Eight new species of the spider genus Pimoa (Araneae, Pimoidae) from Tibet, China

Abstract Eight new species of the spider genus Pimoa Chamberlin & Ivie, 1943 are described from Tibet, China: P. cona Zhang & Li, sp. nov. (♂♀), P. duiba Zhang & Li, sp. nov. (♂♀), P. lemenba Zhang & Li, sp. nov. (♀), P. mainling Zhang & Li, sp. nov. (♂♀), P. nyingchi Zhang & Li, sp. nov. (♂♀), P. rongxar Zhang & Li, sp. nov. (♂♀), P. samyai Zhang & Li, sp. nov. (♂♀), and P. yadong Zhang & Li, sp. nov. (♂♀). The DNA barcodes of the eight new species are documented.


Materials and methods
Specimens were examined with a LEICA M205C stereomicroscope. Images were captured with an Olympus C7070 wide zoom digital camera (7.1 megapixels) mounted on an Olympus SZX12 dissecting microscope and assembled using Helicon Focus 3.10.3 image stacking software (Khmelik et al. 2006). Epigynes and male palps were examined after dissection from the spiders' bodies. The left palps were illustrated unless otherwise noted. Epigynes were removed and treated in a warmed 10% potassium hydroxide (KOH) solution.
All measurements were obtained using a LEICA M205C stereomicroscope and are given in millimeters. We put legs and the body of the spider on the objective table of stereomicroscope and measured the length by a ruler in the eyepiece. Eye sizes were measured as the maximum diameter from either dorsal or frontal views. Leg measurements are shown as total length (femur, patella + tibia, metatarsus, tarsus). The terminology used in the text and the figure legends follows Hormiga (1994a). Distribution maps were generated using ArcView GIS (ESRI) software.
Abbreviations used in this paper and in the figure legends: ALE anterior lateral eye; AME anterior median eye; AME-ALE distance between AME and ALE; AME-AME distance between AMEs; AS alveolar sclerite; C conductor; CDP cymbial denticulate process; CO copulatory opening; DP dorsal plate of the epigyne; E embolus; FD fertilization duct; MA median apophysis; P paracymbium; PCS pimoid cymbial sclerite; PEP pimoid embolic process; PLE posterior lateral eye; PME posterior median eye; PME-PLE distance between PME and PLE; PME-PME distance between PMEs; S spermatheca; T tegulum; VP ventral plate of epigyne.
DNA barcodes were obtained for the eight new species by amplifying and sequencing a partial fragment of the mitochondrial gene cytochrome oxidase subunit I (COI) using primers LCO1490-oono (5'-CWACAAAYCATARRGATATTGG-3') (Folmer et al. 1994;Miller et al. 2010) and HCO2198-zz (5'-TAAACTTCCAGGTGAC-CAAAAAATCA-3') (Folmer et al. 1994;Zhao and Li 2017). For additional information on extraction, amplification, and sequencing procedures, see Wang et al. (2008). All sequences were checked for validity using BLAST and are deposited in GenBank. The accession numbers are provided in Table 1.

Figure 2.
Epigyne and habitus of Pimoa cona sp. nov., female paratype and male holotype A epigyne, ventral view B schematic course of internal duct system, ventral view C vulva, dorsal view D schematic course of internal duct system, dorsal view E male habitus, dorsal view F female habitus, dorsal view G female habitus, ventral view. Abbreviations: CO = copulatory opening; DP = dorsal plate of the epigyne; FD = fertilization duct; S = spermatheca; VP = ventral plate of epigyne. Scale bars: equal for F and G. but can be distinguished by the pair of oval spermathecae ( Fig. 2A, vs. subtriangular spermathecae) and by the subdistally narrow dorsal plate (Fig. 2C, vs. subdistally wide).
Distribution. Known only from the type locality, Tibet, China (Fig. 16).  (Fig. 5A, vs. separated by ca. 1/2 the width of a spermatheca), by the medially wide dorsal plate (Fig. 5C, vs. medially relatively narrow), and by the abdomen with the vertical band not extending to the distal part (Fig. 5E, vs. vertical band absent).
Male: unknown. Distribution. Known only from the type locality, Tibet, China (Fig. 16). Etymology. The specific name is a noun in apposition taken from the type locality. Diagnosis. The male of Pimoa mainling sp. nov. resembles P. binchuanensis (see Zhang and Li 2019: 3, figs 1, 2) but can be distinguished by the distally curved and nearly hook-shaped pimoid cymbial sclerite (Fig. 6B, vs. medially curved and nearly  U-shaped). The male of P. mainling also resembles P. crispa Hormiga, 1994(see Hormiga 1994aHormiga 1994b: fig 1A, B) but can be distinguished by a distally narrow cymbial denticulate process with few cuspules (Fig. 6B, vs. distally wide cymbial denticulate process with many cuspules). The female of P. mainling resembles P. crispa Hormiga, 1994(see Hormiga 1994a: 63, figs 239-247) but can be distinguished by the distance between the pair of spermathecae which is ca. 1/3 the width of a spermatheca (Fig. 7A, vs. shorter distance between spermathecae) and by the funnelshaped epigyne, which is distally straight and long (Fig. 7A-D, vs. triangular epigyne).
Distribution. Known only from the type locality, Tibet, China (Fig. 16).  (Fig. 8B, vs. narrow and distally curved) and by the relatively large and wide paracymbium (Fig. 8B, C, vs. small and narrow). The female of P. nyingchi also resembles P. reniformis (see Xu and Li 2007: 493, figs 42-47) but can be distinguished by a pair of small, oval spermathecae (Fig. 9C, vs. large and kidneyshaped) and by the broad dorsal plate (Fig. 9C, vs. narrow dorsal plate).
Distribution. Known only from the type locality, Tibet, China (Fig. 16). Etymology. The specific name is a noun in apposition taken from the type locality. Diagnosis. The male of Pimoa rongxar sp. nov. resembles P. reniformis (see Xu and Li 2007: 493, figs 36-41) and P. thaleri Trotta, 2009(see Trotta 2009: 1404 fig. 1) but can be distinguished by the large, long and subdistally wide pimoid cymbial sclerite (Fig. 10B, vs. small and narrow in P. reniformis; vs. short and medially wide in P. thaleri); distinguished from P. reniformis by the long palpal tibia, ca. 1/2 of the cymbial length ( Fig. 10A-C, vs. palpal tibia short, ca. 1/3 of the cymbial length); distinguished from P. thaleri by the pimoid embolic process which is longer than the embolus (Fig.  10B, vs. a pimoid embolic process that is almost the same length as the embolus). The female of P. rongxar resembles P. indiscreta Hormiga, 1994(see Hormiga 1994a but can be distinguished by a pair of nearly round spermathecae (Fig. 11A, vs. nearly oval) and by the laterally oriented pair of fertilization ducts ( Fig.  11A-D, vs. medially oriented fertilization ducts).
Distribution. Known only from the type locality, Tibet, China (Fig. 16).  Etymology. The specific name is a noun in apposition taken from the type locality. Diagnosis. The male of Pimoa samyai sp. nov. resembles P. binchuanensis (see Zhang and Li 2019: 3, figs 1, 2) and P. crispa Hormiga, 1994(see Hormiga 1994aHormiga 1994b: fig. 1A, B) but can be distinguished by the short and distally narrow cymbial denticulate process (Fig. 12B, vs. long and distally wide in P. binchuanensis; vs. distally wide in P. crispa); distinguished from P. binchuanensis by the nearly L-shaped pimoid cymbial sclerite (Fig. 12B, vs. nearly U-shaped); distinguished from P. crispa by a palpal tibia that is ca. 1/2 of the cymbial length ( Fig. 12A-C, vs. tibia almost the same length as cymbium). The female of P. samyai resembles P. crispa Hormiga, 1994(see Hormiga 1994a and P. indiscreta Hormiga, 1994(see Hormiga 1994a but can be distinguished by the distance between the pair of  spermathecae which is ca. 1/2 the width of a spermatheca (Fig. 13C, vs. separated by ca. 1/4 the width of a spermatheca in P. crispa and P. indiscreta) and by the distally wide dorsal plate (Fig. 13C, vs. distally narrow in P. crispa and P. indiscreta).

Discussion
As a relict group, pimoids are ideal organisms for biogeographic study (Wang et al. 2008). Wang et al. (2008) estimated the divergence time of the North American and Asian species of Pimoa was approximately 110 Ma, and suggested that the discontinuous distribution was probably a consequence of the break-up of Laurasia. Mammola et al. (2016) inferred that European pimoids probably originated in the alpine region as a result of range contractions following dramatic climatic changes in the Alps after the mid Miocene. Based on our spider collections in the last years, we have found that many Pimoa species have colonized in the southern region of the Tibetan Plateau. This study describes eight new species, yielding a total of 17 Pimoa species from China. However, this is only the tip of the iceberg of Chinese Pimoa species, and more new species will be reported with further collections. Phylogeographic analysis of Pimoidae from China will be conducted when the majority of Pimoa species appear to be recorded.