Gasteracantha diardi ( Lucas, 1835 )

Tan, Ji, Chan, Zi Yang, Ong, Ching Ang & Yong, Hoi Sen, 2019, Phylogenetic relationships of Actinacantha Simon, Gasteracantha Sundevall, Macracantha Hasselt and Thelacantha Simon spiny orbweavers (Araneae: Araneidae) in Peninsular Malaysia, Raffles Bulletin of Zoology 67, pp. 32-55 : 43-45

Gasteracantha diardi ( Lucas, 1835)

( Figs. 1 B−D, 5A−F)

Epeira diardi Lucas, 1835: 70 , pl. 149, fig. 4.

Gasteracantha pavesi O. Pickard-Cambridge, 1879: 282 , pl. 26, fig. 4.

Gasteracantha diardi Dahl, 1914: 285 .

Gasteracantha diardi Kolosváry, 1931: 1057 , pl. 30, fig. 1.

Material examined. MALAYSIA. 2 females (reg. UIR270115- GDIA1 &2), Penang Hill , Penang, coll. Tan J, 31 Oct.2013 ; 2 females (reg. UIR270115- GDIA3 &4), Gunung Jerai , Kedah, coll. Tan J and Chan ZY , 9 June. 2014 ; 2 females (reg. UIR270115- GDIA5 &6), Kuala Sepetang, Taiping , Perak, coll. Tan J and Chan ZY, 12 May.2014 .

Measurements (female). CL = 2.45; CW = 3.72; AL = 6.39; AW = 25.56 (including median spines); TL = 8.80. AS = 1.15; MS = 6.23; PS = 1.58.

Interocular distance. AME – AME = 0.21; ALE – AME = 1.44; ALE – ALE = 3.47; PME – PME = 0.26; PLE – PME = 1.36; PLE – PLE = 3.49; ALE – PLE = 0.04; AME – PME = 0.12.

Legs. I 10.47 (3.02, 1.40, 2.71, 1.76, 1.58); II 10.16 (3.00, 1.23, 2.39, 1.92, 1.62); III 7.50 (2.68, 0.83, 1.44, 1.51, 1.04); IV 12.80 (5.00, 1.28, 2.72, 2.48, 1.32). Leg formula 4123.

Diagnosis. Female individuals of G. diardi display tiny angular anterior abdominal spines and well-developed lateral median spines which may be straight or slightly bent backwards ( Lucas, 1835; Dahl, 1941). The epigyne of G. diardi is illustrated for the first time in Fig. 6 , which is shorter than wide and appears M-shaped in ventral view ( Fig. 6C ), with two tiny openings that extend internally and a forked septum with two apparent depressions.

Intraspecific variation. Two different abdominal patterns of female G. diardi were observed in this study: (i) darkcolored abdomen with three horizontally transverse stripes (white and yellow; Fig. 1C, D ) or (ii) without stripes ( Fig. 1B ). Both morphotypes display similar epigyne structure. Spine curvature and bristles more conspicuous in full adults.

RAFFLES BULLETIN OF ZOOLOGY 2019

Natural history. In Peninsular Malaysia, the dark form of female G. diardi ( Fig. 1B ) appeared to be prevalent in the highlands, while two striped female individuals ( Fig. 1C, D ) were collected from the fringes of a mangrove forest. The webs of female individuals were conspicuous and often constructed at 1−2 m above ground. Males not observed.

Distribution. China, Thailand, Malaysia, Borneo and Indonesia.

Figures

Fig. 1. General habitus. A, Actinacantha globulata (Walckenaer, 1841), sub-female; B, Gasteracantha diardi (Lucas, 1835), female; C, G. diardi yellow morph, female; D, G. diardi white morph, sub-female; E, G. kuhli, female; F, Gasteracantha hasselti C. L. Koch, 1837, female; G, Macracantha arcuata (Fabricius, 1793), female; H, Thelacantha brevispina (Doleschall, 1857), female; I, G. mengei Keyserling, 1864, female. Photos by Tan Ji.

Fig. 6. Gasteracantha diardi (Lucas, 1835). A, Dorsal habitus; B−E, Epigynal structure. A, Ventral view; B, Posterior view; C, Lateral view; D, Dorsal view; E, Anterior view. Scale A = 5 mm; B−E = 100 µm. S = Spermatheca.