Liphistius desultor Schiödte, 1849 from Malaysia.

Liphistius can be distinguished from the other seven genera by having the male palps bearing tibial apophysis (TiA) (Figs 3A, 5C, 7C, 9A), clavate trichobothria on the dorsal side of cymbia and leg tarsi, and vulvae possessing median receptacular cluster (RC) and sclerotized poreplate (PPl) (Figs 4, 6, 8, 10).

China (Yunnan Province), Indonesia (Sumatra), Laos, Myanmar, Peninsular Malaysia, and Thailand.

Eleven named Liphistius species in Myanmar were grouped into three species-groups: the birmanicus-group, comprising nine valid species; the bristowei-group, consisting of one known species; and the trang-group, also containing one known species (Schwendinger 1990; Schwendinger et al. 2022; Sivayyapram et al. 2024). All named Liphistius species of the birmanicus-group were described based on both sexes, except for L. hpruso Aung, Xu, Lwin, Sang, Yu, Liu, Liu & Li, 2019, which is only known from females. In this study, four new Liphistius species belonging to the birmanicus-group are described, identified according to the morphology of their copulatory organs in both sexes.

L. birmanicus, L. cupreus Schwendinger & Huber, 2022, L. ferox Schwendinger & Huber, 2022, L. hpruso, L. lahu Schwendinger, 1998, L. lordae Platnick & Sedgwick, 1984, L. metopiae Schwendinger, 2022, L. nabang Yu, Zhang & Zhang, 2021, L. pinlaung Aung, Xu, Lwin, Sang, Yu, Liu, Liu & Li, 2019, L. platnicki Schwendinger & Huber, 2022, L. pyinoolwin Xu, Yu, Aung, Yu, Liu, Lwin, Sang & Li, 2021, L. tung Schwendinger, 2022.

Holotype : Myanmar ♂, Shan State, 16 km W of Kalaw Township; 20.70°N, 96.52°E, alt. 944 m; 27.07.2019; D. Li et al. leg.; XUX-2019-061A. Paratypes: 8♀♀, same data as for holotype; 27.07.2019 and 15.07.2018; XUX-2019-062/063/064/065/066/067A/068; XUX-2018-124.

The male of L. kalaw sp. nov. resembles those of L. birmanicus and L. pinlaung in having a distinct contrategular process (cp) (Fig. 3B, E), but it can be distinguished from L. birmanicus by the relatively wider base of the contrategular process (cp) (Fig. 3E vs fig. 13E in Schwendinger et al. 2022), and from L. pinlaung by the cumulus (Cu) which has shorter spines (Fig. 3A–C vs fig. 4C in Aung et al. 2019). The female of L. kalaw sp. nov. can be distinguished from that of L. hpruso by the relatively wider posterior stalk (PS) (Fig. 4C vs fig. 3B–E in Aung et al. 2019).

Figure 3. 

Male palp of Liphistius kalaw sp. nov. A, E prolateral view B ventral view C, F retrolateral view D dorsal view, red arrows show arched projection and triangular process of CT G distal view. Abbreviations: CT = contrategulum; cp = contrategular process; Cu = cumulus; E = embolus; PC = paracymbium; PeP = paraembolic plate; ST = subtegulum; T = tegulum; TiA = tibial apophysis. Scale bars: 0.5 mm.

Figure 4. 

Vulva of Liphistius kalaw sp. nov. A, C dorsal view B, D ventral view. Abbreviations: CDO = central dorsal opening; GA = genital atrium; PS = posterior stalk; PPl = poreplate; RC = receptacular cluster; a = length of poreplate transverse; b = width of poreplate. Scale bars: 0.5 mm.

Male holotype. Carapace yellowish brown, with few short, scattered bristles; opisthosoma yellowish brown, with 12 brown tergites, close to each other, 2–6^th larger than others, 5^th largest; chelicerae robust, promargin with 13 denticles of variable size; labium and sternum yellowish brown, with few short setae on anterior margin and many long setae on elongated posterior margin; legs yellowish brown, with strong setae and spines. Measurements: BL 13.65, CL 5.94, CW 6.07, OL 8.00, OW 5.36; eye sizes and interdistances: AME 0.08, ALE 0.54, PME 0.27, PLE 0.43, AME–AME 0.11, AME–ALE 0.15, PME–PME 0.08, PME–PLE 0.10, ALE–PLE 0.17, ALE–ALE 0.12, PLE–PLE 0.34, AME–PME 0.10; labium 1.06 long and 0.98 wide; sternum 3.08 long and 0.96 wide; legs: I 18.36 (4.81, 2.57, 3.87, 4.60, 2.51), II 20.24 (5.64, 2.56, 4.23, 5.07, 2.74), III 20.46 (5.64, 2.37, 4.42, 6.00, 3.03), IV 27.56 (6.97, 2.84, 5.57, 8.17, 4.01).

Palp: tibial apophysis (TiA) with 4 tapering setae of similar length (Fig. 3C); paracymbium (PC) with many setae situated on tip (Fig. 3A–C); cumulus (Cu) slightly elevated, with 8 tapering spines (Fig. 3A–C); subtegulum with weakly developed apophysis (Fig. 3B); contrategulum (CT) with arched projection distally, and large triangular process in prolateral view (Fig. 3A, B, D); tegulum (T) fan-shaped with serrated edge and longitudinal ridges (Fig. 3C, F); paraembolic plate (PeP) narrow, sclerotized (Fig. 3A, F); embolus (E) with 4 distinct longitudinal ridges reaching tip in retrolateral view, and with several denticles along longitudinal ridges (Fig. 3B–F).

Female paratype (XUX-2019-062). Carapace yellowish brown, with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, with gray patches, 2–6^th larger than others, 5^th largest; chelicerae robust, reddish brown; promargin of cheliceral groove with 12 denticles of variable size; labium yellowish brown, sternum with several setae; legs with strong setae and spines. Measurements: BL 11.56, CL 5.82, CW 5.22, OL 6.23, OW 4.62; eye sizes and interdistances: AME 0.07, ALE 0.56, PME 0.29, PLE 0.42, AME–AME 0.09, AME–ALE 0.15, PME–PME 0.06, PME–PLE 0.09, ALE–PLE 0.11, ALE–ALE 0.07, PLE–PLE 0.35, AME–PME 0.08; labium 3.00 long and 0.61 wide; sternum 1.19 long and 1.13 wide; palp 10.25 (3.62, 1.74, 2.36, 2.53), legs: I 12.78 (4.29, 2.03, 2.63, 2.37, 1.46), II 12.89 (4.17, 2.03, 2.56, 2.59, 1.54), III 13.42 (4.13, 1.84, 2.75, 2.78, 1.92), IV 19.33 (5.57, 2.32, 3.81, 4.91, 2.72).

Vulva: poreplate (PPl) slightly wider than long, with pair of large anterior lobes and pair of small anterolateral lobes; central dorsal opening (CDO) circular, racemose receptacular cluster (RC) slightly long; posterior stalk (PS) axe-shaped; lateral margins of genital atrium (GA) membranous (Fig. 4).

Females vary in body size. The range measurements of females (N = 8): BL 8.55–16.11, CL 4.48–7.20, CW 3.90–6.43, OL 4.18–8.56, OW 3.00–7.36. The number of denticles on the promargin of cheliceral groove varies from 11 to 14 (N = 8).

The species epithet “kalaw” refers to the type locality, Kalaw Township; it is treated as a noun in apposition.

Mandalay Region (Kalaw Township), Myanmar.

Holotype : Myanmar ♂, Chin State, Kanpetlet Township, Kanpetlet Matupi Rd; 21.19°N, 94.05°E, alt. 1469 m; 17.07.2019; D. Li et al. leg.; XUX-2019-026. Paratypes: 5♀♀, same locality as for holotype; 17–18.07.2019; XUX-2019-020/021/024/031/033.

The male of L. kanpetlet sp. nov. can be distinguished from those of L. birmanicus by having the paracymbium (PC) bearing a distal process (Fig. 5C vs lacking a distal process, fig. 13H in Schwendinger et al. 2022), and from L. kalaw sp. nov. by the contrategulum (CT) which has a blunt process (Fig. 5D vs slightly sharp process, Fig. 3E). The female of L. kanpetlet sp. nov. differs from that of L. hpruso by having two relatively larger anterior lobes (Fig. 6 vs fig. 3B–E in Aung et al. 2019).

Figure 5. 

Male palp of Liphistius kanpetlet sp. nov. A, E prolateral view B ventral view; C, F retrolateral view, red arrow shows distal process of PC D dorsal view, red arrows show arched projection and triangular process of CT G distal view. Abbreviations: CT = contrategulum; cp = contrategular process; Cu = cumulus; E = embolus; PC = paracymbium; PeP = paraembolic plate; ST = subtegulum; T = tegulum; TiA = tibial apophysis. Scale bars: 0.5 mm.

Figure 6. 

Vulva of Liphistius kanpetlet sp. nov. A–C dorsal view D–F ventral view. Abbreviations: CDO = central dorsal opening; GA = genital atrium; PS = posterior stalk; PPl = poreplate; RC = receptacular cluster. Scale bars: 0.5 mm.

Male holotype. Carapace yellowish brown with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, 2–6^th larger than others, 4^th largest; chelicerae robust, promargin of cheliceral groove with 13 denticles of variable size; labium yellow, sternum yellow, with few short setae on anterior tip and many long setae on elongated posterior tip; legs reddish brown, with strong setae and spines; 8 spinnerets. Measurements: BL 12.41, CL 6.01, CW 6.06, OL 6.30, OW 4.19; eye sizes and interdistances: AME 0.06, ALE 0.56, PME 0.32, PLE 0.42, AME–AME 0.06, AME–ALE 0.16, PME–PME 0.10, PME–PLE 0.11, ALE–PLE 0.14, ALE–ALE 0.14, PLE–PLE 0.34, AME–PME 0.08; labium 0.96 long and 0.50 wide; sternum 2.63 long and 1.00 wide; legs: I 17.51 (4.82, 2.52, 3.79, 4.14, 2.24), II 18.36 (5.20, 2.19, 3.95, 4.72, 2.3), III 20.63 (5.46, 2.20, 4.41, 5.86, 2.70), IV 26.62 (7.18, 2.64, 5.40, 7.71, 3.69).

Palp: tibial apophysis (TiA) with 5 setae of different lengths (Fig. 5A–C); paracymbium (PC) with some setae situated on tip, and with pointed lateral process (Fig. 5C); and several tapering spines on slightly elevated cumulus (Cu) (Fig. 5B); subtegular apophysis weakly developed (Fig. 5B, F); contrategulum (CT) with arched projection distally, and wide triangular process in prolateral view (Fig. 5D); fan-shaped tegulum (T) with 6 longitudinal ridges (Fig. 5C); paraembolic plate (PeP) widely rounded, short, with curved margin in ventral view (Fig. 5A, F); embolus (E) sclerotized basally, with several denticles along longitudinal ridges reaching tip (Fig. 5C–G).

Female paratype (XUX-2019-024). Carapace brown with few short, scattered bristles; opisthosoma gray, with 12 brown tergites, close to each other, with gray patches, 2–6^th larger than others, 5^th largest; chelicerae robust, reddish brown; promargin of cheliceral groove with 10 denticles of variable size; labium yellow, sternum yellow with several setae; legs with strong setae and spines, without distinct annulations. Measurements: BL 11.71, CL 5.26, CW 5.15, OL 6.36, OW 4.70; eye sizes and interdistances: AME 0.09, ALE 0.50, PME 0.34, PLE 0.40, AME–AME 0.06, AME–ALE 0.19, PME–PME 0.07, PME–PLE 0.10, ALE–PLE 0.09, ALE–ALE 0.14, PLE–PLE 0.35, AME–PME 0.06; Labium 1.38 long and 0.59 wide; sternum 2.31 long and 1.19 wide; palp 8.05 (2.76, 1.36, 2.15, 1.78), leg I 10.24 (3.21, 1.60, 2.30, 2.01, 1.12), II 10.82 (3.43, 1.68, 2.27, 2.14, 1.30), III 11.14 (3.49, 1.51, 2.16, 2.51, 1.47), IV 15.54 (4.45, 1.94, 3.13, 3.71, 2.31).

Vulva: approximately rectangular poreplate (PPl) wider than long with smoothly curved posterior margin; with pair of large anterior lobes and pair of small anterolateral lobes, 2 anterior lobes separated from each other, but close to anterolateral lobes; central dorsal opening (CDO) small, situated in center of poreplate (PPl); racemose receptacular cluster (RC) long and narrow; posterior stalk (PS) axe-shaped; genital atrium (GA) with slightly sclerotized lateral margins (Fig. 6).

Females vary in body size. The range of measurements of females (N = 5): BL 9.70–14.85, CL 4.86–6.55, CW 4.20–8.63, OL 3.82–8.63, OW 3.82–7.09. The number of denticles on the promargin of cheliceral groove varies from 10–13 (N = 5).

The species epithet “kanpetlet” refers to the type locality, Kanpetlet Township; it is treated as a noun in apposition.

Chin State (Kanpetlet Township), Myanmar.

Holotype : Myanmar ♂, Shan State, Kyaukme Dist., Nawnghkio Township, Nawng Au Vill.; 22.26°N, 96.83°E, alt. 1096 m; 26.07.2019; D. Li et al. leg.; XUX-2019-054A. Paratypes: 9♂♂ 3♀♀, same data as for holotype; XUX-2019-054/054A/055/055A/055B/055D/056/056A/057/058/059/060; 5♂♂ 2♀♀, same township as for holotype; 22.30°N, 96.73°E, alt. 845 m; 26.07.2019 and 14.07.2018; XUX-2019-049/051/052/053, XUX-2018-116/119/123.

The male of L. nawngau sp. nov. resembles those of L. lordae and L. pyinoolwin in having an adpressed proximal tegular margin (Fig. 7C, F), but it can be distinguished from them by the tegulum (T), which bears a distinct transversal ridge in retrolateral view (Fig. 7C, F vs lacking transversal ridge, figs 5, 6 in Schwendinger 1990; fig. 4F in Xu et al. 2021), and by the embolus (E), which has smooth longitudinal ridges reaching tip (Fig. 7E vs having several denticles along longitudinal ridges, fig. 4F in Xu et al. 2021). The female of L. nawngau sp. nov. can be distinguished from that of L. hpruso by having the posterior stalk triangular (PS) (Fig. 8 vs nearly oval, fig. 3B–E in Aung et al. 2019).

Figure 7. 

Male palp of Liphistius nawngau sp. nov. A, E prolateral view B ventral view C, F retrolateral view D dorsal view, red arrows show arched projection and triangular process of CT G distal view. Abbreviations: CT = contrategulum; cp = contrategular process; Cu = cumulus; E = embolus; PC = paracymbium; PeP = paraembolic plate; ST = subtegulum; T = tegulum; TiA = tibial apophysis. Scale bars: 0.5 mm.

Figure 8. 

Vulva of Liphistius nawngau sp. nov. A, C dorsal view B, D ventral view. Abbreviations: CDO = central dorsal opening; GA = genital atrium; PS = posterior stalk; PPl = poreplate; RC = receptacular cluster. Scale bars: 0.5 mm.

Male holotype. Carapace brown with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, 2–6^th larger than others, 5^th largest; chelicerae robust, promargin of cheliceral groove with 11 denticles of variable size; labium and sternum yellowish brown, sternum with few short setae on anterior tip and many long setae on elongated posterior tip; legs yellowish brown, with strong setae and spines. Measurements: BL 15.47, CL 6.63, CW 6.57, OL 7.73, OW 5.56; eye sizes and interdistances: AME 0.08, ALE 0.72, PME 0.35, PLE 0.49, AME–AME 0.08, AME–ALE 0.20, PME–PME 0.08, PME–PLE 0.07, ALE–PLE 0.81, ALE–ALE 0.11, PLE–PLE 0.16, AME–PME 0.12; labium 0.81 long and 0.58 wide; sternum 2.59 long and 1.01 wide; legs: I 19.58 (5.67, 2.78, 4.03, 4.68, 2.42), II 20.42 (5.66, 2.78, 4.13, 4.96, 2.89), III 22.62 (5.96, 2.63, 4.54, 6.29, 3.20), IV 28.26 (7.16, 2.75, 5.82, 8.55, 3.98).

Palp: tibial apophysis (TiA) with four setae of similar length (Fig. 7A–C); paracymbium (PC) with several setae situated on tip (Fig. 7A–C); cumulus (Cu) slightly elevated, with 8 tapering spines (Fig. 7A–C); subtegulum (ST) with weakly developed apophysis (Fig. 7B, F); contrategulum (CT) with an arched projection distally, and triangular process with wide base (Fig. 7D); tegulum (T) with distinct transversal ridge in retrolateral view (Fig. 7C, F); paraembolic plate (PeP) narrow, sclerotized (Fig. 7A, F); embolus (E) with several longitudinal ridges reaching tip (Fig. 7E, F).

Female paratype (XUX-2019-053). Carapace yellowish brown with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, with gray patches, 2–6^th larger than others, 5^th largest; chelicerae robust, reddish brown; promargin of cheliceral groove with 12 denticles of variable size; labium and sternum yellowish brown; legs with strong setae and spines. Measurements: BL 14.24, CL 6.10, CW 5.30, OL 7.12, OW 4.96; eye sizes and interdistances: AME 0.08, ALE 0.57, PME 0.31, PLE 0.45, AME–AME 0.10, AME–ALE 0.17, PME–PME 0.09, PME–PLE 0.08, ALE–PLE 0.09, ALE–ALE 0.10, PLE–PLE 0.46, AME–PME 0.06; labium 1.23 long and 0.77 wide; sternum 2.68 long and 1.13 wide; palp 10.42 (3.63, 1.84, 2.77, 2.18), leg I 13.33 (4.16, 2.15, 2.90, 2.58, 1.54), II 16.85 (4.35, 2.26, 2.84, 2.84, 1.72), III 15.04 (4.37, 2.35, 2.90, 3.31, 2.11), IV 20.39 (5.92, 1.92, 4.48, 5.33, 2.74).

Vulva: poreplate (PPl) with pair of large anterior lobes and pair of relatively small anterolateral lobes; central dorsal opening (CDO) located at center of poreplate (PPl); receptacular cluster (RC) racemose, protrudes upper edge of poreplate (PPl); posterior margin of triangular posterior stalk (PS) almost straight; lateral margins of genital atrium (GA) slightly sclerotized (Fig. 8).

Males (N = 14): BL 12.64–16.98, CL 6.27–7.56, CW 6.02–7.56, OL 6.95–8.50, OW 4.60–6.40; females (N = 5): BL 10.55–14.24, CL 5.26–6.37, CW 4.47–5.63, OL 5.24–7.12, OW 4.33–4.96. The number of denticles on the promargin of male cheliceral groove varies from 10 to 13 (N = 12); in females, the number of denticles on the promargin of cheliceral groove varies from 11 to 12 (N = 5). The number of setae on tibial apophysis varies from 4 to 6.

The species epithet “nawngau” refers to the type locality, Nawng Au Village; it is treated as a noun in apposition.

Shan State, (Kyaukme District), Myanmar.

Holotype : Myanmar ♂, Mandalay Region, War Phyu Taung Vill.; 22.88°N, 96.12°E, alt. 553 m; 25.07.2019; D. Li et al. leg.; XUX-2019-038. Paratypes: 2♂♂ 3♀♀, same data as for holotype; XUX-2019-034–037/041.

The male of L. rostratus sp. nov. resembles those of L. cupreus, L. nabang, and L. platnicki in having distinctly elevated cumulus (Cu) (Fig. 9C), but it can be distinguished from them by the relatively larger paraembolic plate (PeP) (Fig. 9A, E vs figs 21A, 23K in Schwendinger et al. 2022; fig. 3A in Yu et al. 2021), and an indistinct contrategular process (cp) (Fig. 9B vs relatively large contrategular process, figs 21E, 23E in Schwendinger et al. 2022; fig. 3B in Yu et al. 2021). The female of L. rostratus sp. nov. resembles to that of L. cupreus in having vesicle clusters along the anterior margin of the poreplate (PPl), but it can be distinguished by the relatively longer posterior stalk (PS), with a length/width ratio 0.4–0.6 (Fig. 10 vs length/width ratio about 0.2–0.4, fig. 22 in Schwendinger et al. 2022).

Figure 9. 

Male palp of Liphistius rostratus sp. nov. A, E prolateral view B ventral view C, F retrolateral view D dorsal view G distal view, red arrow shows beak-like contrategular projection. Abbreviations: CT = contrategulum; cp = contrategular process; Cu = cumulus; E = embolus; PC = paracymbium; PeP = paraembolic plate; ST = subtegulum; T = tegulum; TiA = tibial apophysis. Scale bars: 0.5 mm.

Figure 10. 

Vulva of Liphistius rostratus sp. nov. A, C dorsal view B, D ventral view. Abbreviations: CDO = central dorsal opening; GA = genital atrium; PS = posterior stalk; PPl = poreplate; RC = receptacular cluster. Scale bars: 0.5 mm.

Male holotype. Carapace yellowish brown, with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, 2–6^th larger than others, 4^th largest; chelicerae robust, promargin of cheliceral groove with 12 denticles of variable size; labium and sternum yellowish brown, sternum with few short setae on anterior tip and many long setae on elongated posterior tip; legs yellowish brown, with strong setae and spines. Measurements: BL 9.34, CL 4.57, CW 4.26, OL 5.02, OW 3.59; eye sizes and interdistances: AME reduced, ALE 0.40, PME reduced, PLE 0.24, ALE–PLE 0.07, ALE–ALE 0.05, PLE–PLE 0.30; labium 0.98 long and 0.48 wide; sternum 2.09 long and 0.83 wide; legs: I 12.63 (3.80, 1.32, 2.60, 3.07, 1.84), II 13.19 (3.80, 1.32, 2.60, 3.07, 1.84), III 14.35 (3.79, 1.58, 3.33, 3.44, 2.21), IV 19.76 (4.76, 1.66, 4.13, 6.01, 3.20).

Palp: tibial apophysis (TiA) with 4 setae of similar length (Fig. 9A–C); paracymbium (PC) with several setae situated on tip (Fig. 9B, C); cumulus (Cu) distinct elevated with 5 tapering spines (Fig. 9C); subtegulum (ST) without apophysis (Fig. 9F); contrategulum (CT) with beak-like projection distally in distal view and small process in ventral view (Fig. 9B, G); tegulum (T) semicircular with flat surface and serrated edges, and proximal tegular margin with an elevated transverse ridge (Fig. 9B, C, F); paraembolic plate (PeP) sclerotized, narrow (Fig. 9A, E); embolus (E) with 3 distinct longitudinal ridges reaching tip retrolaterally, and several denticles along these longitudinal ridges (Fig. 9B, F).

Female paratype (XUX-2019-034). Carapace brown with few short, scattered bristles; opisthosoma brown, with 12 brown tergites, close to each other, 2–6^th larger than others, 5^th largest; chelicerae robust, reddish brown; promargin of cheliceral groove with 12 denticles of variable size; labium yellowish brown, sternum yellowish brown with several setae; legs with strong setae and spines. Measurements: BL 10.54, CL 4.5, CW 3.93, OL 6.47, OW 4.74; eye sizes and interdistances: AME 0.05, ALE 0.37, PME 0.19, PLE 0.29, AME–AME 0.07, AME–ALE 0.12, PME–PME 0.06, PME–PLE 0.06, ALE–PLE 0.09, ALE–ALE 0.10, PLE–PLE 0.32, AME–PME 0.08; labium 0.95 long and 0.38 wide; sternum 2.41 long and 0.99 wide; palp 7.10 (2.44, 0.98, 1.86, 1.82), leg I 8.89 (2.94, 1.34, 2.00, 1.62, 0.99), II 9.69 (3.40, 1.09, 2.02, 1.98, 1.20), III 9.48 (2.29, 1.05, 2.59, 2.38, 1.17), IV 13.71 (3.21, 1.44, 3.11, 3.80, 2.21).

Vulva: about rectangular poreplate (PPl) with pair of anterior lobes; central dorsal opening (CDO) located below center of poreplate (PPl); racemose receptacular cluster (RC) small; posterior stalk (PS) as wide as poreplate (PPl), lateral margins of genital atrium (GA) slightly sclerotized (Fig. 10).

Males (N = 3): BL 9.34–10.31, CL 4.57–5.24, CW 4.26–5.83, OL 4.73–5.10, OW 3.40–3.40; females (N = 4): BL 10.54–12.35, CL 4.50–6.31, CW 3.93–5.47, OL 6.47–6.87, OW 4.64–4.79. The number of denticles on the cheliceral promargin varies from 12 to13 (N = 6). In addition, the male lacking an AME and PME, which may be degenerate during molting, is chosen as the holotype, because all paratype male palps are deformed.

The species name is derived from the Latin word “rostratus”, referring to the beak-like contrategulum of the male palp in distal view.

Mandalay Region (War Hpyu Taung), Myanmar.