A new species of the Clubionacorticalis-group (Araneae, Clubionidae) from Jiugong Mountains, Hubei Province, central China

Abstract Background The corticalis group is one of most diverse species-group in genus Clubiona Latreille, 1804. Currently, a total of 81 corticalis group species are known worldwide, amongst them 67 were recorded from China. However, the diversity of this group in China is still insufficiently known. New information Clubionaxianning sp. nov. is described as a new species of the C.corticalis species-group collected from Hubei Province, China.


Introduction
Clubiona Latreille, 1804 currently contains 518 catalogued species that are found worldwide, except for the Polar Regions and South America (World Spider Catalog 2022), is the most diverse genus in the family Clubionidae and one of the most diverse genera in the order Araneae (Zhang and Yu 2020, Zhang et al. 2021, World Spider Catalog 2022. One of the generic species-groups, the C. corticalis-group, exhibits high species diversity and currently contains 81 species (Zhang et al. 2021). Up to now, there are 67 described corticalis group species distributed in China, making it one of the most diverse clubionid groups in China (Zhang et al. 2021). However, the diversity of this group in China is still insufficiently known and several new species have been described in the last few years (Zhang et al. 2018, Yu and Li 2019a, Yu and Li 2019b, Zhang and Yu 2020, Zhang et al. 2021. While examining spiders collected from Jiugong Mountains, Hubei Province, China (Fig. 1), we found pairs of Clubiona specimens that belong to an undescribed species of the corticalis-group similar to C. caohai Yu, 2020 andC. altissimus Hu, 2001. The goal of this paper is to provide a detailed description and diagnosis of the new species. The DNA barcodes of the new species were obtained for gender matching and future use in molecular studies.

Materials and methods
Specimens in this study were collected by hand collecting from leaf-litter in Mt. Jiugong, Hubei. Spiders were fixed and preserved in 95% ethanol. Specimens were examined with an Olympus SZX7 stereomicroscope; details were studied with an Olympus CX41 compound microscope. Female epigyne and male palp were examined and illustrated after being dissected. The epigyne was removed and cleared in warm lactic acid before illustration. The vulva was also imaged after being embedded in Arabic gum. Photos were made with a Cannon EOS70D digital camera mounted on an Olympus CX41 compound microscope. The digital images were taken and assembled using Helifocus 6.80 software package. The distribution map was generated with Arcgis 10.5 (Environmental Systems Research Institute, Inc.). Clubiona xianning sp. nov., male holotype (A, B) and female paratype (C), live specimens. Photographs by Qianle Lu (Shenzhen, Guangdong).
A DNA barcode was also obtained for species matching. A partial fragment of the mitochondrial cytochrome oxidase subunit I (CO1) gene was amplified and sequenced for two specimens, using the primers LCOI1490 (5'-GGTCAACAAATCATAAAGATATTG-3') and HCOI2198 (5'-TAAACTTCAGGGTGACCAAAAAAT-3') (Folmer et al. 1994). For additional information on extraction, amplification and sequencing procedures, see Wheeler et al. (2016). DNA sequences were checked and edited with BioEdit 7.2.2 (Hall 1999), sequences being trimmed to 653 bp. Sequence alignment was completed using CLUSTAL W (Thompson et al. 1994). Genetic distances were computed with MEGA 5 (Tamura et al. 2011). All sequences were confirmed using BLAST and are deposited in GenBank. The codes and GenBank accession numbers of voucher specimens are provided as follows: YHCLU0272, ♂, GenBank OP675437; YHCLU0273, ♀, GenBank OP675436.
All measurements were obtained using an Olympus SZX7 stereomicroscope and given in millimetres. Eye diameters are taken at the widest point. The total body length does not include chelicerae or spinnerets length. Leg lengths are given as total length (femur, patella, tibia + metatarsus, tarsus). Most of the terminologies used in text and figure legends follows Zhang et al. (2021), while a few others followed Zhang et al. (2018) and Zhang and Yu (2020).
Abdomen ( Fig. 4E and F) oval and light brown, dorsally with a wide and more or less oblong scutum extending ca. 2/3 of abdomen length, with two pairs of inconspicuous muscle depressions on either side; venter white with no distinct pattern; spinnerets yellowish-white.
Legs uniformly yellowish-white in ethanol ( Fig. 4E and F Palp (Fig. 3A-E). Femur and patella unmodified. Tibia relatively short, about 2/5 of cymbium length, with two apophyses: a retrolateral one (RTA) that is heavily sclerotised, ca. 1/2 of palpal tibia length, more or less blade-shaped; a partly membranous, laminar apophysis (VTA), ca. 1/3 of palpal tibia length. Bulb nearly pyriform, slightly excavated on prolatero-apical side to accommodate embolus; tegulum oval and slightly expanded, ca. 1.45 longer than wide, sperm duct indistinct in venter view; subtegulum (ST) large, located prolaterally. Embolus (E) wide and heavily sclerotised, about 2/3 of the tegulum length, dagger-shaped, gradually tapering towards its apex, its tip sharp, slightly curved and extending to apex of cymbium. Conductor long and membranous, irregular-shaped in venter view and triangular in retrolateral view, its tip extending above apex of embolus.

Etymology
The specific name refers to the type locality and is a noun in apposition.