Desmoxytes laticollis, Liu, Weixin, Golovatch, Sergei & Tian, Mingyi, 2016

Liu, Weixin, Golovatch, Sergei & Tian, Mingyi, 2016, Six new species of dragon millipedes, genus Desmoxytes Chamberlin, 1923, mostly from caves in China (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 577, pp. 1-24 : 3-4

Taxon classification Animalia Polydesmida Paradoxosomatidae

Desmoxytes laticollis sp. n. Figs 1 A–B, 2, 3

Holotype

♂ (SCAU), China, Guangdong, Qingyuan, Yingde Shi, Huanghua Xiang, Yanbei Cun, Cave Yangyan Dong, 24°18'32"N, 112°47'20"E, ca 450 m a.s.l., 2014-XII-30, leg. Mingyi Tian, Weixin Liu, Sunbin Huang & Xinhui Wang.

Paratypes.

13 ♂, 7 ♀ (SCAU), 1 ♂, 1 ♀ (ZMUM), 1 ♂, 1 ♀ (ZFMK), same locality and collecting data as the holotype.

Name.

To emphasize the collum being the broadest segment; adjective.

Diagnosis.

Keys out to the superficially most similar Desmoxytes eupterygota Golovatch, Li, Liu & Geoffroy, 2012 ( Liu et al. 2014), especially so concerning metatergal ornamentation and a condensed solenophore, but differs by the collum being the broadest segment, as well as the femora, postfemora and tibiae conspicuously clavate in both sexes.

Description.

Length ca 26-27 mm (♂) or 28-29 mm (♀), width of midbody pro- and metazonae 2.0 and 2.5 (♂) or 2.2 and 2.5 mm (♀), respectively. Holotype 26 mm long, 2.0 and 2.5 mm wide on midbody pro- and metazonae, respectively, maximum width on collum 3.5 mm. In width, head <segment 8-16 <5-7 <4 <3 <2 <collum; starting with segment 17, body gradually tapering towards telson (Fig. 2). Live coloration rather uniformly yellowish to pallid (Fig. 1 A–B). Head sparsely setose, epicranial suture distinct (Fig. 2 A–B). Antennae long and slender, reaching back until posterior margin of segment 5 (♂) or middle of segment 4 (♀) when stretched dorsally; antennomeres 5 and 6 each with a compact apicodorsal group of bacilliform sensilla.

Body with 20 segments. Tegument (Fig. 2) very strongly shining, prozonae faintly microalveolate; surface below paraterga of collum and those of segments 2-4 finely microgranulate. Collum (Figs 2A, 3A) with at least 2+2 setae at front margin, another 1+1 setae in the middle, hardly visible; paraterga on collum particularly strongly developed, wing-shaped, lying a little below a rather convex collum; paraterga on segments 2-4 clearly elevated above dorsum, thereafter rather poorly-developed, relatively small and crest-shaped, lying slightly below level of a faintly convex dorsum until segment 18, vestigial and lying far below level of a strongly convex dorsum on segment 19 (Fig. 2A, C, E); paraterga 1-4 with three especially strong denticles at lateral margin, two anterior of the denticles gradually disappearing towards segment 7, but caudalmost tooth persisting until segment 18 (Fig. 2A, C, E). Metaterga 2-4 each with 1+1 setae in anterior row; each of metaterga 5-19 additionally with 1+1 setae in posterior row, mostly poorly visible; paraterga a little more strongly developed in ♂ than in ♀, calluses very thin in poreless segments, slightly thicker in pore-bearing ones. Stricture between pro- and metazonae very narrow and deep. Ozopores entirely lateral, lying on top of caudal tooth on pore-bearing paraterga (Fig. 2A, C, E). Transverse sulcus evident and deep, smooth at bottom, reaching bases of paraterga on segments 7-16, incomplete (not reaching the bases of paraterga) in segments 5-6 and 17-18, vestigial in segment 19 (Fig. 2A, C, E). Epiproct subconical, clearly flattened dorsoventrally, mostly broad, subtruncate at a narrow apex, subapical lateral setae not borne on knobs (Fig. 2 E–F). Hypoproct subtrapeziform, clearly emarginate at caudal margin, caudal setae distinctly separated (Fig. 2 E–F). Pleurosternal carinae poorly-developed, only visible on segments 2 and 3 both in ♂ and ♀. Axial line missing.

Sterna sparsely setose, nearly flat, cross-impressions shallow, axial groove being especially superficial (Fig. 2B, D, F). A pair of paramedian, densely setose, low cones between ♂ coxae 4 (Figs 2B, 3B). Legs 1 short, following ones growing slightly, but increasingly long and slender towards telson, midbody legs ca 2.5 (♂) or 2.0 (♀) times as long as body height; femora, postfemora and tibiae conspicuously clavate distad, neither tarsal brushes nor adenostyles in ♂ and ♀ (Fig. 2).

Gonopods (Fig. 3 C–D) suberect. Coxite short, subcylindrical, sparsely setose distodorsally, nearly 1/3 as long as telopodite. Prefemur densely setose, almost half as long as acropodite. Femorite long, slightly curved ventrad. Solenophore (sph) clearly condensed and divided into a large rectangular lobe on lateral side (= lamella lateralis, ll) and a distinct coiled part on mesal side (= lamella medialis, lm). Seminal groove running entirely on mesal side of femorite before entering onto a short, but evident and flagelliform solenomere (sl), the latter lying between ll and lm.

Remark.

Because of the pallid tegument and remarkably elongated antennae and legs, this species is most probably a troglobite.