Epanerchodus chutou, Liu & Golovatch, 2018

Liu, Weixin & Golovatch, Sergei, 2018, The millipede genus Epanerchodus Attems, 1901 in continental China, with descriptions of seven new cavernicolous species (Diplopoda, Polydesmida, Polydesmidae), Zootaxa 4459 (1), pp. 53-84 : 71-72

Epanerchodus chutou , new species

Figs 14–15 .

Material examined: Holotype male ( SCAU eGZ12-1) from China, Guizhou Province, Shiqian County, Feng Dong Cave, 1.VIII.2015, colls: Mingyi Tian and Jingli Cheng . Paratype: 1 male ( SCAU eGZ12-2), same data as the holotype .

Diagnosis: Adult males of E. chutou n. sp. are distinct from other Epanerchodus species based on the following combination of characters: (1) body small (ca 15–16 mm long); (2) gonopodal telopodite falcate; (3) endomere hoe-shaped, folded at edge, with a slender, spiniform, basal process (a) and a short, digitiform, lateral process (p) at base ( Fig. 15 ).

This new species is similar to E. gladiatus n. sp. (from a cave in Guizhou, China) in the endomere showing a basal outgrowth and a missing exomere. However, E. chutou n. sp. is distinguished by the endomere being hoeshaped, with a slender, spiniform, basal process (a) ( Fig. 15 ) vs. endomere sword-shaped, with a small, rounded, ventral bump (a) in E. gladiatus n. sp. ( Fig. 13 ).

Description: Based on male type specimens. Lengths of body ca 16 (holotype) or 15 mm (paratype), widths of pro- and metazonae 1.2 and 2.0 mm (holotype), 1.1 and 2.0 mm (paratype). Coloration: generally nearly pallid to light yellowish in alcohol. Mouthparts and gonopodal telopodites grey-brownish. Body: Adults with 20 rings. Width: head <collum <ring 2 <3 <4 <5–14, thereafter body gradually tapering towards telson. Head: densely pilose, epicranial suture conspicuous ( Fig. 14B ). Antennae long, reaching behind posterior margin of ring 3 when extended posteriorly, slightly clavate. Exoskeleton: Collum fan-shaped, with a lateral incision on each side. Paraterga evident ( Fig. 14 ), midbody paraterga extend metatergite to ca 1.8x width of prozonite. Paraterga on collum and rings 2–4 clearly upturned dorsally above a faintly convex dorsum, other paraterga flat ( Fig. 14C ). Caudolateral corners of paraterga strongly acute and always projecting posteriorly past tergal margin ( Fig. 14A ). Integument shining, translucent, prozonae very delicately alveolate. Limbus regularly denticulate. Constriction between pro- and metazonae narrow, shallow and smooth. Metatergal sculpture faint, with three irregular transverse rows of setigerous, polygonal bosses. Sulcus between front and middle rows of setae a little deeper than that between middle and caudal rows. Tergal setae short, sometimes present only on collum and ring 2. Three or four faint setigerous incisions at lateral margins of poreless and pore-bearing rings, respectively. Pore formula normal: 5, 7, 9, 10, 12, 13, 15–19, ozopores evident, dorsal, clearly set off from lateral margin and located between last and penultimate marginal incisions. Epiproct short, conical, pre-apical lateral papillae small. Hypoproct subtrapeziform, with two setigerous papillae. Pleurosternal carinae absent. Sterna sparsely setose, cross-shaped impressions shallow. Legs long and slender, about 2.0 times as long as body ring height (male), without sphaerotrichomes or sternal cones, prefemora not bulging laterally. ( Fig. 14 ). Gonopods: ( Fig. 15 ) Coxa large. Telopodite falcate. Prefemur densely setose and robust, about 2/3 as long as telopodite. Clivus (cl) short. Endomere (en) hoe-shaped, folded at edge, with a slender, spiniform, basal process (a). A short, digitiform, lateral process (p) near en base. Seminal groove starting mesally, then recurving laterad to run into an accessory seminal chamber, the latter opening on a hairy pulvillus. An exomere absent.

Note: Due to the long slender antennae and legs, and a depigmented cuticle, this species is most likely a troglobite.

Etymology: To emphasize the gonopod resembling a hoe, in Chinese “ chutou ” (Ñẋ); noun in apposition.

Figures

FIGURE 13. Epanerchodus gladiatus n. sp., male paratype. A: left gonopod, mesal view. B: left gonopod, lateral view. Abbreviations: a = outgrowth; cl = clivus; en = endomere; p = process.

FIGURE 14. Epanerchodus chutou n. sp., male paratype. A–C: habitus, dorsal, ventral and lateral views. Scale bar: 0.2 mm.

FIGURE 15. Epanerchodus chutou n. sp., male paratype. A: right gonopod, lateral view. B: right gonopod, mesal view. Abbreviations: a = spiniform process; cl = clivus; en = endomere; p = process.