Mosu dayan, Lin, Yucheng & Li, Shuqiang, 2013

Lin, Yucheng & Li, Shuqiang, 2013, Five new minute orb-weaving spiders of the family Mysmenidae from China (Araneae), Zootaxa 3670 (4), pp. 449-481 : 450-457

Mosu dayan new species

Figs 1–6 , 26

Type material: Holotype: male ( IZCAS), Dayan Cave (25°34.263´N, 110°36.594´E; altitude 355 m), Dayan Village, Hucheng Town, Xing’an County, Guangxi, China, 12 July 2009, Z.Y. Yao and C.X. Wang. Paratypes: 1 male and 3 females, same data as holotype ( IZCAS).

Etymology. The species epithet is a noun in apposition taken from the Dayan Cave, the locality of the collected types.

Diagnosis. The female of Mosu dayan n. sp. is similar to M. huogou Miller, Griswold & Yin, 2009 , but can be distinguished by the presence of a rounded copulatory basal stem, the presence of dorsal plate in posterior to the spermathecae, and the wide, sclerotized copulatory atrium ( Figs 3 B, 6B). The male can be distinguished by the presence of a long tibial apophysis and a large, long cymbial process ( Figs 2 A–C, 5A–C).

Description. Male: holotype ( Figs 1 A–C), total length 0.84. Prosoma 0.46 long, 0.46 wide, 0.30 high. Carapace of prosoma rounded, brown. Thoracic pars smooth, cephalic pars raised. Ocular area at apex, black, covered with few setae. Eight eyes in two rows. AME black, others white. AME, ALE and PLE round, PME ovate. In dorsal view, AER slightly recurved, PER straight, AER as wide as PER; ALE and PLE contiguous. All eyes surrounded by black rings. Clypeus 0.18 high, 5.2 x AME diameter; ALE separated by about 3.2 x its diameter from anterolateral edge of carapace. Chelicerae brown, slightly shorter than endites. Labium brown, fused to sternum, endites with serrula. Sternum 0.30 long, 0.29 wide, heart-shaped, dark brown, with a light vertical stripe in midline. Legs yellow brown, each segment lightest proximally. Leg formula: I-II-IV-III. Leg measurements: I 1.96 (0.63, 0.21, 0.45, 0.34, 0.34); II 1.66 (0.50, 0.20, 0.36, 0.27, 0.34); III 1.07 (0.34, 0.13, 0.20, 0.18, 0.23); IV 1.34 (0.43, 0.14, 0.29, 0.23, 0.25). Leg I with a ventral sclerotized spot on femur subdistally, a row of setae on tibia prolaterally, and a bent clasping spine on prolateral metatarsus ( Fig. 4 C). Patellae I–IV with a dorsally distal seta; tibiae I–IV with a dorsal proximal seta. Tibiae I–III with 3 trichobothria; tibia IV with 4 trichobothria. Opisthosoma 0.52 long, 0.48 wide, 0.68 high, round dorsally, dark brown, with a pair of white spots on abdominal dorsum.

Pedipalp large ( Figs 2 A–C; 5A–C). Femur without modification. Patella short, with a few setae. Tibia swollen, askew cup-shaped, covered with long setae, tibial brim extending to form a long retro-dorsal apophysis. Cymbium membranous, translucent, with a sclerotized long process and a cluster of long setae on cymbial fold. Subtegulum smooth, distinctly sclerotized. Tegulum membranous, rugose. Spermatic duct visible through wrinkled tegulum. Embolus long, coiling into two loops under tegulum and reaching to distal cymbium.

Female: Total length 1.09 (one of paratypes) ( Figs 1 D–F). Prosoma 0.52 long, 0.48 wide, 0.23 high. Coloration and shape same as in male but cephalic pars lower. Clypeus 0.11 high, distinctly lower than in male. Sternum 0.32 long, 0.30 wide. Leg formula: I-II-IV-III. Leg measurements: I 2.13 (0.71, 0.21, 0.50, 0.36, 0.34); II 1.73 (0.55, 0.20, 0.39, 0.29, 0.30); III 1.23 (0.38, 0.16, 0.23, 0.21, 0.25); IV 1.55 (0.52, 0.16, 0.34, 0.27, 0.27). Femora I and II with a ventral sclerotized spot distally. Setae and trichobothria of each leg as in male except for lacking a row of tibial setae and a metatarsal clasping spine on prolateral leg I. Opisthosoma as in male, 0.71 long, 0.71 wide, 0.89 high.

Epigynum rugose ( Figs 3 A–B, 4A–B, 6A–B), covered with long setae, margin posteriorly protruded. Internally with complex dorsal plates posterior to spermathecae. Spermathecae egg-shaped, strongly sclerotized. Fertilization ducts short, deriving from inner side of spermathecae. Copulatory ducts intricate, with looped and coiled trajectory, arising from lateral spermathecae, forming a membranous sac on dorsal spermathecae, extending to ventral spermathecae. Sclerotised copulatory ducts connected with atrium, attaching to a rounded copulatory basal stem. Copulatory opening situated at posterior margin of epigynum.

Variation. The total length ranges from 0.82 to 0.84 in males (n = 2) and from 1.04 to 1.11 in females (n = 3).

Distribution. Known only from the type locality ( Fig. 26 ).

Figures

FIGURE 1. Mosu dayan n. sp., male holotype (A – C) and female paratype (D – F). A – C. Habitus, D – F. Ditto. A, D dorsal view; B, E ventral view; C, F lateral view.

FIGURE 2. Mosu dayan n. sp., male holotype. A. Left pedipalp, prolateral view; B. Ditto, retrolateral view; C. Ditto, apical view. Abbrs.: CB = cymbium, CP = cymbial process, E = embolus, SD = spermatic duct, T = tegulum, TA = tibial apophysis, TI = tibia.

FIGURE 3. Mosu dayan n. sp., female paratype. A. Epigynum, ventral view; B. Vulva (lactic acid-treated), dorsal view. Abbrs.: CBS = copulatory basal stem, CD = copulatory duct, CO = copulatory opening, DP = dorsal plate, FD = fertilization duct, S = spermatheca.

FIGURE 4. Mosu dayan n. sp., male holotype (C) and female paratype (A, B). A. Epigynum, ventral view; B. Ditto, lateral view; C. Male left leg I, prolateral view. Abbrs.: CS = clasping spine, FS = femoral spot, TS = tibial spines.

FIGURE 5. Mosu dayan n. sp., male holotype. A. Left pedipalp, prolateral view; B. Ditto, retrolateral view; C. Ditto, apical view. Abbrs.: CB = cymbium, CP = cymbial process, E = embolus, T = tegulum, TA = tibial apophysis, TI = tibia.

FIGURE 6. Mosu dayan n. sp., female paratype. A. Epigynum, ventral view; B. Vulva (lactic acid-treated), dorsal view. Abbrs.: CBS = copulatory basal stem, CD = copulatory duct, CO = copulatory opening, DP = dorsal plate, FD = fertilization duct, S = spermatheca.

FIGURE 26. The locality records of five new mysemids from China. 1. Mosu dayan n. sp.; 2. Mosu tanjia n. sp.; 3. Mysmena baoxingensis n. sp.; 4. Mysmenella yinae n. sp.; 5. Trogloneta uncata n. sp..