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A review of Crassignatha (Araneae, Symphytognathidae)

Abstract Crassignatha Wunderlich, 1995 is redefined to include species with six eyes in three diads, chelicerae fused only near the base, sculpturing on the carapace, one or two clasping spurs on tibia II, a bilateral scutum of the male abdomen, and globular spermathecae and adjacent copulatory openings in the female. A key and distribution map are provided for 24 Crassignatha species in this paper. Diagnoses and illustrated photographs are provided for 22 species from China, Malaysia, Thailand, and Vietnam. Thirteen species are described and documented as new to science: C. baihua Y. Lin & S. Li, sp. nov. (♂♀), C. bangbie Y. Lin & S. Li, sp. nov. (♀), C. changyan Y. Lin & S. Li, sp. nov. (♀), C. dongnai Y. Lin & S. Li, sp. nov. (♀), C. gucheng Y. Lin & S. Li, sp. nov. (♂♀), C. mengla Y. Lin & S. Li, sp. nov. (♂♀), C. nantou Y. Lin & S. Li, sp. nov. (♂♀), C. nasalis Y. Lin & S. Li, sp. nov. (♂♀), C. rostriformis Y. Lin & S. Li, sp. nov. (♂♀), C. shunani Y. Lin & S. Li, sp. nov. (♂♀), C. si Y. Lin & S. Li, sp. nov. (♂♀), C. thamphra Y. Lin & S. Li, sp. nov. (♀), and C. xichou Y. Lin & S. Li, sp. nov. (♀). Three new combinations are proposed: C. bicorniventris (Lin & Li, 2009), comb. nov., C. quadriventris (Lin & Li, 2009), comb. nov., and C. shiluensis (Lin & Li, 2009), comb. nov. are transferred from Patu Marples, 1951. DNA barcodes and genetic distances of seventeen species are obtained to confirm correct identification. Types of seven known Chinese Crassignatha species are re-examined, and the taxonomic placement of C. longtou Miller, Griswold & Yin, 2009 may be incorrect based on morphological and molecular data.


Introduction
Symphytognathidae Hickman, 1931 is a category of super miniature (body size ca. 1 mm or less), poorly known, araneoid spiders that contains eight genera and 74 documented extant species (WSC 2020;Li 2020), but no fossil species have been recorded to date (Dunlop et al. 2020). With the exception of Antarctica, they are found on all continents and some oceanic islands, distributed in the tropical and subtropical regions. They are cryptozoic, commonly found in the leaf litter layer of forests, and some species inhabit dark caves (Cardoso and Scharff 2009;Miller et al. 2014).
Crassignatha Wunderlich, 1995 was erected as a monotypic genus and originally placed in Synaphridae Wunderlich, 1986. The phylogenetic analysis of Lopardo and Hormiga (2015) corroborated its placement within Symphytognathidae. Since its inception, the genus has included nine described species, which are only found in the Gaoligong Mountains of southwest China (Miller et al. 2009), Malaysia (Wunderlich, 1995;Miller et al. 2014). The distribution of Crassignatha is currently confined to Southern China and Southeast Asia. There has been no worldwide or regional taxonomic revision of the genus.
From 2006 to 2018, we have accumulated a considerable number of symphytognathid specimens during many field collecting trips in China, Vietnam, Thailand, Myanmar, and Indonesia. Some of these specimens were described as new species Lin et al. 2013;Lin 2019). However, further morphological and molecular studies of this material have revealed an extraordinary species diversity in the aforementioned geographic areas.
The main aim of this paper is to provide a comprehensive overview of Crassignatha and to report 22 species which are found in Southern China and the Indo-China Peninsula. The circumscription and diagnosis of Crassignatha are reconfirmed. Thirteen species are described and designated as new members of Crassignatha, as well as three new combinations that are transferred from Patu Marples, 1951. The types of seven known Crassignatha species from the Gaoligong Mountains in Southwest China are re-examined. A key and distribution records are provided for all Crassignatha species.

Materials and methods
Most of the specimens from this study were collected by hand or sifting leaf litter and immediately preserved in a 95% ethanol solution. Type specimens of other known Chinese Crassignatha species were borrowed from the Life College of Sciences, Hunan Normal University in Changsha (HNU), China and the Institute of Zoology, Chinese Academy of Sciences in Beijing (IZCAS), China. All materials were examined using a Leica M205 C stereomicroscope and photographed with a Canon EOS 60D wide zoom digital camera (8.5 megapixels) mounted on an Olympus BX 43 compound microscope. Male palps and epigynes were examined and photographed after dissection. The left palp was photographed and described unless it is missing, then the right was selected. Epigynes were treated with lactic acid before being embedded in Hoyer's gum to take photos of the vulva. The images were montaged using Helicon Focus 3.10 (Khmelik et al. 2006) image stacking software. All measurements are in millimeters. Leg measurements are given as follows: total length (femur, patella, tibia, metatarsus, and tarsus).
Tissue samples were taken from twenty-eight individuals of Crassignatha, including eleven new and six known species. Molecular data were obtained from specimens collected at the type locality, 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 and to confirm identifications and sex pairing accuracy.
Abbreviations used in the text or figures are given in Table 1. References to figures in the cited papers are in lowercase ( fig. or figs), figures in this paper are noted with an initial capital (Fig. or Figs). New sequences generated for this study are available in GenBank, and the accession numbers are reported in Table 2. With the exception of the types of previously described species kept in HNU and IZCAS, all molecular vouchers are tentatively deposited in NHMSU in Chengdu, China, and examined morphological material is deposited in NHMSU and IZCAS.  Simon, 1905 by the chelicerae fused near the base vs. unfused. (The latter is tentatively placed in Symphytognathidae (Plantnick and Forster 1989: 76)). Crassignatha differs from Globignatha Balogh &Loksa, 1968 andSymphytognatha Hickman, 1931 by the chelicerae fused only near the base vs. almost fully fused in the latter two (Balogh and Loksa 1968: fig. 10;Forster and Platnick 1977: fig. 41; Lin 2019: fig. 1H). Crassignatha is most similar to Curimagua Forster &Platnick, 1977 andPatu Marples, 1951 in habitus features and body size but differs from Curimagua by having six eyes in diads and lacking female palps rather than eyes in triads and female palps reduced to remnants but not absent (Fig. 1A, D vs. Forster and Platnick 1977: figs 40, 63); and from Patu by the sculptured carapace (Fig. 16A, D;Wunderlich 1995: fig. 15; smooth in a few species) and the male abdomen usually with a lateral scutum ( Fig. 1C; absent in a few species). Description. Body length 0.50-0.90 in male, 0.60-1.30 in female; six eyes in three diads. Ocular area in male raised more than in female. Carapace sub-rounded or pear shaped, brown or yellow-brown, usually sculptured on surface, but smooth in a few species. Cervical groove distinct. Clypeus concave. Chelicerae usually fused near base, with one or two retromarginal teeth. Labium triangular or semilunar, fused to sternum. Sternum scutellate or heart shaped, slightly plump, surface mostly sculptured, rarely smooth, truncated posteriorly. Legs pale yellow to brown-yellow. Leg formula: I-II-IV-III or I-VI-II-III. Male tibia II usually with two long clasping spurs on ventral-subdistal part (but only one spur in a few species). Abdomen globular or quadrate posteriorly in both sexes, male usually with weakly sclerotized abdominal scutum laterally and posteriorly (absent in few species), with an annular plate around spinnerets. Colulus absent.
Male palps oblate. Cymbium wraps around bulb on the prolateral-ventral surface, with a distal cymbial tooth. Median apophysis present, conductor absent. Embolus sclerotized, usually attached to a transparent embolic membrane at base.
Female genital area weakly sclerotized, internal structure faintly visible through tegument. Majority of species with protruded scape, copulatory opening located at apex of scape. Paired spermathecae globular, separated. Copulatory ducts tortile, usually connected to the posterolateral or dorsal surface of spermathecae. Fertilization ducts usually starting at the posterior or lower inner surface of spermathecae.
Epigyne ( Fig. 2D-G): epigynal area weakly sclerotized, with some setae. Scape distinctly extends beyond the epigastric furrow. Internal structures more or less visible via translucent tegument. Spermathecae separated by 1.2× their diameter. Fertilization ducts starting at posterior of spermathecae. Copulatory ducts long, connected to dorsal surface of spermathecae, forming four turns before curving downward. Subproximal copulatory ducts parallel, throughout the entire scape. Copulatory opening located at end of scape.
Epigyne (  Copulatory opening small, located at end of scape. Copulatory ducts long, connected to posteriorly ventral surface of spermathecae, twisted 4× under spermathecae. Bilateral copulatory ducts merged into a Y-shaped atrium before copulatory opening. Male. Unknown. Taxonomic justification. Although we were unable to obtain molecular data for this species, the configuration of the vulva and the modified habitus leave little doubt that it is a member of the genus Crassignatha and not Patu. Therefore, we propose a new combination, Crassignatha bicorniventris   Diagnosis. Crassignatha changyan sp. nov. is similar to C. xichou sp. nov. but differs by the copulatory ducts diagonally linked to the copulatory opening but vertically linked in the latter (Fig. 5E, F).
Epigyne (Fig. 5D-F): epigynal area with a few setae. Scape knobbed. Paired spermathecae globose, widely separated by at least 1.5× their diameter. Copulatory ducts connected to ventral center of spermathecae, twisting into an S-shaped under spermathecae, and merging anteriorly with copulatory openings. Copulatory openings located below scape. Fertilization ducts starting at inside margin of spermathecae, then curving posteriorly.
Male. Unknown. Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. China (Yunnan) (Fig. 38).  Diagnosis. This species is similar to C. gucheng sp. nov. but can be distinguished by the copulatory ducts twisted once in the center of vulva vs. twisted twice in the latter (Fig. 6F, G).
Epigyne (Fig. 6D-G): epigynal area distinctly sclerotized, bears a few setae. Scape large, finger-like, extended beyond the epigastric furrow. Internal structures faintly visible via the translucent tegument. Spermathecae separated by their diameter. Copulatory ducts long, connected to the dorsal center of spermathecae, curving downwards and going up to the center of vulva, then turning back vertically downward, merged before copulatory opening. Copulatory opening located at scape end. Fertilization ducts starting at inside lower margin of spermathecae, then curved posteriorly and laterally.
Male. Unknown. Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. Vietnam (Fig. 38). Diagnosis. The male of C. ertou is similar to that of C. rostriformis sp. nov. but can be distinguished by the narrower embolic base, wider in the latter (Fig. 8A). The female of C. ertou is most similar to C. yinzhi but differs by the copulatory ducts having four sharp turns, but only two in the latter (Fig. 8D-G).

Crassignatha ertou
Description. See Miller et al. (2009). Distribution. China (Yunnan) (Fig. 38). The male of C. gucheng sp. nov. is similar to that of C. pianma and C. quanqu but can be distinguished by the narrower embolic base and spine-like cymbial tooth vs. a wider embolic base and spur-like cymbial tooth in the latter two (Fig. 10A).
The female of C. gucheng sp. nov. differs from that of C. dongnai sp. nov. by the copulatory ducts twisted twice at the center of vulva, only once in the latter (Fig. 10F, G).
Female ( Somatic characters (Fig. 9D-F). Coloration: carapace roughly the same as in male. Legs pale brown. Abdomen with black pigmentation laterally, posteriorly, and ventrally. Prosoma: carapace pear shaped, sculptured, cephalic area slightly lower than in male. PER recurved. Mouthparts and sternum as in male. Abdomen: anteriorly rounded and posteriorly subquadrate, surface with weakly sclerotized hairy patches. Spinnerets as in male.
Epigyne (Fig. 10D-G): epigynal area distinctly sclerotized, bears a few setae. Scape large, finger-like, protruded, copulatory opening located at its terminus. Internal structures faintly visible via translucent tegument. Spermathecae globose, strongly sclerotized,  widely separated by 1.5× their diameter. Fertilization duct originates at medial posterior margin of spermathecae, extends to posterior margin of epigyne. Copulatory ducts long, connected to dorsal surface of spermathecae, extends below spermathecae toward the vulval center, and forms two return paths, then turns downward to copulatory opening.
Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. China (Yunnan), Vietnam (Fig. 38). Diagnosis. Crassignatha gudu can be easily distinguished from other congeners, except C. yamu and C. si sp. nov., by having a columnar atrium formed by the fusion of proximal copulatory ducts (Figs 11F, 31F, 35G). Crassignatha gudu is most similar to C. yamu and C. si sp. nov. and has a similar vulva configuration but differs by the longer copulatory atrium (Fig. 11E, F    comb. nov. but differs by the wider and longer embolic tip and the median apophysis lacks a process, rather than a narrower (Fig. 13A, B), shorter embolic tip and a process on the median apophysis in the latter two (Figs 2A, B, 21A, B). The female of C. mengla sp. nov. is most similar to C. rostriformis sp. nov. in the vulva configuration but can be easily distinguished  Somatic characters (Fig. 12A-C). Coloration: prosoma dark brown. Legs brownyellow. Abdomen charcoal gray, darker ventrally than dorsally. Prosoma: carapace sub-rounded, surface rough, sculptured. Cephalic area elevated. ALE protruded, PER strongly recurved. Clypeus concave. Mouthparts strongly sclerotized. Labium  semicircular. Sternum heart shaped, slightly plump, surface rough, truncated posteriorly. Legs: tibia II with two clasping spurs subdistal-ventrally. Abdomen: nearly rounded dorsally, with lightly sclerotized dots dorsally. Lateral scutum weakly sclerotized, dark brown. Spinnerets brown, with a circular plate.
Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. China (Yunnan) (Fig. 38). Diagnosis. Crassignatha nantou sp. nov. differs from other congeners, except C. shunani sp. nov., by the long, spiral embolus with a sharp, narrow tip and the separate bases of copulatory ducts (Fig. 15A, B, F, G). It is similar to C. shunani sp. nov. by the shape of the male palp and vulva, but the male can be distinguished by having a blunt cymbial tooth and a hook on the median apophysis vs. a sharp cymbial tooth and lack of a hook in the latter (Figs 15A, 29A); the female differs by the closer spermathecae and larger copulatory opening (Figs 15F, G, 29F Somatic characters (Fig. 14A-C). Coloration: carapace, sternum, chelicerae, endites, and labium dark brown. Abdomen blue-green with irregular sclerotized patches. Prosoma: carapace nearly rounded, surface granular, with small sulci. Cephalic region strongly elevated. ALE protruded, PER recurved. Clypeus concave. Chelicerae covered with setae anteriorly. Labium semilunar, fused to sternum. Sternum heart shaped, flat, surface rough, truncated posteriorly. Legs: tibia II with one clasping spur. Abdomen: subelliptic dorsally, with lateral scuta. Spinnerets weakly sclerotized, with a circular plate.  Palp (Fig. 15A-C): pale, weakly sclerotized. Cymbium large, with a few setae distally, cymbial tooth near distal margin. Tegulum large, smooth, and plump. Median apophysis disciform, with a hooked process on margin. Embolic membrane slender, laminar, translucent, arises near anterior part of median apophysis. Embolus long, flexible, spiraled, and wide basally, narrow distally.
Epigyne (Fig. 15D-G): epigynal area lightly sclerotized, with setae on lateral margins. Scape short, wide, copulatory opening located at its terminus, split into two labella. Internal structures more or less visible via translucent tegument. Paired spermathecae globose, separated by half their diameter. Fertilization ducts thin, starting at inside central margin of spermathecae, bent downward, twisted, and furcate at end. Copulatory ducts thick, connected to posterior margin of spermathecae, passing under the spermathecae, up into the center of vulva, deflexed to copulatory opening, their proximal base unfused.
Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. China (Taiwan) (Fig. 38). The male of C. nasalis sp. nov. is similar to that of C. rostriformis sp. nov. but can be distinguished by the sharp hook of the median apophysis and a straight cymbial tooth vs. a blunt hook of the median apophysis and a hook-like cymbial tooth (Figs 17A, B, 25A, B). The female is similar to C. quanqu in epigyne shape but differs from the latter by the indistinct scape and the copulatory ducts nearly forming a closed rhombic area at center of vulva vs. obvious scape and copulatory ducts not forming a closed area at center of vulva (Fig. 17E, F vs. Fig. 23D, E).
Somatic characters (Fig. 16D-F). Coloration: prosoma and legs as in male. Abdomen dark, with tiny light yellow dots. Prosoma: carapace nearly pear shaped, ocular arrangement and modification as in male. Cephalic area lower than in male. PER straight. Mouthparts and sternum as in male. Abdomen: globular dorsally. Spinnerets weakly sclerotized.
Epigyne (Fig. 17D-F): epigynal area distinctly sclerotized, with a few setae. Scape short, strongly sclerotized. Copulatory openings separated, resembling a pig snout. Vulva visible via translucent tegument. Paired spermathecae separated by less than ½ their diameter. Fertilization ducts originate inside posterior edge of spermathecae, curving toward center of spermathecae. Copulatory ducts connected to dorsal center surface of spermathecae, twisting 3 ×, then forming a nearly closed rhombic area in center of vulva.
Etymology. The specific epithet is a Latin adjective (= nasal) and refers to the shape of the copulatory openings of the epigyne.
Distribution. China (Sichuan) (Fig. 38). Diagnosis. The male of C. pianma is similar to C. quanqu in the form of the palp but can be distinguished from the latter by the subquadrate median apophysis with a hooked process, rather than a subtriangular median apophysis with a truncated process (Figs 19A, B, 23A, B). The female of C. pianma seems closest to that of C. bangbie sp. nov. but differs by the more slender, more twisted copulatory ducts than in the latter, and the smaller copulatory openings (Figs 19E-G, 3E-G).

Crassignatha pianma
Description. See Miller et al. (2009). Distribution. China (Yunnan) (Fig. 38).   Diagnosis. This species differs from other congeneric species except C. baihua sp. nov. by the short, stiff embolus (Fig. 21A, B). It is most similar to C. baihua sp. nov. in the form of the palp and the vulva configuration but can be easily distinguished by the sloped embolic apex, rather than flat as in the latter, and by having six twists of the copulatory ducts, rather than four in the latter (Figs 21A, B, F, G, 2A, B, F, G).
Female ( Somatic characters (Fig. 20D-F). Coloration: prosoma and legs as in male. Abdomen dorsally darker than in male, ventrally lighter. Prosoma: modification and arrangement of eyes as in male, cephalic area lower than in male. Clypeus slightly concave. Mouthparts and sternum as in male. Abdomen: anteriorly round and posteriorly square, surface bears sparse, long setae, lateral scutum and circular plate absent. Spinnerets slightly sclerotized.
Epigyne (Fig. 21D-F): epigynal area weakly sclerotized, bears a few setae. Scape developed, protruded, longer than wide. Copulatory openings located at terminus. Internal structures faintly visible via translucent tegument. Paired spermathecae globose, widely separated by at least 1.5× their diameter. Fertilization ducts originating from the lower inside margin of spermathecae, bent downwards and laterally. Copulatory ducts long, connected to dorsal surface of spermathecae, from below spermathecae to the center of vulva, making six bends, then reaching copulatory openings.
Taxonomic justification. The shape of the male palps, the configuration of the epigyne, the modified carapace, and the male abdominal scutum and clasping spurs on tibia II leave no doubt that this species is a member of Crassignatha and not Patu. Therefore, we propose a new combination, C. quadriventris ) comb. nov., transferring it from Patu.
Distribution. China (Hainan) (Fig. 38). Diagnosis. The male of Crassignatha quanqu is similar to C. gucheng sp. nov. but can be distinguished by the median apophysis with two tapered distal processes and the details of the palp (Fig. 23A-C vs. Fig. 10A-C). The female of C. quanqu is similar to C. yinzhi and C. thamphra sp. nov. in the vulva configuration, but differs by the nearly vertical connection of copulatory ducts and copulatory openings, rather than connected diagonally as in the latter two, and differs by the fertilization ducts starting at the posterior margin of the spermathecae, rather than the inside medial margin as in the latter two (Fig. 23D, E vs. Figs 32F, G, 37F, G).

Crassignatha quanqu
Description. See Miller et al. (2009). Distribution. China (Yunnan) (Fig. 38). 6.VIII.2010, Z. Yao, X. Wang and C. Wu leg.; 2♂ 16♀ (NHMSU-HA078), 3♂ 2♀ (NHMSU-HA103), same data as holotype; 1♂ (NHMSU-HA079) and 1♀ (NHM-SU-HA079) used for sequencing, GenBank: MT991998 and MT991997, same data as for preceding. Diagnosis. The male of C. rostriformis sp. nov. is similar to C. nasalis sp. nov. in the form of the palp but differs from the latter by the large, hooked cymbial tooth and the wider embolic base (Fig. 25B vs. Fig. 17A, B). The female is most similar to that of C. mengla sp. nov. in the vulva configuration but can be easily distinguished by spermathecae separated by less than their diameter, and the low second turn of the copulatory duct, rather than wide intervals of spermathecae and the high second turn of the copulatory duct (Fig. 25D-F vs. Fig. 13F, G).
Epigyne (Fig. 25D-F): slightly sclerotized, with a few setae at lateral margins. Scape short, slightly protruded. Copulatory openings large, flat, beak shaped, located at the terminus of scape. Internal structures faintly visible via translucent tegument. Spermathecae globose, separated by ~0.8× their diameter. Fertilization ducts starting at inside posterior margin of spermathecae and bending below the venter of spermathecae. Copulatory ducts relatively long, connected to lower dorsal surface of spermathecae, bypassing around spermathecae, forming three bends, fusing before copulatory openings.
Etymology. The specific epithet is derived from the Latin adjective rostriformis (rostriform), in reference to the shape of the copulatory openings.
Distribution. China (Yunnan) (Fig. 38). (  Diagnosis. This species differs from all other species of Crassignatha by the long embolus coiling into two loops (Fig. 27A) and by the long copulatory ducts connected to the anterolateral margin of the spermathecae, coiled into three loops below spermathecae (Fig. 27D, E). Its dorsoventral dichroism is also a prominent feature (Fig. 26A-D).

Crassignatha shiluensis
Description. See . Taxonomic justification. A series of combinations: the form of the male palp and the configuration of the epigyne, the chelicerae fused at the base, and the male clasping setae distoventrally on tibia II suggest that this species is more similar to Crassignatha than Patu. It shares homologous characters of Crassignatha, such as a large median apophysis on a slightly oblate male palpal bulb and globular spermathecae rather than a nearly oviform male palpal bulb and claviform spermathecae as in Patu. Thus, we propose a new combination, Crassignatha shiluensis   Diagnosis. This species is similar to C. nantou sp. nov. in the form of the male palp and the vulva configuration but can be distinguished by having a sharp cymbial tooth and lacking a hooked process on the median apophysis (Fig. 29A vs. Fig. 15A), and by the more widely separated spermathecae and lower inflection point of the copulatory ducts in the center of the vulva (Figs 29F, 15G).
Female (   Somatic characters (Fig. 28D-F). Coloration: prosoma and legs as in male. Abdomen black, with sclerotized dots dorsally. Prosoma: carapace pear shaped, surface modification and arrangement of eyes as in male. Cephalic area lower than in male. Mouthparts and sternum as in male. Abdomen: globular. Spinnerets tiny, lacking circular plate.
Epigyne (Fig. 29D-G): epigynal area slightly sclerotized. Scape protruded, as wide as long. Copulatory openings located at terminus of scape. Internal structures faintly visible via translucent tegument. Spermathecae strongly sclerotized, separated by their diameter. Fertilization ducts originating posteromedially from spermathecae. Copulatory ducts long, connected to posterior margin of spermathecae, curved upward and inward to center of vulva, then turned sharply downward to copulatory openings. The base of copulatory ducts unfused.
Etymology. The specific name is from the Chinese pinyin shŭ nán, referring to the collection locality of this new spider species from southern Sichuan; noun in apposition.
Epigyne (Fig. 31D-F): epigynal area lightly sclerotized. Scape slightly protruded, as wide as long. Internal structures faintly visible via translucent tegument. Paired spermathecae separated by their diameter. Fertilization ducts slender, starting at the inside medial margin of spermathecae. Copulatory ducts long and extremely tortuous, connected to posterior margin of spermathecae, extending from under spermathecae to venter, forming two open loops, curving upward to center of vulva, then fusing into a columnar atrium that reaches copulatory opening at scape terminus.
Etymology. The specific name is derived from the Chinese pinyin word for "spiral" (si), referring to the shape of the embolus, and is a noun in apposition.
Epigyne (Fig. 32D-G): epigynal area slightly sclerotized, bears a few long setae. Scape protruded, longer slightly than wide. Internal structures faintly visible via translucent tegument. Spermathecae separated by ~ ½ their diameter. Fertilization ducts thin, slender, originating from posteromedial margin of spermathecae, forming a U-shape. Copulatory ducts long, connected to the posterior surface of spermathecae, curving twice below spermathecae, linked diagonally, and fused to copulatory opening.
Male. Unknown. Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. Thailand (Fig. 38). Diagnosis. This new species can be easily distinguished from all species of Crassignatha by the lack of a scape, the fertilization ducts starting at the posterolateral margin of the spermathecae, the copulatory ducts connecting to the anterolateral margin of spermathecae, fusing into an H-shaped atrium above copulatory opening (Fig. 33E, F).
Male. Unknown. Etymology. The specific name is derived from the type locality; noun in apposition. Distribution. China (Yunnan) (Fig. 38).

Diagnosis.
The male of C. yamu is most similar to that of C. haeneli, C. danaugirangensis, and C. shiluensis in the form of the palp and the long, linear embolus but differs from C. haeneli and C. danaugirangensis by the spiral embolus on the ventral portion of the palpal bulb (Fig. 25B vs. Wunderlich 1995: figs 18, 19;Miller et al. 2004: fig. 4); from C. shiluensis by having fewer loops of the embolus (Fig. 35B vs. Fig. 27A). The female is similar to that of C. gudu and C. si in vulva configuration and the course of the copulatory ducts but can be easily distinguished by having the columnar atrium longer than in C. gudu and shorter than in C. si (Fig. 35G vs. Figs 11F, 31F).
Description. See Miller et al. (2009). Distribution. China (Yunnan) (Fig. 38).    Table A1. Uncorrected genetic pairwise distance (below diagonal) and standard error (above diagonal) of a partial fragment of COI from the seventeen species