Skleroprotopus longiflagellatus, 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. 4. Skleroprotopus longiflagellatus sp. nov.

Figures 3 B , 7

Material examined.

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 .

Diagnosis.

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

Etymology.

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

Description.

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. 3 B ) 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. 7 A ), vs a drop-shaped pr in females (Fig. 7 B ).

Collum (Fig. 3 B ) 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. 3 B ).

Epiproct (Fig. 3 B ) 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. 7 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, about as long as all other telopoditomeres combined. Telopoditomere 4 (t 4) irregularly shaped, mid-point slightly concave and with several long setae caudally. Male leg-pair 2 (Fig. 7 E ) reduced in size and slender; penis (pn) much shorter than coxae (cx), distal part with three long setae. Male leg-pair 7 (Fig. 7 F ) 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. 7 G, 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. 7 I ) erect and slightly stout, clearly branched at tip, anterior branch smooth, with a pointed tip; posterior one densely setose.

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

Remarks.

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.

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