Hyleoglomeris rukouqu, Liu, Weixin & Wynne, J. Judson, 2019

Liu, Weixin & Wynne, J. Judson, 2019, Cave millipede diversity with the description of six new species from Guangxi, China, Subterranean Biology 30, pp. 57-94 : 63-65

Hyleoglomeris rukouqu sp. nov. Figs 3A , 5 , 6

Type material.

Holotype male (SCAU), China, Guangxi Zhuang Autonomous Region, Yangshou County, Shangshuiyan Cave [24°57'43.6"N, 110°20'37.21"E], 191 m elevation (el.), cave entrance, ferns and other vegetation (refer to habitat section below), direct intuitive search, 17 November 2016, J.J. Wynne leg. Paratype, 1 female (SCAU), same data as holotype.

Etymology.

The species name, rukouqu, is used as a noun in apposition from the Mandarin phrase, rùkǒu qū (入口区). When translated to English it means "entrance zone" or "entrance area" to denote the area in the cave where this species was collected.

Diagnosis.

Adult male of H. rukouqu sp. nov. is distinct from other Hyleoglomeris species based on the following combination of characters: (1) peculiar color pattern ( Fig. 5 ); (2) telopods with a large, rectangular, central syncoxital lobe ( Fig. 6D ). This new species is similar to H. lii (a troglophile from a cave in Guangxi), but is distinguished by (1) 2+2 dark brown spots on the thoracic shield ( Fig. 5B, C ) vs. 1+1 light grey-yellow spots in H. lii ; (2) sycoxital lobe of telopods being high, large and rectangle-shaped ( Fig. 6D ) vs. low, linguiform, apically evidently concave in H. lii .

Description.

Based on type specimens. Length ca 8.0 mm (holotype), 11.0 mm (paratype), width 5.0 mm (holotype), 7.0 mm (paratype). Coloration: pattern vivid ( Fig. 3A ). With the exception of the brown dorsal spots, this species had similar coloration as that of the limestone rock and sediment within the entrance. General coloration in alcohol ( Fig. 5 ) light yellowish with contrastingly dark spots, latter absent on rings 3 and 11. Head only brownish caudal margin, antennae and ommatidia dark-brownish. Collum mostly marbled dark-brown except frontal margin part. Thoracic shield with 2+2 dark brown spots, but lateral ones smaller than middle ones. Terga 4 with 1+1 brownish spots, smaller than the above. Terga 5-7 and pygidium with 1+1 large, oblong, transverse, paramedian, marbled, dark spots. Terga 8-10, these paramedian spots increasingly separated into 2+2, but lateral ones smaller than middle ones. Head: Ommatidium at least 7+1, lenses rather convex. Tömösváry’s organ transverse-oval, parallel to the body, only slightly wider than long. Antennae with four apical cones, antennomere 6 ca 2.5 times as long as wide. Exoskeleton: Collum with two transverse striae ( Fig. 5C ). Thoracic shield ( Fig. 5B ) with a narrow hyposchism, the latter not reaching behind caudal tergal margin; 7 transverse striae: 3 starting below, 1 level to, 3 above schism; 5 striae (never the first and last from below) crossing the dorsum. Following terga 3-11 with two striae above lateral edge ( Fig. 5B ). Pygidium (last tergite) of both sexes slightly concave medially at caudal margin. ♂ leg 17 with a low, rounded, outer coxal lobe; telopodite 4-segmented ( Fig. 6A ). ♂ leg 18 with a subtrianglar syncoxital notch; telopodite 4-segmented ( Fig. 6B ). Telopods: ( Fig. 6 C–E ) with a large, subrectanglar, central syncoxital lobe flanked by high setose horns, each of the latter with a small lobe on top. Prefemur micropapillate laterally, with a long, digitiform, frontomesal trichostele. Femur with a smaller, digitiform, frontomesal trichostele. Caudomedial femoral process prominent, apically with an evident lobe. Tibia with a frontomesal seta. Caudomesal tibial process evident, recurved; an indistinct, papillate tubercle at base on caudal face. Tarsus strongly sigmoid, narrowly rounded apically.

Habitat.

Specimens were collected within a vegetation association that may be limited to the cave entrance zone and similar geographic features (e.g., sinkholes and fissures in rock). At least three plant species occurred within the entrance including Gesneriaceae sp., Adiantum sp., and one other fern species, which cannot be identified without examining the sorii (A. Monro, pers. comm. 2018).

Notes.

Based on the vivid color pattern and well-developed ommatidia, as well as the location where it was detected within the cave, this animal represents an epigean species and may be functioning as an obligate troglophile (sensu Peck 1970). While it is likely H. rukouqu sp. nov. either occurred or still occurs in similar habitats on the surface, the importance of relict plant species restricted to cave entrances has been discussed for southern China ( Monro et al. 2018). Additionally, several arthropod species globally are restricted to cave entrances in Polynesia ( Mockford and Wynne 2013, Wynne et al. 2014, Bernard et al. 2015, Taiti and Wynne 2015) and North America ( Benedict 1979, Wynne and Shear 2016) due to either extensive surface disturbance and glacial interglacial cycles, respectively. Thus, it is possible this species is a 'disturbance relict’ restricted to the entrance of Shangshuiyan Cave and potentially other area cave entrances with similar vegetation.

Figures

Figure 3. A Hyleoglomeris rukouqu sp. nov. from Shangshuiyan Cave B Hyleoglomeris xuxiakei sp. nov. from Guanshan No. 4 Cave C Hylomus yuani sp. nov. from Liangfeng Cave D Eutrichodesmus jianjia sp. nov. from Guanshan No. 4 Cave.

Figure 5. Hyleoglomeris rukouqu sp. nov., holotype. A-C Habitus, dorsal, lateral and ventral views, respectively.

Figure 6. Hyleoglomeris rukouqu sp. nov., holotype. A leg 17, anterior view B leg 18; anterior view C right half of telopods, posterior view D right half of telopods, anterior views E tip of syncoxital horn, anterior view.