Skleroprotopus penglai, Chen & Zhao & Golovatch & Liu, 2024

Chen, Rong, Zhao, Yi, Golovatch, Sergei & Liu, Wei-Xin, 2024, Molecular phylogenetic and morphological studies reveal increased species diversity in the millipede genus Skleroprotopus Attems, 1901 in China (Julida: Mongoliulidae), Arthropod Systematics & Phylogeny 82, pp. 659-691 : 659-691

3.3. 6. Skleroprotopus penglai sp. nov.

Figures 3 A , 9

Material examined.

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 .

Etymology.

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.

Diagnosis.

Differs from congeners mostly based on the following combination of characters: (1) penis much shorter than coxae 2 (Fig. 9 F ); (2) male leg 7 with a very long coxal process and a rather small telopodite (Fig. 9 C ); (3) anterior gonopod (Fig. 9 G, 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.

Description.

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. 3 A ) 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. 3 A ), 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. 9 B ), vs a conical pr in females (Fig. 9 A ).

Collum (Fig. 3 A ) 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. 3 A ). 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. 3 A ).

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

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

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

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

Remarks.

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.

Figures

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 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; t 1 – t 4, telopoditomeres 1–4; te, telopodite. Scale bars: 0.2 mm.