Nine new species of the spider genus Stedocys (Araneae, Scytodidae) from China and Thailand

Nine new species of the genus Stedocys Ono, 1995 are described: Stedocys gaolingensis Wu & Li sp. n. (♂♀, Guangxi), S. huangniuensis Wu & Li sp. n. (♀, Guangxi), S. ludiyanensis Wu & Li sp. n. (♂♀, Guangxi), S. matuoensis Wu & Li sp. n. (♀, Guangxi), S. pulianensis Wu & Li sp. n. (♂, Guangxi), S. shilinensis Wu & Li sp. n. (♂♀, Hainan), S. xianrenensis Wu & Li sp. n. (♂♀, Guangxi), S. xiangzhouensis Wu & Li sp. n. (♂♀, Guangxi) from China, and S. zhaoi Wu & Li sp. nov. (♂♀, Kanchanaburi) from Thailand. Diagnoses of nine new species are provided. DNA barcodes for six new species are documented for future use and as proof of molecular differences between these species.


INTRODUCTION
The genus Stedocys was established by Ono (1995) based on male of S. uenorum Ono, 1995 collected from a cave in Thailand. Thus far, this genus comprises only three species: S. uenorum from Thailand, S. leopoldi (Giltay, 1935) from Malaysia and Thailand, and S. pagodas Labarque et al., 2009from China (World Spider Catalog, 2017. According to Ono (1995), the genus Stedocys is diagnosed by a short tarsus and relatively long bulb with an aciculate embolus. Diagnosis of the genus Stedocys may change based on molecular phylogenetic study if fresh material of S. uenorum available. However, it is not possible to recollect S. uenorum until now because no detailed information on the type locality.
In this paper, we describe nine new species of the genus collected in caves from China and Thailand. Morphological descriptions and photos are given for all new species.

MATERIAL AND METHODS
Specimens were examined and measured with a LEICA M205 C stereomicroscope. Images were captured with an Olympus C7070 wide zoom digital camera (7.1 megapixels) mounted on an Olympus SZX12 dissecting microscope, and they were montaged using Helicon Focus 6.6.1 image stacking software (Khmelik et al., 2006). Male and female genitalia were examined and photographed after dissection. Female copulatory organs were excised using sharpened needles and then transferred to lactic acid for examination under the microscope, after the fatty tissue dissolved, the vulvae were immersed in Hoyer's solution for imaging. The left male palp is shown unless otherwise indicated. All specimens are preserved in 75% ethanol. All measurements are taken in millimeters. Leg measurements are shown as: total length (femur, patella, tibia, metatarsus, tarsus). Leg podomeres were measured on their dorsal side. The distribution map was generated with ArcView GIS 3.2. References to figures in the cited papers are listed in lowercase (figure or figures); figures from this paper are noted with an initial capital (Figure or Figures). 1 Chelicerae were photographed with an FEI Quanta 450 environmental scanning electron microscope (SEM). Prior to examination, they were cleaned with an ultrasonicator and critical point dried with a Leica EM CPD300 automated criticalpoint dryer. Before critical point drying, these specimens were gradually dehydrated in increasing concentrations of ethanol for 24-48 hs. Dried specimens were then mounted sputter coated for 120s using a Leica EM SCD050 super cool sputter coater.
All specimens have been deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China. Specimens were stored in 95% ethanol at -20 °C. Total genomic DNA was extracted from legs of a single specimen. For six species we were able to obtain the DNA barcodes. The samples for S. gaolingensis Wu & Li sp. nov., S. huangniuensis Wu & Li sp. nov., S. pulianensis Wu & Li sp. nov., were not extracted successfully. A partial fragment of the mitochondrial gene cytochrome oxidase subunit I (COI) was amplified and sequenced following the protocol in Miller et al. (2010). Primers used in this study are: LCO1490 (5'-CWACAAAYCATARRGATA TTGG-3') and HCO-N-2198 (5'-TAAACTTCAGGGTGACCAA AAAATCA-3') (Folmer et al., 1994). Voucher information and GenBank accession Nos. for all samples are listed in Table 1.  Figure 17A-B).
Description. Total length (males and females) 10.26-23.05. Prosoma longer than wide, posteriorly domed, thoracic furrow present in some species. Chelicerae sturdy and long compared to fangs, with a triangular cheliceral medial lamina separated from the paturon's margin by a deep depression, with setae distribted on the cheliceral lobe, and stridulatory ridges in all females (Figures 18-21). Leg formula I-II-IV-III. All tarsi with well-developed onychia, and claw I and II with a bipectinate proclaw (see Labarque et al., 2009: 7, figures 21-24). Female palp with a pair of apical prolateral blunt macrosetae (see Labarque et al., 2009: 7, figures 27, 30). Colulus well defined, with developed posterior projection (see Labarque et al., 2009: 7, figures 31, 44, 46), if a feature isn't mentioned in a description, it is the same as that for the genus.
Male palp: Cymbium short, with short or no apical extension; embolus aciculate or coiled distally, without stylus in the apex of the bulb.
Vulva: Atypical for the family, with a single sclerotized plate ( Figures 5B, 15B), and slightly sclerotized post-or preepigastric foveae, with one or two pairs of spermathecae, arising from the epigastric furrow.
Natural history. Specimens were found in humid karst caves hanging on webs in the aphotic zone, far from the entrance of the cave, or at the low light zone of the cave.
Distribution. Southeast Asia (South China, Malaysia, Thailand). Etymology. The specific name refers to the type locality; adjective.

Stedocys gaolingensis
Diagnosis. The male can be easily distinguished from the other species by having the cymbium almost 2 times longer than the tegular part of the bulb ( Figure 1A-B), by the embolus being subequal to the palpal tarsus in length, and the embolus slightly bent ventrally; females are easily distinguished from other species by the large, round spermathecae ( Figure 2B).

Distribution.
Known only from type locality in Guangxi, China ( Figure 22). Natural History. The species was found in the aphotic zone, far from the entrance of the long, humid cave. Etymology. The specific name refers to the type locality; adjective.

Stedocys huangniuensis
Diagnosis. The female resembles that of S. gaolingensis sp. nov. (Figures 1-2) in having a pair of receptacles in the uterus externus, but can be easily distinguished from other species by the non-oval spermathecae and the relatively short distance between spermathecae ( Figure 3B).  Figure  3E), highest at the center, ocular area covered with few hairs around eyes, thoracic furrow absent ( Figure 3C). Eye diameters: PME 0.34; ALE 0.29; PLE 0.28. Chelicerae with 7 stridulatory ridges ( Figure 18C), fangs, endites, labium sternum and colulus follow generic pattern. ( Figure 3D). Habitus as in Figure 3C-E. Legs yellowish, without rings or spines. Opisthosoma brownishyellow dorsally, anterior half with 4 irregular spots and 5 pairs of chevron-like marks on posterior half. Colulus trapeziform. Vulva ( Figure 3B) with a pair of oval spermathecae, and the interdistance between spermathecae is 0.33.

Male: Unknown
Distribution. Known only from type locality in Guangxi, China ( Figure 22). Natural History. The female was found in the aphotic zone, deep inside the long, humid cave, hanging on its web with many immature spiders. Etymology. The specific name refers to the type locality; adjective.

Stedocys ludiyanensis Wu & Li sp. nov.
Diagnosis. The male can be easily distinguished from all known congeners in Stedocys by having the tarsus 2 times longer than the basal portion of the bulb, and by the long, slender and straight embolus that is 1.5 times longer than the tarsus ( Figure 4A      radiating stripes and reddish bands marginally, highest at the middle posteriorly, with an arcuate appearance from the dome to the clypeus in lateral view, covered by dense serrate hairs posteriorly, no thoracic furrow ( Figure 6A). Six eyes follow generic pattern. Eye diameters: PME 0.36; ALE 0.35; PLE 0.35. Chelicerae with seven stridulatory ridges mesally ( Figure 21C), fangs, endites, labium sternum and colulus follow generic pattern. Habitus as in Figure 6A. Legs yellowish, without spines or annulated marks, claws follow generic pattern. Opisthosoma whitish dorsally, the first half with two pairs of irregular marks extending laterally and three pairs of chevron-like marks on the posterior half. Spinnerets short, follow generic pattern; colulus oval, can be easily observed. Palps as in Figure 4A-F; palp blunt apically, the fusion of subtegulum and tegulum shorter than tarsus; the apex of tarsus covered with a dense cluster of hair, the apex of the embolus gradually curved, bulb implanted prolaterally in tarsus ( Figure 4B).
Distribution. Known only from type locality in Guangxi, China ( Figure 22). Natural History. The male was found in the aphotic zone, far from the entrance of the long, humid cave, hanging on its web. The females were found both closer to and far from the entrance of the long, humid cave.   1.33, 0.52, 1.05, -, 1.35). Carapace chestnut brown, with deep brown radiating stripes and one pair of oval marks ( Figure 7C), highest at the center, with few hairs around eyes, andlacking thoracic furrow ( Figure 7C). Six eyes follow the generic pattern. Eye diameters: PME 0.44; ALE 0.38; PLE 0.38. Chelicerae with a long series of 11 conspicuous, densely spaced stridulatory ridges ectally ( Figure 18D). Habitus as in Figure 7C-E. Legs brown, without spines and annulated marks.Opisthosoma black dorsally, with three pairs of transverse grey bands markings. The spermathecae interdistance is 1.25 ( Figure 7B).

Male: Unknown
Distribution. Known only from the type locality in Guangxi, China ( Figure 22). Natural History. The females were found in the low light and aphotic zone, both near to and far from the entrance of the long, humid cave, hanging on irregular webs with several immature spiders. There were many mature female species in the cave but no males were found after three hours of collecting by two people. Other material examined. 1♀, immature, same data as holotype.

Stedocys pulianensis Wu & Li sp. nov.
Etymology. The specific name refers to the type locality; adjective.
Diagnosis. The male species can be easily distinguished from all known congeners in Stedocys by the cylindrical tarsus, subequal to or longer than the basal portion of the bulb, and by the dense hair around the tarsus and tibia ( Figure 8A-B 3.11, 1.02, 3.05, -, 0.65). Carapace chestnut brown, with yellowish-brown vertical stripes and reddish bands marginally, highest at center, with a few hairs posteriorly, and no thoracic furrow ( Figure 9A). Six eyes follow the generic pattern. Eye diameters: PME 0.35; ALE 0.32; PLE 0.32. Chelicerae with a series of spaced inconspicuous stridulatory ridges ectally ( Figure 21A), fangs, endites, labium, sternum, and spinnerets follow the generic pattern. Habitus as in Figure 9A-C. Legs brown, without rings or spines. Opisthosoma brown dorsally, with two whitish-brown transverse bands. Colulus triangular. Palps as in Figure 8A-F; palp with a long embolus, apically aciculate.
Distribution. Known only from type locality in Guangxi, China ( Figure 22). Natural History. The male was found in the aphotic zone. Far from the entrance of the humid cave, hanging on its web. Paratypes: 4♀, same data as holotype.

Stedocys shilinensis Wu & Li sp. nov.
Etymology. The specific name refers to the type locality; adjective.
Diagnosis. The male can be easily distinguished from all known congeners by having an apophysis on the bulb of male palp ( Figure 10A-B) and the female genitalia contains a simple median unpaired sclerotized plate ( Figure 11B).

Distribution.
Known only from type locality in Hainan, China ( Figure 22). Natural History. The species was found in the aphotic zone, far from the entrance of the long, humid cave, hanging on its web. Etymology. The specific name refers to the type locality; adjective.

Stedocys xianrenensis Wu & Li sp. nov.
Diagnosis. The male can be easily distinguished from all known congeners by the relatively short tarsus that has a small extension, by the tarsus being subequal or smaller than the oval basal portion of the bulb, and by the triangular tarsus in retrolateral view (Figure12A-B). The female can be easily distinguished from other species by the very large pair of round spermathecae ( Figure 13B).

Distribution.
Known only from type locality in Guangxi, China ( Figure 22). Natural History. The species was found in the aphotic zone, far from the entrance of the long, humid cave, hanging on its web. Etymology. The specific name refers to the type locality; adjective.

Stedocys xiangzhouensis
Diagnosis. The male can be easily distinguished from all known congeners by having the palpal tarsus a little longer than the basal portion of the bulb, by the long, stout and straight embolus that is 1.5 times as long as the basal portion of the bulb ( Figure 14A-B). The female resembles S. ludiyanensis Wu & Li sp. nov. (Figures 4-6) in having a pair spermathecae beside the uterus externus, by the shape, enclosed by the curved anterior plate and posterior plate, by the postepigastric fovea with postgastral sulci, and by the unpaired posterior sclerotization beneath the posterior sclerotized plate. Additionally, it can be easily distinguished by the large oval spermathecae beside the uterus externus and the trapezoidal unpaired posterior sclerotized plate ( Figure 15B).  Leg I: 53.95 (19.75,1.15,19.95,11.35,1.75),leg II: 30.08 (8.95,1.18,8.65,9.65,1.65),leg III: 18.62 (5.69,1.15,5.15,5.58,1.05),leg IV: 26.45 (7.58,1.32,7.85,7.95,1.75),palp: 6.10 (2.15,0.77,2.44,0.74). Carapace brown, with black brown radiating stripes and longitudinal bands marginally, highest at the center, covered by dense hairs posteriorly, and with no thoracic furrow ( Figure 15C). Six eyes follow the generic pattern. Eye diameters: PME 0.26; ALE 0.26; PLE 0.26. Chelicerae without conspicuous obvious spaced stridulatory ridges ( Figure  20B). Fangs, endites, labium, sternum, and spinnerets follow the generic pattern. Habitus as in Figure 15C. Legs yellowish, relatively long and slender, with spines on leg I and leg II, and claws follow the generic pattern. Opisthosoma slightly yellowish dorsally, without regular markings. Colulus trapeziform. Palps as in Figure 14A-F; palp with a long embolus, apically aciculate; tarsus smaller than or subequal to the basal portion of the bulb; apex of tarsus covered with dense cluster of hairs.

Distribution.
Known only from type locality in Guangxi, China ( Figure 22). Natural History. The species was found in the aphotic zone, far from the entrance of the long, humid cave, hanging on its web. Etymology. The specific name is a patronym in honor of the collector Huifeng Zhao; noun (name) in genitive case.

Stedocys zhaoi
Diagnosis. The species can be easily distinguished from all known congeners by the coiled embolus distally ( Figure 16A-F), the conspicuous arcuate sclerotized structure of the female external genitalia (Figure 17A), and by the two pairs of round spermathecae on long, curved stalks ( Figure 17B).
Distribution. Known only from type locality in Kanchanaburi, Thailand ( Figure 22). Natural History. The species was found in the aphotic zone of the cave.