Taxonomic study on fourteen symphytognathid species from Asia (Araneae, Symphytognathidae)

Abstract Fourteen symphytognathid species belonging to three genera are examined, including the descriptions of eight new species and two new genera from China, Vietnam, Thailand and Myanmar: Patu Marples, 1951: P.catba S. Li & Lin, sp. nov. (♂, Vietnam), P.dakou S. Li & Lin, sp. nov. (♂♀, China), P.damtao S. Li & Lin, sp. nov. (♂, Vietnam), P.jiangzhou S. Li & Lin, sp. nov. (♀, China), P.jidanweishi Miller, Griswold & Yin, 2009 (♂♀, China), P.nagarat S. Li & Lin, sp. nov. (♂♀, Thailand), P.nigeri Lin & S. Li, 2009 (♀, China), P.putao S. Li & Lin, sp. nov. (♀, Myanmar), P.qiqi Miller, Griswold & Yin, 2009 (♀, China) and P.xiaoxiao Miller, Griswold & Yin, 2009 (♂♀, China); Kirinua S. Li & Lin, gen. nov.: K.maguai S. Li & Lin, sp. nov. (♂♀, China) and K.yangshuo S. Li & Lin, sp. nov. (♂♀, China); Swilda S. Li & Lin, gen. nov.: S.longtou (Miller, Griswold & Yin, 2009), comb. nov. (♂♀, China) is transferred from Crassignatha Wunderlich, 1995 and S.spinathoraxi (Lin & S. Li, 2009), comb. nov. (♂♀, China) is transferred from Patu. Diagnoses, descriptions and illustrations are provided for new taxa, as well as a distribution map. The males of P.xiaoxiao and S.longtou are described for the first time. Type specimens of P.jidanweishi, P.nigeri, P.qiqi, P.xiaoxiao, S.longtou and S.spinathoraxi are re-examined and photographed. All Asian Patu species are revised and two species, P.kishidai Shinkai, 2009 and P.bispina Lin, Pham & S. Li, 2009, are transferred to Crassignatha and proposed as new combinations: Crassignathakishidaicomb. nov. and C.bispinacomb. nov. In addition, DNA barcodes and genetic distances of ten species treated in this paper were obtained to confirm identification.


Introduction
Symphytognathidae Hickman, 1931 is a small spider family mainly distributed in tropical and subtropical regions of the Oriental and Neotropical realms. Ninety symphytognathid species in eight genera are known, of which 45 species and six genera occur in Asia (WSC 2021).
Before the current study, fourteen species from China, Colombia, Fiji, Japan, New Guinea, Samoa, Seychelles and Vietnam were assigned to Patu Marples, 1951. Miller et al. (2009 mentioned that Patu is a particularly problematic genus because of insufficient study of the copulatory organs, the scarcity of material in collections and the minute size of these animals. A complete revision of this genus is still lacking and the taxonomic placement of some doubtful species needs to be clarified.
The aim of this paper is to provide data on Asian Patu and related genera, including descriptions of new species and genera, based on recent collections from China, Vietnam, Thailand and Myanmar.

Materials and methods
More than 1200 adult symphytognathid specimens were examined in a 95% ethanol solution under a Leica M205 C stereomicroscope. The digital photos were montaged using Helicon Focus 3.10 (Khmelik et al. 2006) image stacking software. Male palps and epigynes were examined and photographed after dissection. The left palp was photographed and described (if missing, the right was used). Epigynes were treated with lactic acid before being embedded in Hoyer's Gum and placed on an ultra-thin slide to take photos of both sides of the vulva. All measurements are in millimetres. Leg measurements are given as follows: total length (femur, patella, tibia, metatarsus and tarsus).
Tissue samples were taken from the prosoma of 17 individuals of Patu, Kirinua S. Li & Lin, gen. nov. and Swilda S. Li & Lin, gen. nov., including five new and five known species (the abdomens and male palps were kept as vouchers). All of the molecular data were obtained from specimens collected at the type localities, although not from the type specimens themselves. A partial fragment (636 bp) of the mitochondrial gene cytochrome c oxidase subunit I (COI) was amplified and sequenced to calculate the genetic distances between morphologically-similar species to confirm identifications and for sex pairing.
The primers used were: LCO1490 (5'-GGTCAACAAATCATCATAAAGA-TATTGG-3') and HCO2198 (5'-TAAACTTCAGGGTGACCAAAAAA TCA-3'). Raw sequences were edited and assembled using BioEdit v.7.2.5 (Hall 1999) and the uncorrected pairwise distances between species were calculated using MEGA7.0.14 (Kumar et al. 2016). Results of the genetic distance analysis are shown in Appendix Table A1.  Morphological abbreviations used in the figures are given in Table 1. New sequences, generated for this study, are available from GenBank and the accession numbers are reported in Table 2. References to figures in the cited papers are listed in lowercase (fig. or figs) and figures in this paper are noted with an initial capital (Fig. or Figs). With the exception of the types of previously-described species kept in HNU and IZCAS, all molecular vouchers are deposited in NHMSU in Chengdu, China and examined morphological material is deposited in NHMSU and IZCAS.
Remarks. Of the male Patu species described here, the embolus is either embedded within the tegulum or not, the conductor is present or absent and the tegular process is present or absent. The similarities of the palps are the nearly ovate bulb and the cymbium lacking any teeth, processes or apophyses. In the females, the epigyne and vulva distinctly differ in the type, shape and size of posterior process of the epigyne (scape or parmula) and in the texture, length and course of the copulatory ducts. The similarities of the vulvae are the ovate or short, club-shaped spermathecae. Etymology. The specific epithet derives from the type locality; noun in apposition. Diagnosis. This new species differs from other Patu species with the exception of P. damtao sp. nov. by having a long, sclerotised conductor dorsally on the bulb (Figs 1D and 4D). It can be distinguished from P. damtao sp. nov. by the blunt conductor swollen basally, the shorter embolus forming no more than one loop and the presence of a median apophysis ( Fig. 1D and E) vs. a sharp conductor constricted basally, a longer embolus forming more than one loop and the absence of a median apophysis ( Fig. 4D and E).
Somatic characters (Fig. 2D-F). Colouration: prosoma same as in male, opisthosoma light, ventrally darker than dorsally, post-gaster region and area around spinnerets black. Prosoma: carapace round. Cephalic region lower than in male. PER slightly procurved. Mouthparts and sternum as in male, except longer labium. Legs: as in male. Opisthosoma: dorsally rounded, laterally ovate, covered with sparse, long, black setae. Spinnerets dark grey. Epigyne ( Fig. 3C-F): internal structures faintly visible via cuticle. Parmula knobshaped, protruded, distally sclerotised. Copulatory opening large, oval. Copulatory duct arising from the ventral base of parmula, its proximal part forming a pair of sclerotised, broad, horn-like structures at both sides of spermathecae. Spermathecae shorter than width of copulatory opening, claviform, nearly touching. Fertilisation ducts start at the anterolateral margin of spermathecae and curve downwards to centre of vulva.
Distribution. China (Yunnan) (Fig. 23). Etymology. The specific epithet derives from the name of the type locality; noun in apposition.
Diagnosis. Patu damtao sp. nov. can be distinguished from other congeners, with the exception of P. catba sp. nov., by having a conductor and lacking a tegular process (Fig. 4D). It is similar to P. catba sp. nov. in the shape of the male palp, but it differs by lacking a median apophysis, the embolus has more coils and is 4× the length of the conductor vs. having a median apophysis and an embolus with fewer coils that is ca. 2× the length of the conductor (Figs 4D and E vs. 1D and E).
Female. Unknown. Distribution. Vietnam (Fig. 23). Etymology. The specific epithet derives from the name of the type locality; noun in apposition.
Male. Unknown. Distribution. China (Guangxi) (Fig. 23).    Diagnosis. This species differs from other congeners, except for P. nagarat sp. nov., by lacking a median apophysis and a conductor and having a tegular process and a long scape (Fig. 7A, B and F). It is similar to P. nagarat in the shape of the bulb and the configuration of the vulva, but it can be distinguished by the lack of a median apophysis, a tegular process that is shaped like the head of a sparrow (Fig. 7B) and by the rugose, finger-like scape and the more widely separated spermathecae ( Fig. 7A-F) vs. having a median apophysis and a pyramidal tegular process, a broader, triangular parmula and spermathecae are closer ( Fig. 9A-F Etymology. The specific epithet derives from the type locality; noun in apposition. Diagnosis. The male of P. nagarat sp. nov. can be distinguished from that of other congeners by having a bifurcate, sclerotised median apophysis and a pyramidal tegular process and lacking a conductor ( Fig. 9A and B) vs. lacking a median apophysis (or if present, it is not furcate) and/or having a conductor (Figs 1D, 4D, 7A and 14A). The female is similar to that of P. jidanweishi in the configuration of the vulva, but it differs by having a triangular parmula and the spermathecae are closer together, rather than a finger-like scape and more widely separated spermathecae (cf. Figs 9C-F and 7C-F).
Somatic characters (Fig. 8D-F). Colouration: same as in male. Prosoma: carapace ovate dorsally. Ocular area slightly more anterior than in male. Cephalic part slightly lower than in male. Legs: colour of tibia, metatarsi and tarsi darker than in male. Opisthosoma: same as in male.
Epigyne ( Fig. 9C-F): weakly sclerotised, with a few setae medially, internal structures of vulva faintly visible via the cuticle. Parmula large, triangular, protruded ventrally. Copulatory openings located on the bilateral corners of parmula base. Spermathecae oval, distally tilted slightly downwards. Copulatory ducts mostly membranous and rugose. Proximal portion of copulatory ducts weakly sclerotised, originating at ventrolateral corners of parmula base, distal portion connected to the posterolateral margin of spermathecae. Fertilisation ducts short, starting at the anterolateral margin of spermathecae.
Distribution. Thailand (Fig. 23). Diagnosis. The male of P. nigeri differs from that of other congeners, except P. dakou sp. nov., P. silho, and P. xiaoxiao, by lacking an exposed embolus ( fig. 4A and B in Lin and Li 2009), a median apophysis and a tegular process. The male differs from P. dakou sp. nov. by the smaller tegulum (~ ¾ size of that of P. dakou sp. nov.) (Fig. 3A vs. fig. 4A in Lin and Li 2009), from P. silho by the elongate oval palpal bulb (short oval in P. silho)   fig. 5A and B in Saaristo, 1996) and differs from P. xiaoxiao by the absence of a tegular process (finger-like tegular process in P. xiaoxiao) ( fig. 4A and B in Lin and Li 2009 vs. Fig. 14A and B). The female of P. nigeri is similar to that of P. putao sp. nov. by the shape of the epigyne (Figs 10D, E, 11D and E) and to P. qiqi in the configuration of the vulva (Figs 10G and 12G), but it can be easily distinguished from P. putao sp. nov. by the short and straight copulatory ducts, rather than long and twisted as in P. putao sp. nov. (cf. Figs 10F-G and 11F-G) and from P. qiqi by the tongue-shaped parmula that does not obscure the copulatory openings, rather than an indistinct scape that hides the copulatory openings (cf. Figs 10G and 12G).

Diagnosis.
This new species is similar to P. jiangzhou sp. nov. and P. nigeri in the shape of the epigyne, the tongue-shaped parmula and the exposed copulatory openings, but it differs from P. jiangzhou sp. nov. by the rounded copulatory openings, the longer copulatory ducts and the larger, reniform spermathecae, rather than trumpetshaped copulatory openings, shorter copulatory ducts and smaller, oval spermathecae (cf. Figs 11D and F-G vs. 5D and F-G) and from P. nigeri by the longer, twisted copulatory ducts that wrap around the spermathecae, rather than the shorter, straight copulatory ducts that do not wrap around the spermathecae (cf. Figs 11G and 10G).
Male. Unknown. Distribution. Myanmar (Fig. 23).  fig. 5A and B in Saaristo 1996) and it differs from P. xiaoxiao by lacking a tegular process (cf. fig. 73A in Miller et al. 2009 and Fig. 14A). The female is most similar to that of P. nigeri in the shape of the epigyne and the configuration of the vulva, but it can be easily distinguished by the indistinct scape and the hidden copulatory openings vs. a tongue-shaped parmula and exposed copulatory openings (cf. Figs 12F-G vs. 10F-G).

Patu qiqi
Description. See  Diagnosis. The male of P. xiaoxiao can be distinguished from other congeners, with the exception of P. woodwardi, by the stout bulb lacking a conductor or me-  dian apophysis and having a finger-like tegular process ( Fig. 14A and B). It differs from P. woodwardi by having the entire embolus completely embedded in the bulb (cf. Fig. 14A and B and fig. 120 in Forster 1959). Females of P. xiaoxiao differs from those of other congeners by having a wide, triangular parmula, dumb-bell-shaped spermathecae separated by ~ 1.5× their width and arranged longitudinally in parallel, the copulatory ducts coiling into a loop and connecting to the postero-lateral corner of the spermathecae, the fertilisation ducts begin latero-medially on the spermathecae (Fig.  14C-E).
Somatic characters (Fig. 13A-C). Colouration: carapace light brown, thoracic centre and margin with darker patches. Mouthparts nut brown, endites and labium black. Sternum black, with a few light, small dots. Leg colour light yellow gradually grading to very dark brown, tibia darkest brown. Abdomen dorsally light grey, laterally dark greyish, ventrally and posteriorly charcoal black. Prosoma: carapace as long as wide, nearly round. Cephalic part vertical anteriorly and sloped posteriorly. Eyes, subequal in size. PER slightly recurved, ALE protruded. Chelicerae anterior surface flat. Labium semicircular, wider than long. Sternum smooth, slightly plump. Legs: each patella with 1 disto-dorsal seta, 1 proximal and 1 disto-dorsal seta on each tibia. Tibia II with 2 ventral clasping spines. Opisthosoma: dorsally globose, laterally ovoid, clothed with black, long setae, cuticle rough with dots of varying shades and sizes. Spinnerets dark brown. Palp ( Fig. 14A and B): size ~¼ of carapace. Femur swollen, wider than patella, patella as long as ~ ½ length of tibia. Tibia flat and lamellar. Tegulum smooth, with finger-like apical process. Embolus long, starting at retrolatero-medial part of tegulum, coiled into 2 loops inside bulb. Tip of embolus hidden within tegulum, not extended from top of bulb.
Somatic characters (Fig. 13D-F). Colouration: as in male, except lighter mouthparts and sternum. Prosoma: carapace longer than wide, pear-shaped. Eye arrangement as in male. PER straight. Cephalic part lower than in male. Legs: spination as in male, except for lack of clasping spines on tibia II. Opisthosoma: subovoid in dorsal view, cuticle. Spinnerets dark grey.
Epigyne (Fig. 14C-E): faintly sclerotised, internal structures nearly invisible via the cuticle. Parmula triangular, length equal to ca. ½ width, slightly protruded. Spermathecae nearly dumb-bell-shaped, longitudinally parallel, separated by ~ 1.5× their width. Copulatory openings large. Copulatory ducts translucent, their width equal to ca. 2.5× width of fertilisation ducts and folded at middle, distal part connected with postero-lateral part of spermathecae. Fertilisation duct shorter than a spermatheca length, narrow, originates from the lateral central position of spermathecae.
Relationships. Kirinua gen. nov. is characterised by their tiny size, chelicerae fused at mid-line, AMEs and book lungs absent, female lacking palps and tarsi much longer than metatarsi. This new genus is similar to Patu by having 2 clasping spines on male tibia II, lacking an abdominal scutum latero-posteriorly in the male and the carapace of both sexes lacks modified pits or sculpturing (Figs 15A-H and 17A-H). The new genus differs from Patu by the highly modified structures of the cymbium (e.g. primary apophysis, process) and the epigyne has nearly spherical spermathecae and a broad atrium (Figs 16A, G, 18A and F). Etymology. The specific epithet derives from the name of the type locality; noun in apposition.
Female ( Somatic characters (Fig.. 15D-F). Colouration: same as in male. Prosoma: carapace nearly pear-shaped in dorsal view. Cephalic part elevated, lower than in male. PER slightly procurved. Legs: spination of each leg as in male. Opisthosoma: as in male, except for wrinkled abdominal cuticle that may be caused by ethanol dehydration. Epigyne (Fig.. 16D-G) internal structures faintly visible via the translucent epigynal cuticle. Scape barely visible. Vulva relatively complex. Spermathecae subglobose, close to posterior margin, separated by about 2 diameters. Fertilisation duct thinner than copulatory duct, located dorso-posteriorly on copulatory duct, originates from posteromedial margin of spermatheca, curved outwards at sides of atrium, then extended downwards (Fig. 16G).
Somatic characters (Fig. 17D-F). Colouration: same as in male. Prosoma: carapace longer than wide, as long as high. Cephalic part lower than in male, flat dorsally. PER slightly recurved. Legs: spination of each leg as in male. Opisthosoma: laterally oviform. Spinnerets Located ventrally.
Epigyne : plate wider than long, strongly sclerotised. Scape wider than long, slightly protruded. Spermathecae globose, separated by more than 3.5 diameters. Copulatory ducts long, their proximal parts enlarged, forming a broad, inverted, subtriangular atrium, with knob-shaped lateral humps; middle part coiled more than 5 times; distal part connected longitudinally to spermatheca. Fertilisation duct slightly bent, runs along lateral wall of atrium, originating above coiled part of copulatory duct.
Distribution. China (Guangxi) (Fig. 23). Etymology. The generic name Swilda is derived from the Swild Studio (in Chinese: Xi Nan Shan Di Gong Zuo Shi). It is named after the organisation in honour of its dedication to promoting public advocacy for wildlife conservation and nature education in southwest China. The gender is masculine.

Genus
Diagnosis. Swilda gen. nov. is easily distinguished from other symphytognathids, except Crassignatha, by having an anteromedially-split dorsal scutum in the male and a highly ornamented spinous and pitted carapace in both sexes (Figs 19A,D,21A and D). It resembles Crassignatha in carapace texture and the spherical spermathecae. The male differs from those of Crassignatha by having a conductor and lacking a cymbial tooth (Figs 20A and 22A) vs. lacking a conductor, but having a cymbial tooth (figs 2A, 8A and 10A in Li et al. 2020); the female differs in lacking a scape and by the separated copulatory openings (Figs 20F and 22E) vs. having a protruded scape and the adnate copulatory openings located at the apex of the scape in Crassignatha (figs 2G, 4G and 8G in Li et al. 2020).
Relationships. Swilda gen. nov. is characterised by its tiny size, fused chelicerae at mid-line, AMEs and book lungs absent, female lacking palps and tarsi much longer than metatarsi. Here, the male of C. longtou is described for the first time and specimens of P. spinathoraxi are re-examined. We found the morphological features of these two species to be very similar to those of Crassignatha (see Li et al. 2020: 65), sharing the following combination of characters: a clasping spine on tibia II and an abdominal scutum latero-posteriorly in the male and a decorated carapace and sclerotised epigastric scutum in both sexes . The differences between these two species and Crassignatha are: a pitted and spinous carapace, a sclerotised annular plate that encircles the spinnerets (cf. Figs 19A-F and 21A-F vs. figs 1A-F and 7A-F in Li et al. 2020), only 1 male clasping spine (cf. Figs 19B and 21B vs. figs 1B and 12C in Li et al. 2020: only 1 spine in a few species), male palps lack a cymbial tooth, but have a conductor (cf. Figs 20A and 22A vs. figs 2A and 8A in Li et al. 2020) and the epigyne lacks a protruded scape (cf. Figs 20E-F and 22E-E vs. figs 2E and 6E in Li et al. 2020).
The genetic distance we estimated, based on COI, also indicated differences between these two species and members of other genera (see Appendix Table A1). Phylogenetic analysis of molecular data indicates that P. spinathoraxi and C. longtou are clearly congeneric. Additionally, the combined genetic evidence from five genes supports the monophyly of Swilda gen. nov. and the sister group relationship of the two genera (unpubl. data). Therefore, Swilda gen. nov. is proposed as a new genus in which to place S. longtou (Miller et al, 2009) comb. nov., transferred from Crassignatha and S. spinathoraxi comb. nov., transferred from Patu. We designate Swilda longtou as the type species for this new genus.
Distribution. China (Yunnan) (Fig. 23). Diagnosis. The male of S. longtou can be distinguished from that of S. spinathoraxi by the larger proximal cymbial process (CP1), the human-ear-shaped median apophysis and the wider and longer conductor (Fig. 20A) vs. needle-like proximal cymbial process (CP1), mastoid median apophysis and narrower and shorter conductor (Fig. 21A). The female differs by the separated copulatory openings, spermathecae separated by less than one diameter in S. longtou vs. adjacent copulatory openings, spermathecae separated by more than one diameter in S. spinathoraxi (cf. Figs 20E and F and 22D and E).
Embolus long, jutting out from prolateral margin of tegulum, curved upwards, extended beneath distal part of cymbium.
Somatic characters (Fig. 21D-F). Colouration: prosoma and legs as in male. Abdomen pale dorsally and light grey ventrally. Carapace modified as in male. Cephalic part lower than in male. Legs: the spination same as in male, except tibia II lacking clasping spine. Opisthosoma: globose, with sparse, long setae, without posterolateral scutum. Other modifications same as in male.

Discussion
The taxonomy of genus Patu is revised in the current study and the taxonomic positions of some puzzling Asian Patu species are resolved. However, the species here are only the "tip of the iceberg" of Asian Patu species (Yao et al. 2021) and further studies are necessary to revise the worldwide Patu spiders. Table A1. Uncorrected genetic pairwise distances (lower triangle) and standard errors (upper triangle) of a partial fragment of COI from ten species discussed in this text.