Macracantha arcuata ( Fabricius, 1793 )

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 : 47

Macracantha arcuata ( Fabricius, 1793)

( Figs. 1G ; 11 A−E)

Aranea arcuata Fabricius, 1793: 425

Gasteracantha arcuata Dahl, 1914: 242 , fig. 1

Gasteracantha arcuata C. L. Koch, 1837: 34 , fig. 270

Gasteracantha arcuata Yin et al., 1997: 94 , figs. 23a−c

Gasteracantha arcuata Song, Zhu & Chen, 1999: 281 , figs. 167N−P, 168A, B, O

Material examined. MALAYSIA. 2 females (reg. UIR031014- MARC1 &2), Sungai Tekala, Hulu Langat ,

Selangor, coll. Tan J and Chan ZY, 3 Oct.2014; 1 female (reg. UIR270615- MARC3 ), Sungai Sedim , Kedah, coll. Tan J and Chan ZY, 27 June.2015 .

Diagnosis. Adult female Macracantha arcuata is differentiated from those of Actinacantha globulata and Gasteracantha hasselti based on the unique long median spines that are multiple times the width of the abdomen.

Natural history. Female individuals were collected in the understorey of disturbed forests, where they resided in an inverted position at the center of their horizontal webs built directly above or near (<2 m) water bodies. The reddishorange abdominal color was observed to fade with age, turning white. The long abdominal spines of females retain some flexibility post-molt and are angled farther apart in gravid and satiated individuals. Males not observed and female populations appeared to be seasonal.

Distribution. India, China, and Southeast Asia.

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. 11. Epigynal structure of Macracantha arcuata (Fabricius, 1793). A, Ventral view; B, Posterior view; C, Lateral view; D, Dorsal view; E, Anterior view. Scale = 100 µm. CO = Copulatory opening; FD = Fertilisation duct; S = Spermatheca.