﻿Three new species of the spider genus Utivarachna Kishida, 1940 (Araneae, Trachelidae) from China and Vietnam

﻿Abstract Three new species belonging to the kinabaluensis group of the trachelid genus Utivarachna Kishida, 1940 are reported from China and Vietnam: U.linyejieisp. nov. (♂♀), U.tamdaosp. nov. (♂♀), and U.zhengguoisp. nov. (♂♀). Type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China and the Vietnam National Museum of Nature (VNMN) in Hanoi, Vietnam.


Introduction
The family Trachelidae Simon, 1897 is a small spider group which currently contains 20 genera and 266 species (Marusik and Fomichev 2020;WSC 2023).It is distributed worldwide but occurs predominately in Africa and the Americas (Rivera-Quiroz and Álvarez-Padilla 2015; Quasin et al. 2018;Ono and Aung 2022;WSC 2023).Of these, only 34 and one known species recorded from China and Vietnam, respectively (Li et al. 2022;Lin et al. 2023;WSC 2023).Trachelid spiders occupy a wide range of habitats in a variety of ecosystems, including under loose bark of trees, in rolled leaves, under stones, in leaf litter, in wood debris, on the forest floor, in marshes, and in houses (Haddad and Lyle 2008;Quasin et al. 2018;González Márquez et al. 2021;Zhang et al. 2022).
Utivarachna Kishida, 1940 is a relatively small trachelid genus, with 24 described species distributed in South and Southeast Asia (Li et al. 2022;WSC 2023).Among them, nine and one species have been recorded from China and Vietnam, respectively (Zhu et al. 1998;Zhao and Peng 2014;Jin et al. 2015;Liu et al. 2020;Li et al. 2022;Lin et al. 2023;WSC 2023).This genus is composed of four species groups: the dusun group, the fukasawana group, the kinabaluensis group, and the phyllicola group (Deeleman-Reinhold 2001; Liu et al. 2020).The kinabaluensis group includes 15 known species, making it the most species-rich group in the genus (Dankittipakul et al. 2011;Liu et al. 2020;Li et al. 2022;Lin et al. 2023).Members of this species group can often be found in forest leaf litter (Deeleman-Reinhold 2001;Liu et al. 2020).
In the present study, we describe three new species based on males and females from China and Vietnam which are assigned to the kinabaluensis group.

Materials and methods
Specimens were examined and measured with a Leica M205 C stereomicroscope.Left male palps and epigynes were photographed.Vulvae were treated in a warm 10% potassium hydroxide (KOH) solution to dissolve soft tissues before illustration.Images were captured with a Canon EOS 750D wide zoom digital camera (24.2 megapixels) mounted on the stereomicroscope mentioned above, and assembled using Helicon Focus v. 3.10.3image-stacking software (Khmelik et al. 2005).All measurements are given in millimetres (mm).Leg measurements are shown as: total length (femur, patella, tibia, metatarsus, tarsus).Leg segments were measured on their dorsal side.The species distribution map was generated with ArcGIS v. 10.2 (ESRI Inc.).Type specimens are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China and the Vietnam National Museum of Nature (VNMN) in Hanoi, Vietnam.
Diagnosis.The new species resembles U. fabaria Zhao &Peng, 2014 (cf. Figs 1-3 andJin et al. 2015: 573, figs 4-6), as males have a similar long RTA (Fig. 1B, C), and females have a nearly trapezoidal atrium (A) (Fig. 2A), bean-shaped bursae (B) (Fig. 2B), and laminar fertilization ducts (FD) (Fig. 2B).Males can be distinguished by the terminal portion of embolus slightly twist, almost reaching cymbium distally (Fig. 1B; vs terminal portion of embolus straight, subdistally reaching cymbium in U. fabaria), by the short subtegulum (ST), which does not reach the embolus (E) in ventral view (Fig. 1B; vs subtegulum long, almost reaching embolus in ventral view in U. fabaria), and by the sperm duct (SD) extending to the base of tegulum (Fig. 1B; vs sperm duct separated from the base of tegulum by nearly three times the width of the sperm duct in U. fabaria).Females can by distinguished by the copulatory openings (CO) transverse, separated by about three times their diameter (Fig. 2A; vs copulatory openings oblique, separated by less than their diameter in U. fabaria), by the copulatory ducts (CD) strongly convoluted, basal and middle part with two twists, distal part coiled around connecting duct (CnD) (Fig. 2B; vs copulatory ducts not twisted in U. fabaria), by the connecting ducts located on the area between copulatory openings (Fig. 2A, B; vs connecting ducts located on the lateral areas of copulatory openings in U. fabaria), by the posterior part of bursae wider than middle part of it (Fig. 2B; vs posterior part of bursae as wide as middle part of it in U. fabaria), and by the spermathecae (SP) separated by about half of their diameter (Fig. 2B; vs spermathecae separated by less than half of their diameter in U. fabaria).
Palp (Fig. 1A-C): tibia shorter than half of cymbium length; RTA about 1.08 times longer than tibia, with wide base and narrow, blunt tip, with slight curvature distally.Bulb nearly oval, posterior part wider than anterior part; tegulum approximately 1.46 times as long as its maximum width in ventral view; subtegulum (ST) sclerotized, occupying approximately 1/5 of tegulum width in ventral view; sperm duct (SD) distinct, U-shaped in ventral view, extending to base of tegulum.Embolus (E) long, anticlockwise, obliquely coiled twice, coils as wide as minimum width of tegulum; basal portion of embolus lamellar, wide, arising at 12:30 o'clock from bulb; terminal portion of embolus filiform, slightly twist, suspended in above distal cymbial alveolus.
Epigyne (Fig. 5A, B): epigynal plate longer than wide, spermathecae distinct and bursae indistinct in ventral view.Atrium (A) large and nearly trapezoidal, occupying about 2/3 of epigyne length, posterior margin wider than anterior margin.Copulatory openings (CO) semicircular, located at anteriorly, separated by about their diameter.Copulatory ducts (CD) long, anterior part wide and posterior part narrow; copulatory ducts convoluted posteriorly, forming irregular loops.Connecting ducts (CnD) thin and slender, located on lateral areas of copulatory openings, separated by more than spermathecae (SP) diameter.Bursae (B) nearly rod-shaped, anterior part strongly constricted and curved, posterior part three times width of anterior part; bursae with several small clusters of glandular particles (GP) on surface of distal margin.Spermathecae globular, separated by less than half of their diameter.Fertilization ducts (FD) laminar, separated from each other by posterior width of atrium.
Distribution.Vietnam (Vinh Phuc, type locality; Fig. 10).3A, B) by having similar long RTA, wide at the base, narrow at the end, and having a hook-shaped tip pointing anteriorly (Fig. 7B, C), but males of this species can be distinguished by the elliptical bulb, embolus (E) slightly shorter than widest part of bulb (Fig. 7B; vs bulb droplet-shaped, anterior part about half of posterior part, embolus about half of widest of bulb in U. fabaria; bulb almost square, embolus about as wide as widest of bulb in U. lata; bulb elliptical, embolus obviously shorter than widest of bulb in U. rama, U. subfabaria and U. linyejiei sp.nov.), by the subtegulum (ST) occupying approximately one-third of tegulum width, 3/5 of tegulum length in ventral view (Fig. 7B; vs 1/4 of tegulum width, 5/6 of tegulum length in U. fabaria; 1/4 of tegulum width, 4/5 of tegulum length in U. rama; 1/5 of tegulum width, 5/6 of tegulum length in U. subfabaria; 1/5 of tegulum width, 4/7 of tegulum length in U. linyejiei sp.nov.), and by the sperm duct (SD) extending to the base of tegulum (Fig. 7B; vs sperm duct separated from the base of tegulum by nearly three times the width of the sperm duct in U. fabaria and U. rama).Females resemble U. arcuata Zhao &Peng, 2014 (cf. Figs 8, 9C, D andZhao andPeng 2014: 579, figs 3, 4) in having similarly large copulatory openings (CO) (Fig. 8A) and an atrium (A) occupying about 5/6 of the length of the epigyne (Fig. 8A), but they can be distinguished by their approximately straight copulatory openings (Fig. 8A; vs copulatory openings strongly curved, arch-shaped in U. arcuata), by the copulatory ducts (CD) with two or three sharp twists (Fig. 8B; vs one or two twists in U. arcuata), by the bean-shaped bursae (B) (Fig. 8B; vs S-shaped bursae, anterior part strongly restricted and curved in U. arcuata), and by the spermathecae (SP), which are separated by about half of their diameter (Fig. 8B; vs spermathecae separated by less than half of their diameter in U. arcuata).
Palp (Fig. 7A-C): tibia shorter than half of cymbium length; RTA about 1.06 times longer than tibia, with wide base and narrow, blunt tip, straight section subdistally to distally, slightly curvature distally.Bulb elliptical, wider in middle part; tegulum approximately 1.34 times as long as its maximum width in ventral view; subtegulum (ST) sclerotized, occupying approximately 1/3 of tegulum width in ventral view; sperm duct (SD) distinct, U-shaped in ventral view, extending to the base of tegulum.Embolus (E) long, anticlockwise, obliquely coiled twice, coils as wide as tegulum; basal portion of embolus lamellar, wide, arising at 12:00-12:30 o'clock from bulb; terminal portion of embolus filiform, resting in distal cymbial alveolus.
Epigyne (Fig. 8A, B): epigynal plate longer than wide, spermathecae (SP) and bursae (B) distinct in ventral view.Atrium (A) large and nearly trapezoidal, occupying about 5/6 length of epigyne, posterior margin wider than anterior margin.Copulatory openings (CO) large, semicircular, located at anteriorly, separated by about their diameter.Copulatory ducts (CD) long, anterior part wide and posterior part narrow; copulatory ducts convoluted posteriorly, with two or three sharp twists.Connecting ducts (CnD) thinner than copulatory ducts, located on the lateral areas of copulatory openings, separated by more than spermathecae diameter.Bursae elliptical, separated by about 1.5 times their diameter; bursae with several small clusters of glandular particles (GP) on posterior surface, occupying about 1/5 of bursa diameter.Spermathecae globular, separated by less than their diameter.Fertilization ducts (FD) laminar, separated from each other by posterior width of atrium.

Figure 3 .
Figure 3. Utivarachna linyejiei sp.nov., holotype male (A, B) and paratype female (C, D) A-D habitus A dorsal view B ventral view C dorsal view D ventral view.Scale bars: 1.00 mm.

Figure 6 .
Figure 6.Utivarachna tamdao sp.nov., holotype male (A, B) and paratype female (C, D) A-D habitus A dorsal view B ventral view C dorsal view D ventral view.Scale bars: 1.00 mm.

Figure 9 .
Figure 9. Utivarachna zhengguoi sp.nov., holotype male (A, B) and paratype female (C, D) A-D habitus A dorsal view B ventral view C dorsal view D ventral view.Scale bars: 1.00 mm.