Epanerchodus tujiaphilus, 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 : 59-61

Epanerchodus tujiaphilus , new species

Figs 3–4 .

Material examined: Holotype male ( SCAU eHN2-1) from China, Hunan Province, Longshan County, Huoyan Village, Tujiamei Dong Cave , 2.VII.2014, colls: Mingyi Tian, Weixin Liu, Haomin Yin, Sunbin Huang and Xinhui Wang . Paratypes: 4 males, 9 females ( SCAU eHN2-2), same data as the holotype . 2 males ( SCAU eHN3-1) same data as the holotype, but from different cave: Wulong Dong Cave ; 7 males, 14 females (SCAU eHN4-1), 1 male, 1 female ( ZMUM), same data as the holotype, but from different cave: Panlong Dong Cave ; 3.VII.2014, colls: Mingyi Tian, Weixin Liu, Haomin Yin, Sunbin Huang and Xinhui Wang . 3 males ( SCAU eHN5-1) same data as the holotype, but from different cave: Feng Dong Cave , 30.VI.2015, colls: Mingyi Tian, Weixin Liu, Xinhui Wang and Mingruo Tang.

Diagnosis: Adult males of E. tujiaphiulus n. sp. are distinct from other Epanerchodus species based on the following combination of characters: (1) caudolateral corners of paraterga posterior to collum strongly acute ( Fig. 3A–E ); (2) gonopodal prefemur robust, about 2/3 as long as telopodite; (3) endomere tip unequally bifid; (4) exomere long and spiniform ( Fig. 4 ).

The new species is close to E. varius (from caves in Sichuan, Hubei and Chongqing, China), but is distinguished by (1) the strongly reduced gonopodal femorite devoid of any outgrowths ( Fig. 4A ) vs. with a spine in E. varius ( Fig. 25 ); (2) gonopod with a clearly longer exomere and a broader endomere ( Fig. 4 ) vs. a much shorter exomere and a slenderer endomere in E. varius ( Fig. 25 ).

Description: Based on type specimens. Lengths of body ca 18–22 mm (males) or 20–28 mm (females), widths of pro- and metazonae 1.5–1.8 and 2.8–3.2 mm (males) or 1.6–2.0 and 3.0– 3.2 mm (females). Coloration: in alcohol nearly pallid to light yellowish. Mouthparts light grey-brown, gonopodal telopodites yellowish. Body: Adults with 20 rings. Width: head << collum <ring 2 <3 <4 <5–13, thereafter body gradually tapering posteriorly towards telson. Head: densely pilose, epicranial suture conspicuous ( Fig. 3C ). Antennae long and slender, reaching past anterior margin of ring 4 when extended posteriorly, slightly clavate ( Figs 3B–C ). Exoskeleton: Collum transversely semi-lunar, with an evident lateral incision on each side ( Fig. 3C ). Paraterga evident ( Fig. 3A–C ), midbody paraterga extend metatergite to ca 1.8x width of prozonite. Paraterga 2–7 clearly upturned dorsally above a faintly convex dorsum, other paraterga flat ( Fig. 3B ). Caudolateral corners of paraterga posterior to collum strongly acute, clearly projecting posteriorly past tergal margin. Anterior margin of metaterga bordered and forming a distinct shoulder ( Figs 3A–E ). Integument shining, translucent, prozonae very delicately alveolate. Limbus regularly denticulate. Constriction between pro- and metazonae broad and smooth ( Figs 3A–D ). 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 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 and located between last and penultimate marginal incisions. Epiproct long, tip concave, pre-apical lateral papillae evident ( Figs 3D–E ). Hypoproct subtrapeziform, with two setigerous papillae. Pleurosternal carinae absent. Sterna sparsely setose, cross-shaped impressions shallow ( Fig. 3C ). Legs long and slender, about 2.0–2.2 times as long as body ring height in both sexes, without sphaerotrichomes or sternal cones, prefemora not bulging laterally ( Fig. 3C ). Gonopods: subfalcate ( Figs 3F , 4A–B ). Prefemur densely setose and robust, about 2/3 as long as telopodite. Femorite strikingly short, about 1/5 as long as telopodite. Endomere (en) ribbon-shaped, tip unequally bifid, longest branch only slightly longer than a spiniform, simple exomere (ex). A single, prominent, digitiform process (p) at base of, and about half as long as, endomere. Seminal groove (sg) starting mesally, recurved laterad at base of ex, then turning laterobasad to run into an accessory seminal chamber.

Note: Based on the long slender antennae and legs, and a depigmented cuticle, the species is most likely a troglobite.

Etymology: Derived from the local tribe Tujia (± ẎŔ) that populates the area and the Greek “philos”, meaning “liking”; masculine adjective.

Figures

FIGURE 3. Epanerchodus tujiaphilus n. sp., male paratype from Tujiamei Dong Cave. A–C: anterior part of body, dorsal, lateral and ventral views. D: posterior part of body, dorsal view. E: posterior part of body, lateral views. F: gonopods in situ, ventral view. Scale bar: A–E, 0.2 mm; F, no scale.

FIGURE 4. Epanerchodus tujiaphilus n. sp., male paratype from Tujiamei Dong Cave. A: left gonopod, mesal view. B: left gonopod, lateral view. Abbreviations: en = endomere; ex = exomere; p = process; sg = seminal groove.

FIGURE 25. Epanerchodus varius (Geoffroy and Golovatch, 2004), male from Zhakou Dong Cave. A: left gonopod, mesal view. B: right gonopod, lateral view. Abbreviations: en = endomere; ex = exomere; l = lobe; p = process; s = spine.