Epanerchodus xiaoxiensis Li, Deng & Liu, 2025

Epanerchodus xiaoxiensis Li, Deng & Liu sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Material examined.

Holotype. China: • ♂ (JSUXiaoxi 03); Hunan Province, Xiangxi Tujia and Miao Autonomous Prefecture, Yongshun County, Xiaoxi National Nature Reserve, Jinji Cave ; 28°46'48"N, 110°13'48"E, ca. 890 m a. s. l.; 12 August 2024, S. Li, H. J. Deng, Z. X. Liu, and Y. Tang leg. GoogleMaps Paratypes. China: • 3 ♂♂, 3 ♀♀ (JSUXiaoxi 04 - JSUXiaoxi 09); same data as holotype. GoogleMaps China: • 2 ♂♂, 4 ♀♀ (JSUXiaoxi 10 - JSUXiaoxi 15); same data as holotype; Hunan Province, Xiangxi Tujia and Miao Autonomous Prefecture, Yongshun County, Xiaoxi National Nature Reserve, Huangni Cave ; 28°48'57"N, 110°14'19"E, ca. 31043 m a. s. l.; 4 May 2023, H. J. Deng, Q. J. Wu, D. Q. Xiang, and Z. X. Liu leg. GoogleMaps China: • 5 ♂♂, 3 ♀♀ (JSUXiaoxi 16 - JSUXiaoxi 23); same data as holotype; Hunan Province, Zhangjiajie City, Cili County, Longwang Cave ; 29°26'27"N, 110°43'41"E, ca. 380 m a. s. l.; 21 September 2024, S. Li, Y. Z. Zou, Z. X. Liu, and Y. Tang leg. GoogleMaps

Etymology.

The specific name derives from the type locality, Xiaoxi National Nature Reserve. Adjective.

Diagnosis.

Adult males of E. xiaoxiensis sp. nov. are distinct from other Epanerchodus species based on the following combination of characters: (1) body smaller in size, length of body ca 11–13 mm (males), width of body ca 1.5–1.6 mm (males); (2) gonopodal prefemorite stout and short, about 1 / 3 as long as telopodite (Fig. 5 B View Figure 5 ); (3) gonopod endomere with a bifurcated shape at the end (Fig. 5 B View Figure 5 ); (4) gonopod exomere long and pointed, sword-shaped, as long as gonopod endomere (Fig. 5 B View Figure 5 ).

Diagnostic remarks.

Based both on the geographic distribution and morphological characters, the new species seems to be especially close to E. tujiaphilus ( Liu and Golovatch 2018) , from Longshan County, Hunan Province, in which the endomere tip is bifid and the exomere spiniform. However, the two species compared are clearly different: (1) body smaller and transparent white (Fig. 2 View Figure 2 ), vs. body larger and yellowish in E. tujiaphilus ; (2) the gonopod endomere is as long as the gonopod exomere (Fig. 5 A View Figure 5 ), vs. the gonopod endomere is considerably longer than the gonopod exomere.

Description.

Based on type specimens. Length of body ca 11–13 mm (males) or 12–15 mm (females). Width of body ca 1.5–1.6 mm (males) or 1.7–1.8 mm (females). Coloration: Live specimens semi-transparent to whitish (Fig. 2 View Figure 2 ); in alcohol, light yellowish (Fig. 3 View Figure 3 ). Body: Adults with 20 segments. In width, head <collum <segment 2 <3 <4 <5 <6 <7–16, thereafter body gradually tapering posteriorly towards telson. Head: vertex pubescent, epicranial suture conspicuous (Fig. 4 A View Figure 4 ), frons with dense short pubescence (Fig. 4 A View Figure 4 ). Labrum relatively flat and long, with a row of three sharp teeth (Fig. 4 A View Figure 4 ). Antennae long and slender, slightly clavate, densely setose, in situ extending past ring 4 when extended posteriorly (Fig. 3 B View Figure 3 ); in length, antennomere 7 <1 <4 = 5 <2 = 6 <3 (Fig. 4 B View Figure 4 ); antennomeres 5 and 6 each with a distodorsal group of sensilla basiconica (Fig. 4 B View Figure 4 ); antennomere 6 thick and swollen; antennomere 7 with four sensory cones apically (Fig. 4 C View Figure 4 ). Exoskeleton: Collum semi-oval, sparsely setose, with a lateral incision on each side (Figs 3 A View Figure 3 , 4 B View Figure 4 ). Paraterga well-developed and mostly slightly upturned dorsally (Fig. 4 D View Figure 4 ), midbody metaterga ca 1.6 times as wide as prozona (Fig. 3 A View Figure 3 ). Anterior margins of metaterga forming shoulders (Fig. 3 A View Figure 3 ). Caudolateral corners of paraterga starting with ring 2 clearly projecting posteriorly past tergal margin and strongly acuminate (Fig. 3 A View Figure 3 ). Integument shining, translucent, prozona very delicately alveolate (Fig. 3 A View Figure 3 ). Constriction between pro- and metazona narrow and smooth (Fig. 3 B View Figure 3 ). Metatergal sculpture faint, with three irregular transverse rows of setigerous polygonal bosses (Fig. 4 D View Figure 4 ). Sulcus between front and middle rows of setae distinct; that between middle and caudal rows obscure (Fig. 4 D View Figure 4 ). Tergal setae visible, short. Poreless and pore-bearing paraterga with 3 or 4 faint incisions at lateral margin, respectively. Ozopores located between last and penultimate marginal incisions (Fig. 4 D View Figure 4 ). Pore formula normal: 5, 7, 9, 10, 12, 13, 15–19. Epiproct process short, conical, slightly surpassing paraprocts caudally, pre-apical lateral papillae small, with two long setae (Fig. 4 F View Figure 4 ). Hypoproct trapezoid, with two setigerous, conical papillae at caudal margin (Fig. 4 F View Figure 4 ). Sterna sparely setose, cross-impressions shallow (Fig. 3 B View Figure 3 ). Rings 5–19 each with two pairs of long legs, tarsi longest, claws curved ventrad and pointed, legs ca 1.5 times as long as body height in both sexes. Neither sphaerotrichomes nor sternal cones, prefemora not bulged laterally (Fig. 4 E View Figure 4 ). Gonopods: coxite short and stout; prefemorite densely setose, as usual, about 1 / 3 as long as telopodite; femorite with a finger-shaped process (p); clivus (cl) short; endomere (en) with a bifurcated shape at the end; exomere (ex) long and pointed, sword-shaped, as long as endomere; seminal groove (sg) running mostly mesally, then ultimately entering an accessory seminal chamber (Fig. 5 View Figure 5 ).