Songthela serriformis sp. nov.

Figure 5

Holotype. Male (XUX-2012-245, matured on 13 June 2013), China, Chongqing Municipality, Nan’an District, Nanshan Botanic Garden, 29.56ºN, 106.62ºE, 554 m a.s.l., 18 November 2012, collected by D Li, FX Liu, X Xu.

Paratypes. 1 male (XUX-2012-241A, matured on 22 March 2013) and 8 females (XUX-2012-237/238/239/240/2 41/242/243/244), same data as for holotype, 551–554 m a.s.l.

Diagnosis. Males of S. serriformis sp. nov. can be distinguished from S. pluma, S. tianzhu, S. xiangnan and S. yuping by apical spine of conductor with a spinule basally, conductor forms a lamina with dentate edge proximally (Fig. 5A, B, E); from S. jinyun sp. nov., S. longbao sp. nov. and S. wangerbao sp. nov. by conductor with slender apical spine and dentate edge proximally (Fig. 5A, B, E); from other Songthela species by conductor with one apical spine and a dentate edge proximally (Fig. 5A, B, E). Females of S. serriformis sp. nov. differ from S. tianzhu by middle genital stalks longer and posterior part of genital area wider (Fig. 5H–M); from S. yuping by middle receptacular clusters lager than lateral ones and with longer genital stalks (Fig. 5H–J); from S. jinyun sp. nov., S. longbao sp. nov., S. wangerbao sp. nov. and other Songthela species by four receptacular clusters situated on dorsal wall of bursa copulatrix, and posterior margin of bursa copulatrix sclerotised (Fig. 5H–M).

Description. Male holotype (XUX-2012-245). In alcohol, carapace yellowish-brown covered with a few hairs running over ocular area; opisthosoma brown with 12 dark brown tergites, close to each other, with two pointed hairs on tergites from second to fourth, second to sixth larger than remaining, the fourth largest; sternum narrow, much longer than wide; chelicerae robust with promargin of cheliceral groove with 8 denticles of variable size; legs with hairs/spines; 7 spinnerets. Measurements: BL 15.60, CL 6.95, CW 6.91, OL 8.90, OW 8.00; ALE> PLE> PME> AME; leg I 22.08 (6.11 + 2.80 + 4.55 + 5.82 + 2.80), leg II 22.79 (6.00 + 2.85 + 4.55 + 6.47 +2.92), leg III 24.88 (5.98 + 2.90 + 4.75 + 7.55 + 3.70), leg IV 31.00 (7.28 + 3.22 + 6.12 + 9.88 + 4.50).

Palp: Paracymbium unpigmented and unsclerotized prolaterally, with numerous setae and spines on tip (Fig. 5A– C). Contrategulum with a regular denticulate margin (Fig. 5A, B, D). Tegulum with a helicoid marginal apophysis and dorsal extension of terminal apophysis, a platelike terminal apophysis retrolaterally (Fig. 5C, F, G). Conductor fused with embolus basally, gradually narrowing to a long apical spine with a spinule basally, forming a lamina with a dentate edge proximally (Fig. 5A, B, E). Embolus with a transparent, wide and flat opening, a distinct shrink near the opening ventrally, with numerous ribbed ridges retrolaterally (Fig. 5A, B, D, E).

Female paratype (XUX-2012-244). In alcohol, carapace dark red-brown covered with a few hairs running over ocular area; opisthosoma light brown with 12 dark brown tergites, close to each other, with two pointed hairs on tergites from second to fourth, second to sixth larger than others, fourth largest; sternum narrow, much longer than wide; chelicerae robust with promargin of cheliceral groove with 12 denticles of variable size; legs with hairs/ spines; 8 spinnerets. Measurements: BL 14.05, CL 7.17, CW 5.91, OL 6.98, OW 5.68; ALE> PLE> PME> AME; palp 11.86 (4.10 + 1.95 + 2.53 + 3.28), leg I 13.49 (4.38 + 2.32 + 2.65 + 2.59 + 1.55), leg II 13.07 (4.27 + 2.22 + 2.47 + 2.53 +1.58), leg III 14.17 (4.05 + 2.33 + 2.51 + 3.31 + 1.97), leg IV 20.66 (5.58 + 2.87 + 3.75 + 5.53 + 2.93).

Female genitalia: Four receptacular clusters situated on dorsal wall of bursa copulatrix. Middle pair with long genital stalks, larger than lateral ones. Lateral pair with obscure genital stalks situated more dorsally, posterior margin of bursa copulatrix sclerotised (Fig. 5H–M).

Variation. Males and females vary in body size. The range of measurements in males as follow (N = 2): BL 13.51–15.60, CL 6.27–6.95, CW 6.12–6.91, OL 6.64–8.90, OW 5.60–8.00; females (N = 8): BL 10.19–18.12, CL 5.45–8.88, CW 5.07–7.68, OL 6.07–9.68, OW 4.26–7.05. The number of promargin of cheliceral groove varies from 8 to 12 (N = 10). There are 7 or 8 spinnerets. In addition, the conductor of males shows intraspecific variation: apical spine slightly curved with a spinule basally and forming a smooth lamina with a dentate edge proximally (Fig. 5A, B), or apical spine straight without spinule basally, and the formed lamina covered with several teeth (Fig. 5D, E). Female genitalia also show intraspecific variation: length of middle genital stalks is different (Fig. 5H–J); lateral receptacular clusters are distinctly smaller than middle ones (Fig. 5I) compared with the other samples (Fig. 5H, J), posterior margin of genital area trapezoid (Fig. 5K, L) or W-shaped (Fig. 5M).

Etymology. The species epithet is an adjective from the combination of the Latin serri (serrate) and formis (shaped), and refers to the serrated margin of conductor proximally.

Distribution. Chongqing (Nan’an), China.

GenBank accession number. Holotype: XUX-2012-245: OL982297.