Choiroblemma metok, Zhou & Zhang & Tong, 2024

Zhou, Yang, Zhang, Xiaoqing & Tong, Yanfeng, 2024, First record of the tetrablemmid armoured spiders (Araneae, Tetrablemmidae) from Xizang, China, with description of a new species, Biodiversity Data Journal 12, pp. e 143503-e 143503 : e143503-

Choiroblemma metok sp. nov.

Materials

Type status: Holotype. Occurrence: recordedBy: Panlong Wu; individualCount: 1; sex: male; lifeStage: adult; occurrenceID: DC568B4F-4B5F-5C52-B2B8-6E19CAB09EB5; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Choiroblemma ; specificEpithet: metok ; Location: country: China; stateProvince: Xizang; county: Nyingchi City, Metok County; verbatimCoordinates: 29°19′30″N, 95°19′59″E; Identification: identifiedBy: Yanfeng Tong; Event: eventDate: 21 September 2013; Record Level: institutionCode: SYNU- 1379

Type status: Paratype. Occurrence: recordedBy: Panlong Wu; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: C59EA94F-9374-5001-A7B0-3902049CDCE1; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Choiroblemma ; specificEpithet: metok ; Location: country: China; stateProvince: Xizang; county: Nyingchi City, Metok County; verbatimCoordinates: 29°19′30″N, 95°19′59″E; Identification: identifiedBy: Yanfeng Tong; Event: eventDate: 21 September 2013; Record Level: institutionCode: SYNU- 1380

Type status: Paratype. Occurrence: recordedBy: Zhizhong Gao; individualCount: 5; sex: 1 male, 4 females; lifeStage: adult; occurrenceID: 7572C843-6313-5D55-93A0-100E837D9D38; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Choiroblemma ; specificEpithet: metok ; Location: country: China; stateProvince: Xizang; county: Nyingchi City, Metok County; locality: hills behind the Petrochina Motuo gas station ; verbatimCoordinates: 29°19′46″N, 95°20′32″E; Identification: identifiedBy: Yanfeng Tong; Event: eventDate: 22 September 2013; Record Level: institutionID: SYNU- 1374-1378

Type status: Paratype. Occurrence: recordedBy: Yejie Lin; individualCount: 2; sex: male; lifeStage: adult; occurrenceID: C376BB62-898E-50BC-88A1-44B89FC39352; Taxon: order: Araneae ; family: Tetrablemmidae ; genus: Choiroblemma ; specificEpithet: metok ; Location: country: China; stateProvince: Xizang; county: Nyingchi City, Metok County; locality: Yadang Village ; verbatimCoordinates: 29°20′36″N, 95°20′48″E; Identification: identifiedBy: Yanfeng Tong; Event: eventDate: 6 August 2013; Record Level: institutionID: SYNU-F- 091-092

Description

Male (holotype). Colouration: body orange brown, legs yellowish. Habitus as in Fig. 1 A, C and E.

Measurements: total length 1.13; carapace 0.55 long, 0.47 wide, 0.29 high; abdomen 0.73 long, 0.52 wide, 0.47 high; clypeus 0.16 high; sternum 0.32 long, 0.35 wide. Length of legs: I 1.30 (0.42, 0.14, 0.32, 0.21, 0.21); II 1.16 (0.38, 0.14, 0.26, 0.19, 0.19); III 0.99 (0.28, 0.13, 0.22, 0.20, 0.16); IV 1.37 (0.42, 0.14, 0.36, 0.24, 0.21).

Carapace reticulated, margin with small denticles; cephalic region slightly sloped in lateral view; eyes in three distinct pairs; clypeus very high, with distinct snout-like protrusion (Fig. 1 B and F); chelicerae frontally with basally wide, conical horn, distally with well-developed prong (Fig. 3 E); sternum with sparse setae, reticulated (Fig. 1 D). Opisthosoma oval; dorsal scutum large, oval, glossy, densely pitted, covered with fine setae; pulmonary plate glossy, with pits for setae; pre-anal plate much wider than postgenital plate. Legs unmodified.

Palp (Fig. 3 A – D): femur and tibia slightly swollen; cymbium with a conical apophysis; bulb subglobular; the embolus very thin and needle-like, conductor sclerite short, nearly half length of the embolus.

Female (SYNU- 1380). As in male, except as noted. Habitus as in Fig. 2 A, C and E.

Measurements: total length 1.23; carapace 0.50 long, 0.47 wide, 0.27 high; abdomen 0.83 long, 0.65 wide, 0.48 high; clypeus 0.13 high; sternum 0.34 long, 0.36 wide. Length of legs: I 1.25 (0.41, 0.15, 0.29, 0.20, 0.20); II 1.12 (0.41, 0.14, 0.21, 0.18, 0.18); III 1.00 (0.30, 0.13, 0.22, 0.18, 0.17); IV 1.42 (0.45, 0.16, 0.35, 0.25, 0.21).

Cephalic region slightly elevated in lateral view; clypeus without the snout-like protuberance; chelicerae horn absent (Fig. 2 E and G).

Abdomen: epigynal fold wide; pre-anal plate with a rectangular extension on posterior margin (Fig. 2 H).

Genitalia: a very thin duct running into a small vestibule; vulval stem wide, strongly sclerotised; lateral horns long, slightly sclerotised, supporting the base of vulval ducts of seminal receptaculum (Fig. 3 H).

Diagnosis

This new species is similar to Choiroblemma bengalense and Choiroblemma rhinoxunum ( Bourne 1980: figs. 31–44) in the snout-like protrusion of clypeus of male and the thin embolus, but can be distinguished by the thin and short conductor (Fig. 3 A – C), vs. wide and robust, the conical apophysis of male palpal cymbium (Fig. 3 C and D) vs. lacking, the distally prong of male chelicerae (Fig. 3 E) vs. lacking and the extension of female pre-anal plate on posterior margin (Fig. 2 H) vs. on the middle area.

Etymology

The specific name is a noun in apposition taken from the type locality.

Distribution

Known only from the type locality (Fig. 4 ).

Figures

Figure 1. Choiroblemma metok sp. nov., male holotype. A habitus, dorsal view; B prosoma, dorsal view; C habitus, ventral view; D prosoma, ventral view; E habitus, lateral view; F prosoma, lateral view; G prosoma, anterior view; H abdomen, ventral view. Arrows show the snout-like protuberance in Figs. B and F. Scale bars: 0.4 mm.

Figure 2. Choiroblemma metok sp. nov., female paratype (SYNU- 1380). A habitus, dorsal view; B prosoma, dorsal view; C habitus, ventral view; D prosoma, ventral view; E habitus, lateral view; F prosoma, lateral view; G prosoma, anterior view; H genital area, ventral view, arrow shows the extension. Abbreviations: EF = epigynal fold; PA = pre-anal plate; POG = postgenital plate. Scale bars: 0.4 mm.

Figure 3. Choiroblemma metok sp. nov. A male left palp, prolateral view; B male left palp, distal view; C male left palp, retrolateral view; D left palpl tibia and cymbium, dorsal view; E male chelicerae, anterior view; F male chelicerae, lateral view; G female genital area, ventral view; H female genital area, dorsal view. Abbreviations: CA = conical apophysis; CH = cheliceral horn; CO = conductor; EM = embolus; LH = lateral horn; PR = prong; PA = pre-anal plate; POG = postgenital plate; SR = seminal receptaculum; VD = vulval duct; VE = vestibule; VS = vulval stem. Scale bars: 0.1 mm (A – F); 0.2 mm (G, H).

Figure 4. Distribution records of Choiroblemma species from China and India, green circles represent two known species, red circle indicates the new species. 1. Choiroblemma bengalense Bourne, 1980; 2. Choiroblemma metok sp. nov.; 3. Choiroblemma rhinoxunum Bourne, 1980.