Two new species of the genus Chilobrachys (Araneae, Theraphosidae) from China.

Two new species of the genus Chilobrachys Karsh, 1892 are described from China: Chilobrachysdominus Lin & Li, sp. nov. from Yunnan and C.jinchengi Lin & Li, sp. nov. from Tibet. Photos and a morphological description of the new species are given. The type specimens of the new species are deposited in the Institute of Zoology, Chinese Academy (IZCAS) in Beijing. Yejie Lin, Xunyou Yan, Shuqiang Li.

Introduction

The family Thorell, 1869 is one of the largest spider families in the world, including 1031 species in 153 genera (WSC 2021). This family is divided into 12 subfamilies (Foley et al. 2019), of which Simon 1889 and Pocock 1895 are known from Asia.

includes 125 species and subspecies in 12 genera. It can be distinguished from other subfamilies by the maxilla with an oval stridulatory organ on the prolateral surface, originating medially (not ventrally from the oral fringe), the maxilla with opposing modified setae in multiple rows on the retrolateral cheliceral surface, the posterior sternal sigillae distant from the sternal margins, the more than 60 labial cuspules, and the leg spines only found distally on the metatarsi; mature males lack a tibial apophysis on leg I (Nunn et al. 2016). In the genus Karsh, 1892, the anterior eyes are nearly in a straight line, the stridulating organ consists of short spines on the chelicerae and a single or double row of paddle hairs overlapped by a fringe of hairs on the maxillae, and the palpal organ of the male ending in a long and slender embolus (Raven 1985; Zhu and Zhang 2008).

Four species were hitherto known from China (Fig. 8, Li 2020; Li et al. 2021; Yao et al. 2021): (Yin & Tan, 2000) (Guangxi, Hainan), Song & Zhao, 1988 (Hubei, Chongqing), Zhu & Zhang, 2008 (Guizhou, Guangxi) and Yu et al., 2021 (Yunnan). Here, we describe two new species: sp. nov. from Xishuangbanna, Yunnan and sp. nov. from Medog, Tibet.

Figure 8.

Distribution records of species in China 1 sp. nov. 2 sp. nov. 3 (Yin & Tan, 2000) 4 Song & Zhao, 1988 5 Zhu & Zhang, 2008 6 Yu et al., 2021.

Materials and methods

All specimens are preserved in 75% ethanol and deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing (). Spermathecae were cleared in a trypsin enzyme solution to dissolve non-chitinous tissues. Specimens were examined under a LEICA M205C stereomicroscope. Photomicroscope images were taken with an Olympus C7070 zoom digital camera (7.1 megapixels). Photographs were stacked with Helicon Focus 6.7.1 and processed in Adobe Photoshop CC 2018.

The terminology used in the text and figures follows Bertani (2000). All measurements are in millimetres. Eye sizes were measured as the maximum diameter in either a dorsal or frontal view. Leg measurements are given as follows: total length (femur, patella, tibia, metatarsus, tarsus).

Abbreviations

A apical keel;

anterior lateral eyes;

anterior median eyes;

median ocular area;

prolateral inferior keel;

posterior lateral eyes;

posterior median eyes;

prolateral superior keel.

Taxonomy

Family

Subfamily Simon, 1889

Karsh, 1892

2C5BA966-A125-5ED0-A086-259D174C0332

Type species.

Karsch, 1892.

Diagnosis.

See Raven (1985) and Zhu and Zhang (2008).

Lin & Li sp. nov.

554A502C-BC8A-580F-9EE1-1CDE32F5A2FF

http://zoobank.org/36EC608E-6671-407E-9E1D-10C5497BADC0

Figs 1A , 2A–H , 3A, B , 4A–C , 8

Figure 1.

spp. nov., live males A sp. nov. B sp. nov. Photos by Qianle Lu, Zhengzhong Huang.

Figure 2.

sp. nov., holotype male A male habitus, dorsal B ocular tubercle C right palp maxillae D sternum E stridulatory lyra, lateral view F same, ventral view G chelicerae, retrolateral view H same, prolateral view.

Figure 3.

sp. nov., holotype, right palp bulb, rotated horizontally A retrolateral view B prolateral view.

Figure 4.

sp. nov., holotype, left palp A prolateral view B ventral view C retrolateral view.

Type material.

♂ (IZCAS-Ar42676), China: : Jinghong, Mount Jinuo, Jinuo Road, , elevation 1040 m, 16.XI.2021, Yi Ming leg.

The male of sp. nov. is similar to that of (Thorell, 1897) in having a long, strongly curved embolus, but can be distinguished by the embolus bent in at two thirds (vs. halfway in ).

Description.

Male (holotype, IZCAS-Ar42676) (Figs 2B–H, 3, 4). Carapace 13.27 long, 11.89 wide, black, with long purple setae. Opisthosoma black, with long black setae. Eye group 2.08 long, 1.04 wide (Fig. 2F). MOA 0.81 long, anterior width 1.05, posterior width 1.53. Eye sizes and interdistances: ALE 0.52, AME 0.44, PLE 0.37, PME 0.37; ALE–AME 0.17, AME–AME 0.24, PLE–PME 0.02, PME–PME 0.90. Fovea slightly procurved. Chelicerae black, with row of 14 promarginal teeth. Labium wider than long, with 368 cuspules. Sternum yellow brown with 3 pairs of sigilla. Legs with long and short setae. Tarsi I–III with 2 claws, tarsus IV with 3 claws, denticle number: I 4, II 6, III 5, IV 4. Leg measurements: I 43.77 (12.70 + 5.62 + 11.52 + 7.39 + 6.54), II 38.16 (10.54 + 4.88 + 9.92 + 7.63 + 5.19), III 35.95 (9.59 + 4.08 + 7.87 + 8.61 + 5.80), IV 48.11 (12.72 + 4.89 + 11.10 + 12.75 + 6.65). Leg formula: 4123.

Male palpal bulb (Fig. 3A, B; male palp with bulb Fig. 4A–C). Maxillae with lyra setae ventrally. Bulb oval, embolus slender and long, strongly curved at 90°, with A.

Female. unknown.

Etymology.

The species is named after the Latin word dominus, as this is one of the rarest spiders from China; noun (name) in apposition.

Distribution.

Known only from the type locality.

Lin & Li sp. nov.

FC2BA48D-1D5A-5726-9A67-44DCFCA49589

http://zoobank.org/CA76A9EC-61AF-4EBA-92F5-521EF797E229

Figs 1B , 5A–H , 6A, B , 7A–C , 8

Figure 5.

sp. nov., holotype (B–H) and paratype (A) males A male habitus, dorsal B ocular tubercle C right palp maxillae D sternum E stridulatory lyra, lateral view F same, ventral view G chelicerae, retrolateral view H same, prolateral view.

Figure 6.

sp. nov., holotype, right palp bulb, rotated horizontally A retrolateral view B prolateral view.

Figure 7.

sp. nov., holotype, left palp A prolateral view B ventral view C retrolateral view.

♂ (IZCAS-Ar42677), China: : Nyingchi, Medog, from Baibung to Muge, , elevation 1310 m, 21.VIII.2018, Jincheng Liu leg. 1♂ (IZCAS-Ar42678), same data as holotype.

The male of sp. nov. is similar to that (Pocock 1895), but can be distinguished by the length ratio of the embolus to the bulb, which is almost 2:1 in sp. nov. and is 1:1 in .

Male (holotype, IZCAS-Ar42677) (Figs 5B–H, 6, 7). Carapace 13.12 long, 10.21 wide, brown with long setae. Opisthosoma absent. Eye group 2.32 long, 0.97 wide (Fig. 5F). MOA 0.77 long, anterior width 0.89, posterior width 1.38. Eye sizes and interdistances: ALE 0.51, AME 0.45, PLE 0.42, PME 0.38; ALE–AME 0.34, AME–AME 0.25, PLE–PME 0.12, PME–PME 0.87. Fovea slightly procurved. Chelicerae dark brown, with row of 12 promarginal teeth. Labium wider than long, with 367 cuspules. Sternum yellow-brown, with 3 pairs of sigilla. Legs with long and short setae. Tarsi I–III with 2 claws, tarsus IV with 3 claws, denticle number: I 9, II 9, III 9, IV 12. Leg measurements: I 49.58 (14.23 + 7.12 + 11.21 + 9.89 + 7.13), II 45.77 (13.02 + 6.73 + 9.52 + 9.59 + 6.91), III 43.21 (11.51 + 5.48 + 8.24 + 11.51 + 6.47), IV 53.97 (14.32 + 5.87 + 11.22 + 15.96 + 6.60). Leg formula: 4123.

Male palpal bulb (Fig. 6A, B; male palp with bulb Fig. 7A–C). Maxillae with lyra setae ventrally. Bulb oval, embolus bow-shaped, strongly curved at 180°, with A, PI and PS. Distal edge of embolus relatively flat.

Female. unknown.

The species is named after Mr. Jincheng Liu, who collected the type material; noun (name) in the genitive case.

Known only from the type locality.