Mekonglema chiangmai Zhao & Li, 2022

Lin, Yejie, Zhao, Huifeng, Koh, Joseph K H & Li, Shuqiang, 2022, Taxonomy notes on twenty-eight spider species (Arachnida: Araneae) from Asia, Zoological Systematics 47 (3), pp. 198-270 : 240-245

Mekonglema chiangmai Zhao & Li , sp. nov. ( Figs 40–41 )

Diagnosis. This species resembles M. kaorao Zhao & Li, 2020 by having the tip of the embolus directed dorsally, but can be distinguished by the following characters which are distinct for a subtroglophile: six eyes encircled by black, blue or dark brown carapace (vs. typical characters of troglobiont, such as vestigial eyes, light yellow or pale carapace or abdomen); the ratio of the length of embolus/bulb less than 0.50 (vs. larger than 0.90); the spermathecae with tiny tubes (vs. one large tube only).

Description. Male (holotype, Fig. 40A ). Total length 0.97. Carapace 0.41 long, 0.34 wide. Abdomen 0.56 long, 0.50 wide. Carapace dark brown with sparse black dots. Six eyes encircled by black, clypeus height 0.07. Chelicerae, legs, labium, and endites light brown. Leg measurements: I 2.09 (0.59, 0.12, 0.60, 0.40, 0.38), II 1.93 (0.62, 0.12, 0.52, 0.34, 0.33), III 1.31 (0.44, 0.12, 0.36, 0.24, 0.16), IV 1.87 (0.60, 0.12, 0.52, 0.32, 0.32). Pair of distinct lateral scutae. Abdomen dark blue.

Palp ( Figs 40B–D ). Tibia 2.25 times longer than patella, cymbium 1.67 times longer than tibia, cymbial apophysis 1.5 times longer than width of cymbial base. Tibia and cymbium brown with black dots. Bulb nearly globular, embolus directed towards to cymbium, ratio of embolus/bulb length ca. 0.49.

Female (IZCAS-Ar43302, Figs 40A – B ). Total length 1.09. Carapace 0.38 long, 0.38 wide. Abdomen 0.71 long, 0.63 wide. Six eyes distinct and ringed with black, clypeus height 0.08. Coloration darker than male. Leg measurements: I 1.99 (0.63, 0.09, 0.59, 0.34, 0.34), II 1.65 (0.50, 0.09, 0.44, 0.31, 0.31), III 1.24 (0.34, 0.09, 0.31, 0.25, 0.25), IV 1.80 (0.56, 0.09, 0.50, 0.34, 0.31). Abdomen dark brown.

Genitalia ( Fig. 40C ). Insemination entrance membranous; spermatheca ellipsoid with membranous, tiny tubes.

Material examined. Holotype ♂ (IZCAS-Ar43298), Thailand: Chiang Mai, Chai Prakarn County, Ngam Cave (19.6557°N, 99.1006°E, elev. 644 m), 23 November 2016, S. Li et al., leg. Paratypes. 1♂ 3♀ (IZCAS-Ar43299–Ar43302), same data as holotype .

Distribution. Known only from the type locality.

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

Figures

Figure 40. Mekonglema chiangmai Zhao & Li, sp. nov., holotype male. A. Habitus, dorsal view; B. Embolus, apical view; C. Palp, prolateral view; D. Palp, retrolateral view. Abbreviations: E—embolus. Scale bars: A=0.2 mm; B=0.05mm; C–D=0.1mm.

Figure 41. Mekonglema chiangmai Zhao & Li, sp. nov., paratype female. A. Habitus, dorsal view; B. Habitus, ventral view; C. Endogyne, lateral view. Abbreviations: S—spermatheca. Scale bars: A–B=0.2mm; C=0.05mm.