Epanerchodus coniger, 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 : 63-65

Epanerchodus coniger , new species

Figs 8–9 .

Material examined: Holotype male ( SCAU eGZ6-1) from China, Guizhou Province, Bijie City, Zhijin County, Chengguan Town , Dongshan Village , Houshan Dong Cave , 12.VII.2013, colls: Mingyi Tian , Weixin Liu , Haomin Yin and Sunbin Huang . Paratypes: 1 male, 1 female ( SCAU eGZ6-1), same data as the holotype .

Diagnosis: Adult males of E. coniger n. sp. are distinct from other Epanerchodus species based on the following combination of characters: (1) sterna with a sharp cone near each coxa ( Fig. 8E ); (2) gonopod simple, with its clivus (a ridge on femorite) being very short and rounded; (3) endomere with a very small, nubbin-shaped, lateral, parabasal process and with two subapical denticles ( Fig. 9 ).

The former character is similar to that observed in E. soror (from caves in Yunnan, China). However, E. coniger n. sp. is distinguished by the head being narrower than the collum ( Fig. 8A ) vs. head broader than collum in E. soror ( Fig. 20A ).

Description: Based on type specimens. Lengths of body ca 20 mm (males) or 22 mm (female), widths of pro- and metazonae 1.3 and 2.3 mm (males) or 1.8 and 2.6 mm (female). Coloration: in alcohol generally nearly pallid to light yellow-brownish. Mouthparts light grey-brown and gonopodal telopodites yellowish. Body: Adults with 20 rings. Width: head <collum <rings 2–4 <5 <6 <7–16, thereafter body gradually tapering posteriorly towards telson. Head: densely pilose, epicranial suture conspicuous ( Fig. 8B ). Antennae long, reaching past anterior margin of ring 4 when extended posteriorly, slightly clavate ( Figs 8A–B ). Exoskeleton: Collum fan-shaped, with a lateral incision on each side. Paraterga evident ( Figs 8A–E ), midbody paraterga extend metatergite to ca 1.6x width of prozonite. Paraterga on collum, rings 2–8 and 16–18 clearly upturned dorsally above a faintly convex dorsum, other paraterga flat. Caudolateral corners of paraterga strongly acute, always projecting posteriorly past tergal margin ( Figs 8A, C, D ). Anterior margin of metaterga broadered in posterior part of body, forming a shoulder ( Figs 8A, C, D ). Integument shining, translucent, prozonae very delicately alveolate. Limbus regularly denticulate. Constriction between pro- and metazonae evident, broad and smooth ( Fig. 8C ). 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 mostly visible, short. 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, located between last and penultimate marginal incisions. Epiproct tip slightly concave, pre-apical lateral papillae evident ( Figs 8D–E ). Hypoproct subtrapeziform, with two setigerous papillae. Pleurosternal carinae small, present only on rings 2 and 3. Sterna sparsely setose, cross-shaped impressions shallow, with a small, but evident, sharp cone located mesocaudally to each coxa in both sexes, cones being slightly longer near posterior coxae ( Fig. 8E ). Legs long and slender ( Figs 8D–E ), about 2.0 times as long as body ring height in both sexes, devoid of sphaerotrichomes, prefemora not bulging laterally. Gonopods: simple ( Figs 8F , 9 ). Telopodite subfalcate. Prefemur densely setose and robust, about 2/3 as long as telopodite. Clivus (cl) very short and rounded. Endomere (en) at base with a very small, nubbin-like, lateral process (p). Tip of en sharp, with two subapical denticles on dorsal side. 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: Based on the long and slender antennae and legs, and a depigmented cuticle, this species is most likely a troglobite.

Etymology: To emphasize the sterna showing a sharp cone near each coxa; noun in apposition.

Figures

FIGURE 8. Epanerchodus coniger n. sp., male paratype. A: anterior part of body, dorsal view. B: anterior part of body, ventral view. C: midbody rings, dorsal view. D: posterior part of body, dorsal view. E: posterior part of body, ventral view. F: gonopods in situ, ventral view. Scale bar: A–E, 0.2 mm; F, no scale.

FIGURE 9. Epanerchodus coniger n. sp., male paratype. A: left gonopod, mesal view. B: left gonopod, lateral view. Abbreviations: cl = clivus; en = endomere; p = process.

FIGURE 20. Epanerchodus soror Geoffroy and Golovatch, 2004, male from Hama Dong Cave. A–C: habitus, ventral, subdorsal and lateral views. Scale bar: 0.2 mm.