Male (holotype). Total length 2.05 mm.

Carapace (Fig. 1A and B) 0.94 mm long, 0.72 mm wide, anteriorly narrowed to 0.6 × its maximum width, with abundant large pore-bearing depressions on lateral and posterior parts. Eye sizes and interdistances: AER and PER procurved in dorsal view; AME 0.04, ALE 0.06, PME 0.05, PLE 0.05, AME−AME 0.02, AME−ALE 0.02, PME−PME 0.06, PME−PLE 0.05, AME−PME 0.04, AME−PLE 0.12, ALE−ALE 0.14, PLE−PLE 0.24, ALE−PLE 0.06; MOA 0.13 long, front width 0.1, back width 0.16. Chelicerae with two promarginal (distal larger) and three retromarginal teeth (median largest). Endites longer than wide, with sparse pore-bearing depressions. Labium wider than long, anteriorly with three pairs of strong setae, subposteriorly with a constriction, posteriorly with a row of pore-bearing depressions. Sternum strongly sclerotised, longer than wide, covered with many pits, anteromedially with a wide notch, laterally with sclerotised and thickened margin, posterior end blunt. Legs (Fig. 1A and B). Measurements: I 2.2 (0.62, 0.20, 0.62, 0.48, 0.28); II 1.87 (0.55, 0.22, 0.43, 0.42, 0.25); III 1.71 (0.49, 0.21, 0.31, 0.43, 0.27); IV 2.10 (0.56, 0.22, 0.45, 0.55, 0.32); leg formula 1423; spination: tibiae I plv 6, rlv 6 II plv 6, rlv 6; metatarsi I plv 4, rlv 4, II plv 4, rlv 4; tarsi I plv 3, rlv 3, II plv 3, rlv 3. Pedicel (Fig. 1A and B) 0.21 mm long, cylindrical, sclerotised. Abdomen (Fig. 1A, B) 0.91 mm long, 0.79 mm wide, scutum covering entire dorsum; venter with sclerotised epigastric region and trapezoidal inframamillary scutum in front of spinnerets.

Figure 1.  

Orthobula jiangxi Liu, sp. n., male holotype and female paratype (A–D). A–B Male habitus, dorsal and ventral view; C–D Female habitus, dorsal and ventral view. Scale bars: 0.5 mm.

Colouration (Fig. 1A and B). Carapace reddish-brown, with brown spots around depressions. Each eye with distinct black eye cup. Chelicerae and endites yellow. Endites reddish. Labium reddish, posterior part reddish-brown. Sternum reddish, with dark mottled sub-margin and reddish-brown margin. Legs yellow, with dark brown stripes on prolateral side of femorae. Pedicel dark brown. Abdomen reddish-brown, with three branched dark brown stripes anteriorly and large semi-oval dark brown mark posteriorly; venter yellow, with reddish sclerotised epigastric plate anteriorly and scutum posteriorly.

Palp (Fig. 2). Palpal femur longer than patella + tibia, with small hook-shaped ventrodistal apophysis. Patella short, with small tubercle. Tibia slightly longer than patella, with finger-shaped retrodistal apophysis directed ventrally. Cymbium longer than femur + patella + tibia. Subtegulum lamellar, slightly sclerotised. Intercalary sclerite located between subtegulum and tegulum, lamellar. Tegulum swollen, slightly longer than wide, narrowing apically, with slight constriction in the middle part. Sperm duct narrow, n-shaped, with sharp turn in median part, nearly reaching the constriction. Embolus spine-like, short, reaching apex of cymbium.

Figure 2.  

Orthobula jiangxi Liu, sp. n., male palp of holotype (A–G). A–B, D Prolateral, prolater-ventral and retrolateral view; C detail of palpal femur, ventral view E–G ventral, retrolateral and dorso-retrolateral view. Abbreviations: Em = embolus; IS = intercalary sclerite; RTA = retrodistal tibial apophysis; St = subtegulum; Tu = tubercle; VFA = ventrodistal femoral apophysis. Scale bars: 0.1 mm.

Female (Fig. 1C and D and Fig. 3). As in male, except as noted. Total length 2.15 mm.

Figure 3.  

Orthobula jiangxi Liu, sp. n., female epigyne of paratype (A–B). A–B ventral and dorsal (B) view. Abbreviations: Bu = bursa; CD = copulatory duct; CO = copulatory opening; FD = fertilisation duct; S1= primary spermatheca; S2 = secondary spermatheca, SBB = sclerotised bursal base. Scale bars: 0.1 mm.

Carapace 1.03 mm long, 0.81 mm wide. Eye sizes and interdistances: AME 0.05, ALE 0.06, PME 0.07, PLE 0.07, AME−AME 0.01, AME−ALE 0.01, PME−PME 0.07, PME−PLE 0.02, AME−PME 0.04, AME−PLE 0.11, ALE−ALE 0.14, PLE−PLE 0.25, ALE−PLE 0.04. MOA 0.17 long, front width 0.12, back width 0.19. Pedicel 0.07 long. Abdomen (Fig. 1C and D) 0.98 long, 0.97 wide, without dorsal and ventral scutum. Leg measurements: I 2.26 (0.70, 0.24, 0.72, 0.57, 0.27); II 2.04 (0.61, 0.24, 0.45, 0.47, 0.27); III 1.98 (0.56, 0.22, 0.47, 0.43, 0.30); IV 2.62 (0.67, 0.25, 0.63, 0.71, 0.36).

Colouration as in Fig. 1C and D. Abdomen cream with black markings. The colour clearly differs from that of the male.

Epigyne (Fig. 3). Copulatory openings located at the posterior part of epigynal ridge, inclined, directed anteromedially. Copulatory ducts very short, shorter than width of sclerotised bursal base. Sclerotised bursal base round, separated by half their width. Bursae fan-shaped, very large, covering more than 2/3 of epigynal field. Sclerotised bursal base connected to oval secondary spermathecae by short ducts, longer than width of primary spermathecae. Secondary spermathecae connecting with oval primary spermathecae, closely touching each other, arranged in a line. Fertilisation ducts located at primary spermathecae, curved anteriorly.

The male of this new species is similar to that of Orthobula spiniformis Tso, Zhu, Zhang & Zhang, 2005 (Tso et al. 2005: 47, figs. 5 and 6) in having a spine-like and straight embolus, but can be distinguished from it by the hook-shaped ventrodistal femoral apophysis (vs. short and spine-like) and thin retrolateral tibial apophysis (vs. thick) (Fig. 2). The female of the new species resembles those of O. aethiopica Haddad, Jin & Platnick, 2022 (Haddad et al. 2022: 361, figs. 54 and 55), O. arca Haddad, Jin & Platnick, 2022 (Haddad et al. 2022: 364, figs. 59 and 60) and O. spiniformis (Tso et al. 2005: 47, figs. 5 and 6) in having round, slightly separated, sclerotised bursal base, but it can be easily distinguished by two pairs of spermathecae (vs. one) (Fig. 3).

The species name is derived from the name of the type locality; noun in apposition.

Known from Yichun, Ji’an and Ganzhou Cities in Jiangxi Province, China (Fig. 4). It seems that this species is more widespread within this Province.

Figure 4.  

Records of Orthobula jiangxi Liu, sp. n., from Jiangxi Province, China.

It was collected from leaf litter in areas of broad-leaved forests in hilly areas.

The genus Orthobula has a wide distribution, with a rich population in forest litter in tropical to subtropical regions. However, this group has not received much attention in China and, until now, only eight known species have been reported from this huge country (World Spider Catalog 2022). The main reasons include the following: firstly, most species of Orthobula are difficult to collect and observe due to their very small body size; secondly, many Orthobula species are difficult to distinguish from their closely-related species, especially in males; finally, the descriptions of the new species from China were superficial and only a few ink drawings were provided, resulting in some difficulties for later taxonomic works.