Sinamma danxia He, Zhu, Chen & Guo, 2024

He, Ailan, Zhu, Jinheng, Chen, Fang & Guo, Jing, 2024, The fourth species of Sinamma Lin & Li, 2014 (Araneae, Tetrablemmidae) from China, Biodiversity Data Journal 12, pp. e 134334-e 134334 : e134334-

Sinamma danxia He, Zhu, Chen & Guo sp. nov.

Materials

Type status: Holotype. Occurrence: recordedBy: Ailan He; Yingxiang Qiu; Jing Guo; Lijuan Gu; Xiaofei Zhong; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: 73DFDD29-0D7F-5D64-AD59-9D198D1970BC; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Sinamma ; Location: country: China; stateProvince: Guangdong; county: Renhua; verbatimLocality: Danxiashan National Nature Reserve (namely Danxia Mountain); verbatimElevation: 201 m; verbatimLatitude: 25.365556 ° N; verbatimLongitude: 113.739997 ° E; Event: samplingProtocol: Collected by hand picking and sieving leaf litter; year: 2022; month: 12; day: 8; Record Level: institutionCode: SGU-Tet 001

Type status: Paratype. Occurrence: recordedBy: Ailan He; Yingxiang Qiu; Jing Guo; Lijuan Gu; Xiaofei Zhong; individualCount: 18; sex: 5 males, 13 females; lifeStage: adult; occurrenceID: 107F52F4-C778-5F0C-A0BE-D8F319771CCC; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Sinamma ; Location: country: China; stateProvince: Guangdong; county: Renhua; verbatimLocality: Danxiashan National Nature Reserve (namely Danxia Mountain); verbatimElevation: 201 m; verbatimLatitude: 25.365556 ° N; verbatimLongitude: 113.739997 ° E; Event: samplingProtocol: Collected by hand picking and sieving leaf litter; year: 2022; month: 12; day: 8; Record Level: institutionCode: SGU-Tet 002-019

Description

Male (holotype). Colouration: body reddish-brown; legs yellowish-brown. Measurements: total length 1.61; carapace 0.75 long, 0.63 wide, 0.49 high; abdomen 1.01 long, 0.76 wide, 0.72 high; clypeus 0.36 high; sternum 0.42 long, 0.44 wide. Length of legs: I 1.90 (0.65, 0.22, 0.41, 0.29, 0.33); II 1.72 (0.54, 0.20, 0.39, 0.27, 0.32); III 1.52 (0.46, 0.18, 0.33, 0.27, 0.28); IV 2.01 (0.60, 0.17, 0.53, 0.37, 0.34). Leg formula: 4123.

Carapace (Fig. 1 A, C, Fig. 2 A and B): reticulated, margin with small denticles; ocular area distinctly raised (Fig. 2 A and B), with a pair of very small tubercles behind and almost same height as ocular area; clypeus very high, anterior margin rounded (Fig. 2 A); cheliceral horns long, basally wide, distally crooked, with tips parallel and pointing antereodorsally (Fig. 2 B); sternum with sparse setae, reticulate (Fig. 1 B). Legs: femur I swollen (Fig. 3 A); tibiae I – III with 3 trichobothria, respectively, tibia IV with 4 and metatarsi I-IV with one; tibia I with two large triangular subdistal tubercles, retrolateral one larger and prolateral one smaller (Fig. 3 B); metatarsus I constricted subdistally and with two small tubercles (Fig. 3 C).

Abdomen (Fig. 1 A – C): booklung covers oval, reddish-brown; dorsal scutum oval, finely reticulated; ventral scutum reticulated; postgenital plate smooth, narrow, slightly shorter in width to pre-anal plate; pre-anal plate slightly curved.

Palp (Fig. 3 D – F): femur smooth, slightly curved at mid-ventral side; patella approximately 1 / 2 of femur in length, connected to tibia sub-basally; bulb long, pyriform, with a distinct contraction in middle of ventral surface; embolus long, spiniform, strongly sclerotised and bending at a nearly right angle at base towards dorsally; sperm duct extending, visible through the bulbal integument.

Female (paratype). Colouration: same as in male. Measurements: total length 1.60; carapace 0.69 long, 0.57 wide, 0.37 high; abdomen 1.02 long, 0.81 wide, 0.76 high; clypeus 0.22 high; sternum 0.40 long, 0.41 wide. Length of legs: I 1.72 (0.55, 0.18, 0.40, 0.26, 0.33); II 1.61 (0.49, 0.18, 0.36, 0.26, 0.32); III 1.47 (0.43, 0.18, 0.31, 0.27, 0.28); IV 1.92 (0.58, 0.16, 0.50, 0.36, 0.32). Leg formula: 4123.

Carapace (Fig. 1 D, F, C and D): cephalic part raised, dorsal edge straight in lateral view (Fig. 2 D), ocular area not raised, clypeus lower than in male; cheliceral horn absent. Legs as in male, except for leg I not swollen.

Abdomen (Fig. 1 D – F): ventral episgastric scutum reticulated; postgenital plate straight, slightly shorter in width to pre-anal plate; pre-anal plate rectangular-shape; perigenital plate small, oval.

Genitalia (Fig. 4 A – C): epigynal fold wide, arched (Fig. 4 A and B); vulval stem wide, inverted triangular, strongly sclerotised; lateral horns slightly sclerotised, supporting the base of membranous vulval ducts that connect spermathecae; inner vulval plate triangle-shaped, rugose, slightly sclerotised; spermathecae translucent, oval, membranous (Fig. 4 C).

Diagnosis

Amongst the congeners, the new species can be easily distinguished from S. oxycera and S. quadrata by the presence of pointed cephalic tubercles in the latter two species (both sexes in S. oxycera and males in S. quadrata ). The new species is similar to S. yingae Tong & Li, 2022 in that both males and females lack pointed cephalic tubercles and in the pattern of leg tubercles on tibia and metatarsus I, but can be recognised by: Cheng et al. (2022); 1) dorsal surface of the cephalic part in females straight in lateral view (D) (vs. cephalic part slightly sloping ( Cheng et al. (2022): fig. 5 F )); 2) metatarsus I without proximal tubercle (Fig. 3 B and C) (vs. metatarsus I with one proximal tubercle ( Cheng et al. (2022): fig. 3 D )); 3) the length of the male palpal patella about 1 / 2 of the femur in length (Fig. 3 D and E) (vs. the patella about 2 / 3 femur in length ( Cheng et al. (2022): figs. 6 A and B )); 4) embolus bending at a nearly right angle at base (Fig. 3 D and E) (vs. the embolus slightly curved ( Cheng et al. (2022): figs. 6 A and B )); 5) vulval stem inverted triangular and inner vulval plate triangular with rugose surface (Fig. 4 C) (vs. vulval stem inverted trapezoidal and inner vulval plate finger-like with smooth surface ( Cheng et al. (2022): fig. 7 C )).

Etymology

The specific epithet refers to the type locality; noun in apposition.

Distribution

Known only from the type locality (Guangdong, China) (Fig. 5 )

Figures

Figure 1. Sinamma danxia sp. nov., holotype male (A – C), paratype female (D – F). A, D Habitus, dorsal view; B, E Habitus, ventral view; C, F Habitus, lateral view. Scale bars: 0.5 mm (A – F).

Figure 2. Sinamma danxia sp. nov., holotype male (A – B), paratype female (C – D). A, C. Prosoma, anterior views; B, D. Prosoma, lateral view. Scale bars: 0.2 mm (A – D). The arrows indicate small tubercles in the ocular area.

Figure 3. Sinamma danxia sp. nov., holotype male. A Left leg I, retrolateral view; B Left tibia I, dorsal view; C Left metatarsus I and tarsus I, dorsal view; D Left palp, prolateral view; E Same, retrolateral view; F Same, dorsal view. Abbreviations: dt = distal tubercles; ldt = large distal tubercles. Scale bars: 0.2 mm (A – F).

Figure 4. Sinamma danxia sp. nov., paratype female. A Genital area, ventral view; B Genital area, ventral view (cleared in pancreatin solution); C Endogyne, dorsal view. Abbreviations: EF = epigynal fold; IVP = inner vulval plate; LH = lateral horn; PA = pre-anal plate; PEG = perigenital plate; POG = postgenital plate; SR = seminal receptaculum; VD = vulval duct; VS = vulval stem. Scale bars: 0.2 mm (A – C).

Figure 5. Map showing the currently known localities of Sinamma spp.