Redescription of types of three species of Leptonetidae Simon, 1890 from China (Arachnida, Araneae)

Abstract Three species of the genus Leptoneta Simon, 1872 deposited at Hunan Normal University, Changsha, China, are examined and redescribed. Two species are transferred from Leptoneta Simon, 1872 to Leptonetela Kratochvíl, 1978, and the following new combinations are proposed: Leptonetela trispinosa (Yin, Wang & Wang, 1984), comb. nov. (♀♂), and Leptonetela unispinosa (Yin, Wang & Wang, 1984), comb. nov. (♂). The generic placement of Leptoneta monodactyla Yin, Wang & Wang, 1984 is maintained. Detailed descriptions, illustrations, and a distribution map for all three species are provided.


Introduction
Leptonetids are small in size, usually less than 3 mm, with the body color entirely pale or yellowish (sometimes color varying between pale and yellowish) (Lin and Li 2010;Le Peru 2011). Leptoneta Simon, 1872, the type genus, comprises 68 species and is the second largest genus in the family (the genus Leptonetela Kratochvíl, 1978 is the largest with 108 species) (WSC 2020). The first Leptoneta species reported from China was Leptoneta huanglongensis Chen, Zhang & Song, 1982, which was collected from a cave. To date, 22 Leptoneta species have been described from China (Chen et al. 1982(Chen et al. , 1984(Chen et al. , 1986(Chen et al. , 2000(Chen et al. , 2010Yin et al. 1984Yin et al. , 2012Song and Xu 1986;Song and Kim 1991;Chen and Zhang 1993;Zhu and Tso 2002;Chen and Zhu 2008;Tong and Li 2008;WSC 2020). We reexamined all of the type specimens deposited in Hunan Normal University which were originally described as members of Leptoneta, including Leptoneta monodactyla Yin, Wang & Wang, 1984, Leptoneta trispinosa Yin, Wang & Wang, 1984, and Leptoneta unispinosa Yin, Wang & Wang, 1984. Males of Leptoneta trispinosa and Leptoneta unispinosa have characteristics of the genus Leptonetela, including strong palpal femoral spines absent (Figs 6A, 8C) and large palpal tibial spurs present (Figs 6B, 8D) (Lin and Li 2010;Wang and Li 2011). In this work, we transfer both species to the genus Leptonetela: Leptonetela trispinosa (Yin, Wang & Wang, 1984) comb. nov. and Leptonetela unispinosa (Yin, Wang & Wang, 1984) comb. nov. The number of the known Leptoneta and Leptonetela species from China changes from 20 and 98, respectively, to 22 and 96.

Materials and methods
All specimens examined in this study are deposited in the College of Life Sciences, Hunan Normal University (HNU). Specimens were examined using an Olympus SZX16 stereomicroscope and an Olympus BX53 compound microscope. Photographs were taken with a Canon PowerShot G12 digital camera mounted on an Olympus BX53 compound microscope. Female genitalia were cleaned with lactic acid before being photographed. Both the male palp and female genitalia were examined, photographed, and illustrated after dissection. The data in original description was kept unaltered. Eye diameters were taken at the widest point. Leg measurements are given as total length (femur, patella, tibia, metatarsus, tarsus). Leg segments were measured on their dorsal sides. All measurements are in millimeters (mm). The left palpi and chelicerae of male spiders are illustrated, except where otherwise indicated.
Male palp as illustrated in Figs   with distal special apophysis (TA) and distal spine retrolaterally. TA clavate, gradually more transparent from base to tip, with small spine on its tip (Fig. 2B). Tarsus slightly sunken and contracted at middle position, with one distal long spine, three long dorsal spines, two long retrolateral, and two long prolateral spines on distal half, and one long dorsal spine on basal half ( Female. Unknown. Distribution. Only known from the type locality, Hunan, China (Fig. 9). Remarks. According to Platnick (1986Platnick ( , 2007 and Le Peru (2011), all Leptoneta species are limited to the western Mediterranean region and all those from outside the Mediterranean region are probably misplaced. Also, as stated by Tong and Li (2008), the Chinese Leptoneta species should probably be included in one or more new genera. The original designation of Leptoneta monodactyla Yin et al., 1984 is retained in this work pending comprehensive revisionary work.
Type locality. Koutouki Cave near Ljopessi, Greece. Diagnosis. The male of Leptonetela trispinosa (Yin et al., 1984) comb. nov. is similar to those of Leptonetela hangzhouensis (Chen et al., 1984) and Leptonetela microdonta (Xu & Song, 1983) in having the median apophysis fork-shaped and a similar arrangement of spines on the retrolateral palpal tibia (compare Figs 4B, 6D with Wang and Li 2011: figs 13B, D, 28B, D), but differs from L. hangzhouensis by the shape of the teeth on the median apophysis (the middle two teeth ca half of the lateral two in length in this species vs ca one-third in L. microdonta) (compare Fig. 4B with Wang and Li 2011: fig. 13B), and from L. microdonta by the number and shape of teeth on the median apophysis (four teeth, the middle two teeth ca half of the lateral two in length in this species vs five teeth, the middle three teeth very small, shorter than one fourth of the lateral two in L. microdonta) (compare Figs 4B, 6D with Wang and Li 2011: figs 28B, D). The female of Leptonetela trispinosa can be distinguished from that of Leptonetela microdonta by the different twisting of the spermathecae (compare Fig. 5E with Wang and Li 2011: fig. 29C, D).
Description. Holotype Male. Body (Fig. 4A) length 1.80, carapace 0.80 long, 0.80 wide, abdomen 1.00 long, 0.73 wide (data from original description by Yin et al. 1984: 364). Carapace yellow brown (Fig. 4A). Six eyes, ALE, and PLE connected to each other by the black bases, PME separated from ALE and PLE. Thoracic median groove short, brown, needle-shaped. Cervical grooves and radial furrows brown, indistinct. Chelicerae tawny, with eight promarginal (teeth gradually becoming smaller and denser from the distal end to the base of chelicera) and four small retromarginal teeth (Fig. 6D) Yin et al. 1984: 364). Abdomen pale brown, oval, lacking distinct patterns (Fig. 4A). Male palp as illustrated in Figs 4B-D, 6A-C. Femur without strong spines. Patella with a small spine dorsally. Trichobothria not found on the dorsal tibia, although they are usually present in the other congeneric species; it is very possible that trichobothria have detached from the body and been lost. Tibia with one seta and five spines retrolaterally (three very strong spines in longitudinal row, other two near distal end of tibia obviously shorter and thinner). Tarsus slightly sunken and contracted at middle resulting in formation of earlobe-shaped process distally (Fig. 4D); one distal spine, one ventral long spine, one long retrolateral  (Yin et al., 1984), comb. nov., holotype male A habitus, dorsal view B palpal bulb, ventral view C palp, prolateral view D palp, retrolateral view.  (Yin et al., 1984), comb. nov., paratype female A carapace, dorsal view B abdomen, dorsal view C habitus, dorsal view D habitus, ventral view E vulva, dorsal view. Abbreviations: At, atrium; SS, spermathecae stalk; SH, spermathecae. spine, and one long prolateral spines present on distal half of tarsus (Figs 4C, D, 6A, B). Palpal bulb oval, smooth. Conductor lamellar, membranous, and slightly wide. Embolus membranous, broad, with the distal part slightly curled towards base (Fig. 6C). Median apophysis fork-shaped, with four teeth, lateral two strong and middle two smaller (Figs 4B, 6C). Prolateral lobe medium-sized, elliptical (Fig. 6A).
Distribution. Only known from the type locality, Hunan, China (Fig. 9). Note. Because of the poor quality of the images in all available references to the female of L. hangzhouensis the females of these two species cannot be compared. (Yin, Wang & Wang, 1984), comb. nov. Figures 7, 8 Leptoneta unispinosa Yin et al. 1984: 368, fig Diagnosis. The male of Leptonetela unispinosa (Yin et al., 1984), comb. nov. is similar to that of Leptonetela quinquespinata (Chen & Zhu, 2008) in having an Ashaped median apophysis and the embolus curved distally (compare Fig. 8A with Wang and Li 2011: fig. 47D), but differs by the number of eyes (six eyes in this species vs eyes completely absent in Leptonetela quinquespinata) and the arrangement of spines on the retrolateral tibia ( five spines including three in a longitudinal row and two in a transverse line in this species vs six spines almost in a longitudinal row in Leptonetela quinquespinata) (compare Figs 7A, 8D with Wang and Li 2011: fig. 44A, D).
Male palp as illustrated in Figs 7C-E, 8A, C, D. Femur without any strong spines. Patella with dorsal spine distally. Trichobothria not to be found on dorsal tibia, although usually present in other congenerics (it is very possible that trichobothria were  (Yin et al., 1984), comb. nov., holotype male A carapace, dorsal view B abdomen, dorsal view C palpal bulb, ventral view D palp, prolateral view E palp, retrolateral view.  (Yin et al., 1984), comb. nov., holotype male A palpal bulb, ventral view B chelicera, retrolateral view C palp, prolateral view D palp, retrolateral view. Abbreviations: Co, conductor; E, embolus; MA, median apophysis; PL, prolateral lobe; TS, tibial spur. broken off body and lost). Tibia with one long thin prolateral spine basally and five retrolateral spines (three spines arranged in longitudinal row along tibia, first one near basal end especially strong; other two arranged in transverse line along distal margin of tibia). Tarsus sunken and contracted slightly at middle position resulting in forming earlobe-shaped process distally (Fig. 8D). One distal short spine, one ventral long spine, one long retrolateral spine, and one long prolateral spine present on distal half of tarsus (Figs 7D, E, 8C, D). Palpal bulb oval, smooth. Conductor lamellar, membranous, slightly wide. Embolus membranous, slightly twisted towards the prolateral side. Median apophysis A-shaped (Figs 7C, 8A). Prolateral lobe medium-sized, elliptical (Fig. 8C).

Discussion
The family Leptonetidae comprises 353 species belonging to 21 genera worldwide. Only three genera, Leptoneta, Leptonetela, and the monotypic genus, Rhyssoleptoneta Tong & Li, 2007, are distributed in China (WSC 2020. Chinese Leptoneta species have diverse morphological characteristics of the male palp and Tong and Li (2008) thought that they should probably be included in one or more new genera. Tong and Li divided Chinese Leptoneta species (excluding Leptoneta arquata Song & Kim, 1991, a species for which only the female known) into four species groups, Leptoneta maculosa group, Leptoneta huanglongensis group, Leptoneta microdonta group, and Leptoneta miaoshiensis group. The Leptoneta microdonta group consisted of six species and is characterized by the presence of strong spines ventrally on the male palpal tibia (Tong and Li 2008). Three species of the Leptoneta microdonta group have been transferred to the genus Leptonetela by Wang and Li (2011) and two species are being transferred in the present study. Judging from the characteristics of the male palpal tibia and femur shown in the figures of Chen et al. (2000), we think that Leptoneta xui Chen, Gao & Zhu, 2000, the only one remaining in the L. microdonta group, should also be a member of the genus Leptonetela and that the Leptoneta microdonta group should be dropped entirely.
The genus Leptonetela is mainly distributed in China. Nighty-eight species (including two new combinations in the current study) are described from China and only 12 from regions outside China including nine from Greece, one from Vietnam, one from Turkey and one from the Caucasus.
The quick increase of the number of Chinese Leptonetela species is mainly due to two excellent studies: Wang and Li (2011) and Wang et al. (2017). Twenty-seven and 46 new species were reported by Wang and Li (2011) and Wang et al. (2017), respectively. With three exceptions (Leptonetela pungitia Wang & Li, 2011;Leptonetela trispinosa;Leptonetela unispinosa), nearly all Chinese Leptonetela species are endemic to either a single cave or a cave system (Wang et al. 2017;He et al. 2019;WSC 2020). Study of additional caves in China may result in the discovery of more undescribed caveassociated Leptonetela species, but this still needs to be confirmed by future collecting.