Systaria mengla ( Song & Zhu, 1994 ) Song & Zhu, 1994

Zhang, Feng, Fu, Jianying & Zhu, Mingsheng, 2009, First report of the sac spider genus Systaria Simon (Araneae: Clubionidae) from China: Systaria hainanensis sp. nov. and Systaria mengla (Song & Zhu, 1994) comb. nov., Zootaxa 2305, pp. 51-60 : 57-59

Systaria mengla ( Song & Zhu, 1994) comb. nov.

( Figs 13–19 )

Itatsina mengla Song & Zhu 1994: 42 , figs 7A–B; Song et al. 1999: 402, figs 238G–H.

Type material. Holotype female, CHINA: Yunnan Province, Mengla County, Caiyun Cave [21.48°N, 101.56°E], 19 April 1992, deposited in IZCAS.

Diagnosis. This species resembles Systaria insulana , but can easily be distinguished from the latter by: (1) the central epigynal atrium that is distinctly larger than that of the latter; (2) chelicerae with two retromarginal teeth, while three retromarginal teeth are found in the latter.

Redescription. Female (holotype). Total length 7.87; cephalothorax 3.51 long, 2.34 wide; abdomen 4.36 long, 2.52 wide. Carapace ( Fig. 13 ) yellow-brown, darker in eye area; longitudinal ovoid, cephalic area relatively broad; fovea longitudinal and distinct. Eye diameters: AME 0.11, ALE 0.09, PME 0.08, PLE 0.08; eye interdistances: AME–AME 0.15, AME–ALE 0.12, PME–PME 0.18, PME–PLE 0.15, ALE–PLE 0.12; MOA 0.25 long, anterior width 0.23, posterior width 0.26. AER slightly recurved ( Fig. 14 ), PER slightly procurved and longer than AER. Clypeal height 0.11, equal to the diameter of AME. Chelicerae ( Fig. 16 ) moderately long, brown, with three promarginal and two retromarginal teeth. Endites ( Fig. 15 ) and labium yellowish-brown. Endites widest anteriorly, with a tuft of setae prolaterally. Labium long as wide, tip rounded and with several setae. Sternum ( Fig. 15 ) light brown, shield-shaped, not rebordered, with single sclerotised extensions to each coxa; anterior margin truncate and posterior margin not extending between coxae IV, only slightly narrower in front than in the middle. Legs light brown, leg spination: femora: I d1-1-1, r0-0-2; II d1- 1-1, r1-1-1, v0-0-1; III d1-1-0, p0-1-1, r1-1-1; IV d1-1-1, p0-0-1, r1-1-1; tibiae: I v2 -0-0; II v1 -0-0; III d1-0-0, p0-1-1, r0-1-1, v2-2 -2; IV d1-0-0, p0-1-1, r0-1-1, v2-2 -0; metatarsi: I v2 -0-0; II v2 -0-0; III p1-2-2, r1-2-2, v2- 2 -2; IV p1-2-2, r1-2-2, v2-2 -2. Leg formula: 4123 (Table 3).

Abdomen ( Fig. 13 ) ovoid, yellow-brown, slightly darker centrally; covered with long and dark setae, without muscular impressions centrally. Venter of abdomen light brown. ALS ( Fig. 17 ) cylindrical, slightly tapering, separated almost by more than half of their diameter. PMS thin and conical, as long as anterior spinnerets. PLS with distal segment shorter than basal segment, tapering; and basal segment of PLS with similar length as basal segment of ALS. Tracheal spiracle located just anterior to the spinnerets.

Epigynum ( Figs 18–19 ) with weakly sclerotised epigynal plate, epigynal atrium large and central, with arched anterior margin, two copulatory openings concave, located postero-medially near the posterior margin of atrium. Bursae situated anterior of copulatory openings, large sac-shaped and semi-transparent. Spermathecae globular, distinctly smaller than bursae, situated posteriorly and near the genital furrow; connecting with the copulatory opening through a wide duct; fertilization ducts short, arising from the postero-central ends of the spermathecae.

Distribution. Yunnan Province, China ( Fig. 20 ).

Remarks. Itatsina mengla was described by Song & Zhu (1994) based on a single female holotype collected from Cave Caiyun, Mengla County, Yunnan Province, China. No male has so far been found. Song et al. (1999) reproduced the illustrations from Song & Zhu (1994).

When we borrowed and examined the female holotype (No. IZCAS-Ar 9221) from the Institute of Zoology, Chinese Academy of Sciences (IZCAS), Beijing, we found the general appearance of this specimen to conform to the diagnosis of the Systariinae. The holotype has enlarged AME, slightly procurved PER, widely separated and slightly tapering ALS, an elongated distal segment of PLS, and the genital organs were very similar to those of Systaria bohorokensis . Furthermore, Itatsina mengla was collected from Cave Caiyun (Yunnan Province). The cave habitat of this species is consistent with the preferred habitat of many species of Systaria as described by Deeleman-Reinhold (2001, p. 204), “Most specimens were found in primary forest, leaf litter or under bark, often in caves, those found in caves fail to show morphological adaptation to lightless conditions”. We therefore transfer the species Itatsina mengla Song & Zhu, 1994 from Itatsina (Liocranidae) to Systaria (Clubionidae) , S. mengla ( Song & Zhu, 1994) comb. nov.

Figures

FIGURE 20. Distribution records of Systaria in China.

FIGURES 13 – 19. Systaria mengla (Song & Zhu, 1994) comb. nov., female holotype. 13. Female body, dorsal view. 14. Eye region of female, dorsal view. 15. Endites, labium and sternum of female, ventral view. 16. Left chelicera of female, posterior view. 17. Spinnerets, ventral view. 18. Epigynum, ventral view. 19. Vulva, dorsal view. B—bursa; COcopulatory opening; S—spermatheca. Scale bars: 1 mm (13 – 17); 0.5 mm (18 – 19).