On the linyphiid spiders from Thailand and West Malaysia (Arachnida: Aranei: Linyphiidae)

The linyphiid spiders from Thailand and West Malaysia kept at the Museum d'histoire na- turelle de Geneve are studied. Three new genera and nine new species are described: Aperturina gen.n. (the type species: A. paniculus sp.n.), Apophygone gen.n. (the type species: A. simpulum sp.n.), Lamellasia gen.n. (the type species: L. mirabilis sp.n.), Asiagone siama sp.n., Batueta baculum sp.n., Nasoonaria magna sp.n., Oedothorax converter sp.n., Theoa elegans sp.n., and T. longicrusa sp.n. Twelve linyphiid species are re- corded as new to the fauna of Thailand: Atypena cirri- frons (Heimer, 1984), Batueta voluta Locket, 1982, Erigone prominens Bosenberg et Strand, 1906, Hy- lyphantes graminicola (Sundevall, 1830), "Linyphia" chiridota (Thorell, 1895), Microbathyphantes palmar- ius (Marples, 1955), Nasoona crucifera (Thorell, 1895), Nasoonaria sinensis Wunderlich et Song, 1995, Ne- riene oxycera Tu et Li, 2006, Parameioneta spicata Locket, 1982, Tapinopa vara Locket, 1982 and Theoa tricaudata (Locket, 1982). Three linyphiid species, Gongylidioides pectinatus Tanasevitch, 2011, Nasoona crucifera and Plectembolus quinqueflectus Millidge et Russell-Smith, 1992, are newly recorded from West Malaysia. Based on the new data, the spider faunas of Thailand and West Malaysia are known to contain 43 and 24 linyphiid species, respectively.


Introduction
The linyphiid faunas of Thailand and West Malaysia are among the best studied ones in continental SE Asia, comprising 22 and 19 species respectively. Such a relative progress is mostly due to the studies by Locket [1982], Millidge & Russell-Smith [1992] and Millidge [1995], who in total have described some 30 new taxa of Linyphiidae from the area at hand. Recently, a new paper on the Laotian linyphiids describing two new genera and six species has been published [Tanasevitch, 2014]. Some of the species described in the latter paper also occur in Thailand and Malaysia, which is understandable due to geographical closeness of the territories studied and a high vagility of the group.
Studies on the SE Asian linyphiids still proceed at the alpha-taxonomy level (descriptions of new species and genera), though it is already clear that the regional fauna of this basically boreal group is in fact extraordi-narily rich and peculiar. Many taxa of the Oriental linyphiids possess the amazingly complex structure of copulative apparatus, as well as diverse forms and sizes of the genital sclerites. Therefore, it is rather difficult to compare them to similar or related taxa from the neighboring Palearctic fauna, resulting in descriptions of numerous new monotypic genera. At the same time, the poor knowledge of SE Asian linyphiids allows one to suspect that due to the finding of new species from both the mainland and insular parts of the vast Oriental Region the monotypic genera will become at least oligotypic ones, and the connections of this evidently autochthonous aboriginal fauna with those of other large zoogeographic regions will become clearer. This is the second paper of mine on the SE Asian linyphiids devoted to the fauna of Thailand and West Malaysia. The aim is to describe three monotypic genera and nine new species. As a result, two of the previously described monotypic genera have been become oligotypic ones: viz., Asiagone Tanasevitch, 2014 andNasoonaria Wunderlich et Song, 1995. Material and methods This paper is based on the material collected from Thailand and West Malaysia that is kept at the Muséum d'histoire naturelle de Genève, Switzerland (MHNG). If not mentioned otherwise, the material is deposited in the MHNG; some paratypes and non-types are placed to the collection of the Zoological Museum of the Moscow State University, Moscow, Russia (ZMMU). Sample numbers are given in square brackets.
The chaetotaxy of Erigoninae is given in a formula, e.g., 2.2.1.1, which refers to the number of dorsal spines on tibiae I-IV. In Micronetinae, the chaetotaxy is given in a different formula, e.g., TiI: 2-1-1-2(1), which means that tibia I has two dorsal spines, one pro-, one retrolateral spine, and two or one ventral spine (the apical spines are disregarded). The sequence of leg segment measurements is as follows: femur + patella + tibia + metatarsus + tarsus. All measurements are given in mm. Scale lines in the figures correspond to 0.1 mm unless indicated otherwise.
TYPE SPECIES: Aperturina paniculus sp.n. ETYMOLOGY. The genus name refers to the large epigynal aperture; the gender is feminine.
DIAGNOSIS. The new Erigoninae genus is diagnosed by the peculiar structure of copulatory organs in both sexes, as well as by the micronetine-type of chaetotaxy. The male is distinguished by a combination of the following characters: the narrowed distal part of cymbium, the presence of the convector and the long, whip-shaped embolus; by the specific shape of small paracymbium, as well as by the hypertrophied panicle-shaped median membrane. The female is diagnosed by the large fringed aperture, as well as by the narrow coiled receptacula.
DESCRIPTION. Medium-sized erigonines, total length 1.55-1.73. Male carapace somewhat modified, cephalic part slightly elevated, sulci present, eyes normal. Chelicerae weak, without mastidion. Chaetotaxy: all tibiae with two dorsal spines; in addition, tibia I with one pro-and one retrolateral spines, tibia II with a retrolateral spine; spines long and strong. Metatarsi spineless. Each of Mt I-III with a trichobothrium. TmI, 0.25-0.30. Palpal tibia small, unmodified. Distal part of cymbium much narrower than its proximal part. Paracymbium small, simple, pockets absent. Tegulum enlarged, swollen. Distal suprategular apophysis relatively large, of irregular shape. Median membrane panicle-shaped, transparent, well protruding outside palp. Embolus thin and long, whip-shaped. Convector present. Epigyne with the large, shallow, triangular aperture surrounded by a sclerotized swelling interrupted laterally in some places. Abdomen grey to pale grey, without clear dorsal pattern. SPECIES INCLUDED. Only the type species. TAXONOMIC REMARKS. At present, it is not possible to assign the type species to any of the existing genera. Yet, it is unique amongst the typically erigonine genera having the micronetine-type of chaetotaxy such as that of Improphantes Saaristo et Tanasevitch, 1996, Palliduphantes Saaristo et Tanasevitch, 2001, Tchatkalophantes Tanasevitch, 2001. Only a few Erigoninae genera actually possess a prolateral spine on TiI, e.g., Asthenargoides Eskov, 1993, Carorita Duffey et Merrett, 1963, Holminaria Eskov, 1991, Karita Tanasevitch, 2007, Schistogyna Millidge, 1991., but none of them has retrolateral spine(s) on TiI and/or TiII. A transformation of the median membrane into the remarkable structure resembling a panicle also seems to be a unique phenomenon.
TYPE SPECIES: Apophygone simpulum sp.n. ETYMOLOGY. The genus name Apophygone is a combination of the words "apophysis", meaning the peculiar shape of the hypertrophied distal suprategular apophysis, and a part of the generic name "Erigone"; the gender is feminine.
DIAGNOSIS. The new Erigoninae genus can easily be distinguished by the combination of the following characters: the presence of the hypertrophied, ladlelike distal suprategular apophysis and the long, coiled embolus with a hook-shaped tailpiece in the male, and by the semicircular plate of the epigyne and strait entrance ducts in the female.
TAXONOMIC REMARKS. According to Merrett [1963], the strong development of distal suprategular apophysis is a characteristic feature of the Savignia genus-group, specifically of Dactylopisthes Simon, 1884. However, the new genus, besides the hypertrophied distal suprategular apophysis, has nothing in common (including the chaetotaxy formula) with any genus of this group. The taxonomic position of Apophygone gen.n. and its relations within the subfamily Erigoninae remain obscure.
DIAGNOSIS. See above, under the generic diagnosis.
DESCRIPTION. Male (paratype from Umphang). Total length 1.33. Carapace 0.63 long, 0.50 wide, pale brown. Cephalic part elevated, sulci long and narrow, eyes normal (Fig. 8 ETYMOLOGY. The species name is a noun in apposition, referring to Siam, the old name of Thailand.
DIAGNOSIS. The new species is distinguished by the absence of the specific "flag-shaped" chitinous tunic outgrowth of the embolus which is present in the two known congeners, and by the presence of the short threadlike part of the embolus in the male, as well as by the totally covered aperture of the epigyne in the female. TAXONOMIC REMARKS. The species seems to be most similar to Laotian Asiagone signifera Tanasevitch, 2014 known from the male [Tanasevitch, 2014], and can be easily distinguished by the shorter and abruptly truncate palpal tibia, as well as by the absence of the frontal tegular apophysis.
DISTRIBUTION. Known from southern and northern Thailand.
DIAGNOSIS. The new species can be easily distinguished by the presence of the thick, strong palpal tibial seta; by the shape of the posterodorsal cymbial projection in the male, as well as by the translucent, straight, spiral seminal ducts in the female.
REMARKS. The genus Batueta Locket, 1982 is unique by the disposition of setae on leg tibia rather than by its chaetotaxy. In all erigonine representatives having one dorsal seta on tibia, this seta is situated in the proximal part of the segment, whereas in Batueta it is located distally. Most probably, this taxon initially had the chaetotaxy formula 2.2.1.1 but for some reasons the proximal setae on tibiae were lost, and the formula became look as 1.1.0.0 in both sexes. Thus, at present, the only remaining seta both on TiI and on TibII is situated on the distal part of the segment. In the original description of B. voluta Locket, 1982 (the type species), the author mentioned that the chaetotaxy formula was 1.   REMARKS. The species is new to the Thai fauna. DISTRIBUTION. Throughout the Palaearctic Region; in the Oriental Region, it is known from Vietnam [Tu & Li, 2005], Myanmar [Thorell, 1895, as Erigone birmanica Thorell, 1895], Laos [Tanasevitch, 2014] and Thailand.
TYPE SPECIES: Lamellasia mirabilis sp.n. ETYMOLOGY. The generic name Lamellasia is a combination of the words "lamella", meaning "the lamella characteristica", and "Asia"; the gender is feminine.
DIAGNOSIS. The new genus is distinguished by the unique conformation of copulatory organs in both sexes, notably, by the hypertrophied lamella characteristica and the reduced terminal apophysis in the male palp, as well as by the reduced median part of the scape and the unusual arrangement of entrance grooves, which extend to the posterior median plate in the female.
DESCRIPTION. Medium-sized Micronetinae, total length 1.80-2.2. Carapace unmodified, eyes normal. Chelicerae unmodified, stridulatory furrows present, fine. Chaetotaxy: TiI: 2-1-1-0, II: 2-0-1-0, III-IV: 2-0-0-0; MtI-IV: 1-0-0-0, spines long. Metatarsi I-III with a trichobothrium each. TmI 0.18-0.24. Palp (Figs): Patella with a special spine. Tibia and cymbium slightly modified. Paracymbium relatively small, V-shaped. Tegulum relatively large, markedly protruding outside palp. Distal suprategular apophysis and median membrane present but both poorly developed. Radix small, shapeless. Fickert's gland absent. Lamella characteristica large, proximally wide and concave. Terminal apophysis totally reduced. Embolus with small and curved body and thin, straight, thread-like embolus proper. Epigyne with a broad proscape, median part of scape reduced. Entrance grooves relatively thick, extending to posterior median plate. Stretcher presence, lateral lobes reduced. Abdomen variegated, dorsal pattern present. SPECIES INCLUDED. Only the type species. TAXONOMIC REMARKS. Basically, a reduction of the genital sclerites or their parts is not infrequent in Micronetinae, whereas the presence of entrance grooves inside the posterior median plate is unique and has no analogues among the representatives of the subfamily. Usually, the entrance grooves pass inside the scape, then proceed along the lateral walls and end in the receptacles, but never penetrate the posterior median plate. The genus position is unclear, and at present it is impossible to indicate its close relatives.
REMARKS. The species was originally described by Thorell [1895] as Erigone Audouin, 1826 from Myanmar and has been provisionally transferred to Linyphia Latreille, 1804 by Tanasevitch [2010]. The still unknown male makes the taxonomic position of "L." chiridota unclear. It is new to Thai fauna.
REMARKS. The species is new to the Thai and West Malaysian faunas.
DIAGNOSIS. The new species is distinguished by the shape of male carapace, by the peculiar shape of the hypertrophied distal suprategular apophysis, as well as by the well-developed column.
Cymbium without a posterodorsal outgrowth. Paracymbium relatively large, with a massive proximal part, hook-shaped distally. The middle part of distal suprategular apophysis very wide and flat, covering almost all prolateral side of tegulum, its distal part extending to a long spike. Radix very small, connecting to the well-developed column. Embolus thin and long, making a loop; its distal part is embedded into distal suprategular apophysis. Abdomen 1.53 long, 0.85 wide, pale, with a raw of four pairs of grey spots merging posteriorly into narrow transverse stripes.
Female unknown. TAXONOMIC REMARKS. The new species can be easily distinguished from the single congener, N. sinensis Wunderlich et Song, 1995 (see below), by the presence of a globular elevation on male carapace behind the posterior median eyes, as well as by simple shape of the palpal tibia with the single apophysis.
DIAGNOSIS. The new species is distinguished by the peculiar shapes of palpal tibia and paracymbium, as well as by large and complicated convector.

Tapinopa vara
DISTRIBUTION. West Malaysia [Locket, 1982], northern and southern Thailand.  (Locket, 1982), known from the Seychelles [Saaristo, 1995], West Malaysia [Locket, 1982] and Thailand (present data; see below), but clearly differs from it in the presence of two large, widely set apart teeth at the base of the bifid proximal cymbial outgrowth, as well as in by rounded shape of the terminal apophysis.
DISTRIBUTION. Known from the type locality in northern Thailand only. Tanasevitch ETYMOLOGY. From the Latin adjective meaning "long leg" and referring to relatively long legs of the species.

Theoa hamata
DIAGNOSIS. The new species is distinguished by the peculiar shape of proximal outgrowth of the male cymbium, as well as by the shape of the terminal apophysis.
Female. Unknown. TAXONOMIC REMARKS. It is the largest species among its congeners, which size varies within 1.23-1.40 mm. The species can easily be distinguished from other members of the genus by the solid, not divided proximal cymbial apophysis.
DISTRIBUTION. Known from the type locality in southern Thailand only.

Discussion
With the present addition of new taxonomic/faunistic data, the fauna of Thailand contains 43 linyphiid species, and that of West Malaysia 24 species. The vast majority of these species have been described from these regions or known from the neighboring areas of SE Asia. Only two species were recorded also from southern provinces of China: Nasoona crucifera and Nasoonaria sinensis; one species -Microbathyphantes palmarius -is widely distributed in the Oriental Region and Polynesia, whereas only two species display really wide ranges: the Palaearctic Hylyphantes graminicola and the Cosmopolitan Erigone prominens. This pattern of the fauna indicates a high specificity of the linyphiid fauna of SE Asia, its richness and autochthonous origin. Further studies should clarify this matter.
ACKNOWLEDGEMENTS. I am most grateful to all persons whose collections have been used in the present study. Special thanks go to Peter Schwendinger (MHNG, Switzerland) for the opportunity to work with the collections of the MHNG and for his valuable comments on the manuscript.