Chen Mengzhen leg. Paratypes: 8 males, 5 females (SCAU), same data as for holotype; 24 males, 34 females (SCAU), China, Zhejiang Province, Jinhua City, Lanxi City, Cave Baiyun Dong, 29°12′50.19′′N 119°32′28.62′′E, 300 m, 28.XII.2018, Tian Mingyi, Cheng Jingli, Qin Zhuanghui and Chen Mengzhen leg.

Differs from congeners mostly based on the following combination of characters: (1) telopoditomere 3 of male leg 1 longest, with a faint bulge in the middle (Fig. 15D); (2) penis very flat, much shorter than coxae 2 (Fig. 15E); (3) male leg 7 with a very small, cone-shaped coxal process and a basically normal telopodite (Fig. 15F); (4) anterior gonopod (Fig. 15G, H) with a very long coxal process carrying a narrow membranous lobe, outer margin distinctly serrate distally. — In addition, this new species differs from all other species analyzed in a >10.0% uncorrected p-distance of the COI barcoding gene.

Figure 15. 

Skleroprotopus conicus sp. nov.. paratypes from Cave Xianpu Dong. A, D-I male paratype; B, C female paratype. A, B gnathochilarium; C right vulva, mesal view; D legs 1, anterior view; E legs 2 with penis, posterior view; F legs 7, anterior view; G anterior gonopods, anterior view; H anterior gonopods, posterior view; I posterior gonopods, anterior view. Abbreviations: b, bulge; cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; r, remnant; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The specific epithet refers to the male leg 7 with a rather small and cone-shaped coxal process; adjective.

Length of both sexes ca 27.0–47.5 mm, width 1.8–2.0 mm in diameter, body with 55–68 podous + 1 apodous ring + telson. Coloration in alcohol uniformly brownish (Fig. 3E), prozona slightly red or dark brownish. Antennae and legs yellowish to light brown. Eye patches blackish, subtriangular, arranged in 6–14 irregular rows, altogether about 32–78 ommatidia per eye patch.

Head capsule smooth and hairless, vertex bulged, epicranial suture clearly concave. Labral margin with 2+2 supra-labral and 7+7 labral setae. Antennae long and slender, reaching behind to middle of ring 4 when stretched dorsally. In length, antennomeres 3>4>5>2≈6>7>1. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica. Mandibular stipes well-rounded, with two small lobes in males, rounded in females. Gnathochilarium with at least 3 setae on each lamella lingualis (ll); promentum (pr) short and lanceolate, swollen anteriorly, tube-shaped in males (Fig. 15A), vs an oblong rhomboid pr in females (Fig. 15B).

Collum (Fig. 3E) with 5–7 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona with at least 10 irregularly scattered striae and metazona with 13–18 longitudinal striae laterally (Fig. 3E). Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying anteriorly on lateral sides of metatergites.

Epiproct slightly protruding caudad, posterior margin with 2+2 setae. Paraprocts convex, medially with 1+1 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs medium-sized, about as long as midbody height. Male leg-pair 1 (Fig. 15D) hypertrophied, 5-segmented, strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with some long setae. Telopoditomere 3 (t3) longest, with a faint bulge (b) in the middle. Telopoditomere 4 (t4) irregularly shaped, with few setae medially. Male leg-pair 2 (Fig. 15E) reduced in size and stout; penis (pn) very flat, much shorter than coxae (cx), distal part with 6 long setae. Male leg-pair 7 (Fig. 15F) with a 4- or 5-segmented telopodite (te) sometimes asymmetrical (not including claw); coxal process (cp) rather small, cone-shaped, with few long setae apically.

Anterior gonopods (Fig. 15G, H) with a very long coxal process (cp) bearing a row of short villi in anterior view, posteriorly carrying with a narrow membranous lobe (ml), distal outer margin of ml distinctly serrate. Flagellum (f) very long and slender, with spikes at margin. Telopodite (te) about 3/4 as long as cp, with long setae both apically and mesally, laterobasally with a minute remnant (r) of a second podomere.

Posterior gonopods (Fig. 15I) erect, branched distally, anterior branch smooth, with a pointed tip, posterior one densely setose.

Vulva (Fig. 15C) as usual, with two parallel rows of short setae on anterior and posterior surfaces; operculum (op) with 2 long distal setae.

This species was collected from two caves in the same city, about 9 km apart. Based on the pigmented body, black eyes, as well as moderately long legs, S. conicus sp. nov. is rather to be considered as a troglophile.

Holotype male (SCAU), China, Fujian Province, Longyan City, Liancheng County, Laiyuan Town, Cave Chuqi Dong, 25°33′20′′N 116°59′51′′E, 950 m, 30.IV.2018, Tian Mingyi and Cheng Jingli leg. Paratypes: 7 males, 11 females (SCAU), same data as for holotype; 2 males, 11 females (SCAU), same location, Cave Shiyan Dong, 29.IV.2018; 3 males, 4 females (SCAU), same location, Cave Yanshang Dong, 30.IV.2018, all Tian Mingyi and Cheng Jingli leg.

Differs from congeners mostly based on the following combination of characters: (1) telopoditomere 3 of male leg-pair 1 extremely long, longer than all other telopoditomeres combined (Fig. 16D); (2) penis a little longer than coxae 2 (Fig. 16E); (3) male leg-pair 7 with very large coxal processes, about 4× as long as the telopodite (Fig. 16F); (4) anterior gonopod (Fig. 16H, I) with a very long coxal process carrying a narrow, lower, membranous lobe, outer margin distinctly microdentate; and an extremely slender flagellum. — In addition, this new species differs from all other species analyzed in a >10.8% uncorrected p-distance of the COI barcoding gene.

Figure 16. 

Skleroprotopus laiyuanensis sp. nov.. paratypes from Cave Chuqi Dong. A, G female paratype; B–F, H–J male paratype. A, B gnathochilarium; C right antenna, lateral view; D legs 1, anterior view; E legs 2 with penis, posterior view; F legs 7, anterior view; G left vulva, sublateral view; H anterior gonopods, anterior view; I anterior gonopods, posterior view; J posterior gonopods, anterior view. Abbreviations: a5, a6, antennomeres 5, 6; cp, coxal process; cx, coxa; f, flagellum; ll, lamella lingualis; ml, membranous lobe; op, operculum; pn, penis; pr, promentum; t1–t4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.

The species is named after its tye locality within the Laiyuan Karst Cave, which is the largest cave group known in Fujian Province, southeastern China; adjective.

Length of males ca 18.5–35.0 mm, 1.3–1.8 mm in diameter, body with 49–58 podous + 1 apodous rings + telson. Length of females ca 27.0–38.0 mm, 1.8 mm in diameter, body with 53–58 podous + 1 apodous rings + telson. Natural coloration (Fig. 2F) yellowish, in alcohol marbled brownish or red brownish. Antennae and legs yellowish. Eye patches blackish, subtriangular, arranged in 4–6 irregular rows, altogether about 22–43 ommatidia per eye patch.

Head capsule smooth and hairless, eyes slightly bulged, epicranial suture well-defined. Labral margin with 2(3)+2(3) supra-labral and 12+12 labral setae. Antennae very long and slender, reaching behind to middle of ring 5 when stretched dorsally. Antennomeres: 3>4>2≈5>6>1>7. Antennomeres 5 and 6 each with a distal corolla of sensilla basiconica (Fig. 16C). Mandibular stipes well-rounded, with two small lobes in males, regularly rounded in females. Gnathochilarium with at least 6 setae on each lamella lingualis (ll); promentum (pr) heart-shaped at base, the remainder swollen and fusiform in males (Fig. 16B), vs a narrow, oblong and rhomboid pr in females (Fig. 16A).

Collum with marbled brownish spots and 11 lower striae laterally, but lowest 2 striae not reaching the anterior margin. Prozona marbled, with 3–4 subtransverse striae and metazona with 20–23 longitudinal striae laterally. Suture dividing pro- and metazona very narrow, a regular comb. Ozopores starting with ring 6, lying mid-laterally on sides of metatergites.

Epiproct slightly protruding caudad, with 7+7 setae at posterior margin. Paraprocts convex, medially with 3+3 setae. Hypoproct eye-shaped, with 1+1 setae.

Legs medium-sized, about as long as midbody height. Male leg-pair 1 (Fig. 16D) hypertrophied, 5-segmented strongly curved anteriad; coxa (cx) and telopoditomeres 1 and 2 (t1, t2) with several long setae. Telopoditomere 3 (t3) longest, longer than all other telopoditomeres combined. Telopoditomere 4 (t4) irregularly shaped, medially with a few long setae. Male leg-pair 2 (Fig. 16E) reduced in size and rather slender; penis (pn) slightly longer than coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 16F) strongly modified, with a very small 2-segmented telopodite (te), telopoditomere 2 (t2) larger, with a few long setae subapically; coxal process (cp) about 4.0× as long as te, densely setose.

Anterior gonopods (Fig. 16H, I) with a very long coxal process (cp) bearing a short row of short villi in anterior view, posteriorly with a narrow and low membranous lobe (ml), outer margin of ml distinctly microdentate. Flagellum (f) very long and extremely slender, distally villose. Telopodite (te) about 2/3 as long as cp, densely setose apically and mesally.

Posterior gonopods (Fig. 16J) erect and slenderer, distally densely setose; anteriorly with a rather small pointed tip.

Vulva (Fig. 16G) as usual, with two parallel rows of short setae on both anterior and posterior surfaces. Operculum (op) subapically with three pairs of long setae, and two long distal setae on bursa.

This new species was found in several caves in Laiyuan Karst, which is the largest karst cave group found in eastern China (Fig. 17). Based on the unpigmented body and long antennae, S. laiyuanensis sp. nov. is rather to be considered as a troglobite.

Figure 17. 

A distribution map of the genus Skleroprotopus species in China. 1 Skleroprotopus laticoxalis; 2 S. confucius; 3 S. securifer; 4 S. membranipedalis; 5 S. serratus; 6 S. yutiantianae sp. nov.; 7 S. tiankeng sp. nov.; 8 S. megistus sp. nov.; 9 S. longiflagellatus sp. nov.; 10 S. change sp. nov.; 11 S. penglai sp. nov.; 12 S. multistriatus sp. nov.; 13 S. ampullaceus sp. nov.; 14 S. incisodentatus sp. nov.; 15 S. conicus sp. nov.; 16 S. longissimus sp. nov.; 17 S. genjudi sp. nov.; 18 S. laiyuanensis sp. nov. Abbreviations: BJ, Beijing.