Psechrus kunmingensis: description of male and supplementary description of female, with discussion on intraspecific variation (Araneae, Psechridae, Psechrus)

Abstract Psechrus kunmingensis Yin, Wang & Zhang, 1985 was first described from the female only. The first illustration of the male appeared without any text description and lacked other critical information. For this study, we collected fresh specimens of this species from diverse localities around Yunnan Province, China. Here, the male is described in detail for the first time and a supplementary description of the female is given. Based on the largest collection of Psechrus kunmingensis specimens ever assembled, we found a remarkably high level of morphological variation in this species.


Introduction
Psechridae Simon, 1890 is a small spider family with 2 genera, 46 species (Bayer 2012). Among them, 14 species belonging to both genera are reported from China (Li and Wang 2012). The distribution of psechrids runs from southern China and South East Asia to Queensland, Australia (Platnick 2012). Up to now, there were three revisions on this family: Levi (1982) made a revision of all psechrids known at that time, Wang and Yin (2001) focused on psechrids in China, and recently Bayer (2011Bayer ( , 2012 respectively revised all species of Fecenia and Psechrus. In the genus Psechrus, several species are known from only one sex. Psechrus borneo Levi, 1982, P. kunmingensis Yin, Wang & Zhang, 1985, P. jinggangensis Yin, 2001, andP. kenting Yoshida, 2009, for example, are known only from females. Many species of Psechrus vary a lot and it is very important to differentiate intraspecific variation from characters of different species. Levi (1982) illustrated variation of several species, but Bayer (2012) pointed out that Levi considered clearly differing structures of copulatory organs as intraspecific variation.
Psechrus kunmingensis was described and illustrated for the first time by Yin et al. (1985) based on 4 female specimens collected from Kunming, Yunnan Province, China. Later, Song et al. (1999) illustrated both the male and the female, but provided neither descriptions nor exact specimen collection locality or place of deposition. They gave no justification for their conclusion that the male they illustrated was conspecific with P. kunmingensis. Wang and Yin (2001) redescribed and illustrated the female.
We examined specimens collected from the type locality of P. kunmingensis (Kunming, Yunnan Province, China) at the same time of year (April to July) and many specimens from places around Kunming. Based on examination of these specimens, we concluded that the male illustrated by Song et al. (1999) is indeed conspecific with the P. kunmingensis female. In the present paper, the male of P. kunmingensis is described in detail. Additionally, a supplementary description of females is provided. We illustrate and describe a high level of morphological intraspecific variation for the first time, which will be important for further research and proper identification of this species. Some photographs generated in the course of this study were shared with Steffen Bayer and appeared with our permission in the recent taxonomic revision of Psechrus (Bayer 2012). Based on this, Bayer was able to include a brief description of the male palp of P. kunmingensis in his monograph. In this paper, we are able to provide a more complete description of the male anatomy and coloration, measurement data, and a survey of intraspecific variation.

Methods
Specimens were preserved in 75% ethanol. Female copulatory organs were dissected and cleared in 90% lactic acid for a few minutes. Photographs were taken with Nikon digital Sight DS-Fi1 mounted on Nikon SMZ1000 Stereoscopic Zoom Microscope. Copulatory organs were illustrated using Adobe Illustrator CS5, with a Wacom Bamboo CTL-660 pen and tablet device. Illustrations were rendered in Adobe Photoshop CS5 Extended.
All measurements are in millimeters (mm), and taken with Nikon NIS-Elements Imaging Software Br (version 2.34). All scale bars are 0.5mm length. We measured two male specimens and 5 female specimens to obtain size range data. Specimens were selected to cover the widest possible size range. The "prosoma length" or "opisthosoma length" respectively refers to length of the main part of prosoma or opisthosoma , without spinnerets and petiolus. The whole "body length" is regarded as length from clypeus to the posterior tip of opisthosoma. Every individual was given a code, consisting of abbreviation of the locality and a sequence number. For instance, "KM18" represents a specific specimen collected from Kunming. Non-quantitative descriptions of somatic morphology are based on KM37 (female) and KM38 (male). Palpal and leg spination pattern is given as: prolateral, dorsal, retrolateral, ventral (the latter digit may be omitted in the case of the absence of ventral spines) (Jäger and Kunz 2010). The term "subadult" female refers to specimens that possess only pre-epigynes (Bayer 2011). All material is deposited at College of Agronomy and Bioscience, Dali University, Yunnan, China, except the following specimens, which are deposited at Senckenberg Museum, Frankfurt am Main, Germany (SMF): 1 male (KM04), one female (KM07) and one subadult female (KM25).
Carapace brown, with a gray band at central part and white hair along the margin (Fig. 4). Cervical groove and fovea with dark stripe (Fig. 4). Eight eyes arranged in two recurved rows, eye region with long white hairs (Fig. 6). Sternum light brown, with an inverted triangle dark mark and long hairs. Labium deep reddish brown; gnathocoxae brown. Chelicerae yellow at basal part, and reddish brown at terminal  Yin, Wang & Zhang, 1985. Intraspecific variation of male palp, retrolateral. Arrows indicate the triangular apophysis besides embolus (Scale bar 0.5mm). Yin, Wang & Zhang, 1985. Intraspecific variation of female copulatory organ (left row, epigyne, ventral; right row, vulva, dorsal). (Scale bar, 0.5mm). part, with 3 promarginal, 5 retromarginal teeth, and 3 denticles (Fig. 8). Legs yellow to reddish brown; Coxae and trochanteri of the first walking legs with short macrosetae in a distal row each (Fig. 9). Patellae of legs with a slit at retrolateral side (Fig.  5). Dorsal opisthosoma dark gray, with a pair of longitudinal black patches at lateral side, and pairs of white radiative patches. Ventral opisthosoma with a white band, from pedicel to cribellum.
Spination of palp and legs as shown in Table 1; Measurements of the palp and legs as shown in Table 2. KM38 first, KM03 in parentheses. Leg formula: 1423.
Coloration  as in male only generally darker; other characters as in male except as noted. Chelicerae with 3 promarginal, 5 retromarginal teeth, and 4 denticles (Fig. 16). Patellae of legs with a slit at retrolateral side (Fig. 15).
Female copulatory organ: the SO and SG are outside the epigynal field (the SO are anterior and lateral to the epigyne, while the SG are right anterior to the epigyne); the MS lobed at the posterior and lateral edges; there are many wrinkles at the epigyne, especially at the anterior part (Fig. 20); the shadow of the round spermathecae is evidently visible through the ventral view of epigyne (Fig. 10). Copulatory ducts coiled; the spermathecae is mostly covered by folds of LL and MS; the spermathecal heads arise anteriorly at spermathecae (Figs 11,21). The incision at posterior margin of MS, shape of lobes of MS, the length of CD and shape of SH vary a lot (Fig. 24); schematic course of internal duct system shown in Fig. 22.
Note. Illustrations given in previous publications about P. kunmingensis were wrong with the arising position of the spermathecal heads or the position of the spermathecae. Yin et al. (1985, 25, Fig. 5A-D) and Song and Chen (1999, 397 Fig. 232 C-D) were almost the same. They mis-illustrated the spermathecal heads arise posteriorly. The spermathecae are at lateral vulva not medial vulva as shown by Wang and Yin (2001, 334, Figs 9-10).
Spination of palp and legs as shown in Table 1; Measurements of the palp and legs as shown in Table 2. KM37 first, those of others given as ranges in parentheses. Leg formula: 1423.
Intraspecific variation. All 6 examined males were collected from the type locality. The distal fork of EA is relatively variable (Fig. 23): one male (KM18) with 2 short and tiny apophysis, some with relatively strong and blunt forks (KM01, KM04 and KM38), while others exhibit slender and sharp forks with the ventral one curved distally (KM02 and KM03).
All examined adult females vary in many aspects (Figs 10-11, 24a, 24b): 1) the number of SO varies from five (KM05, ZT01, HN01 and WN01) to seven (KM37 and KM36); 2) incision at posterior margin of MS is less distinct in some individuals (XW06, WN01, LX03 and KY02), but others are evident and symmetrical (KM37,  University, Chongqing) and Professor Feng Zhang (Hebei University, Baoding, Hebei) for the loan of specimens. Many thanks to Steffen Bayer (Senckenberg Research Institute and Natural History Museum, Frankfurt am Main, Germany), who kindly gave many useful comments on this manuscript, as well as specimens observation, photography and psechrid taxonomy. Also many thanks to Jeremy Miller (Naturalis Biodiversity Center, Leiden), for his valuable comments on this manuscript and improving the quality of English. We appreciate Peter Jäger and Xin Ping Wang and one anonymous referee for their helpful recommendations on this manuscript.