Macracantha arcuata (Fabricius, 1793)

Macharoenboon, Kongkit, Siriwut, Warut & Jeratthitikul, Ekgachai, 2021, A review of the taxonomy of spiny-backed orb-weaving spiders of the subfamily Gasteracanthinae (Araneae, Araneidae) in Thailand, ZooKeys 1032, pp. 17-62 : 17

Macracantha arcuata (Fabricius, 1793) Figures 9A, B , 12A-C

Aranea arcuata Fabricius, 1793: 425. Type locality: East Indies.

Aranea arcuata Full list of synonyms and usage of the name available in World Spider Catalog (2020).

Material.

Thailand • 4 ♀ ; Krabi Province, Mueang District, Krabi Noi ; 08°07.45'N, 98°55.45'E; MUMNH-ARA-MAC002 • 1 ♀ ; Phang-nga Province, Thap Put District, 08°35.58'N, 98°40.08'E; MUMNH-ARA-MAC003 • 2 ♀ ; Nakhon Ratchasima Province, Pak Chong District ; 14°31.10'N, 101°24.00'E; MUMNH-ARA-MAC004 • 5 ♀ ; Krabi Province, Plai Phraya District, Khao Khao Hua Ling ; 08°30.88'N, 98°45.57'E; MUMNH-ARA-MAC005 • 1 ♀ ; Ranong Province, Mueang District, Hat Som paen; 09°57.55'N, 98°39.57'E; MUMNH-ARA-MAC007 • 4 ♀ ; Prachuap Khiri Khan Province, Bang Saphan District, Khao Ma Rong Cave ; 11°12.17'N, 99°29.65'E; MUMNH-ARA-MAC008 • 2 ♀ ; Phang-nga Province, Mueang District; 08°26.57'N, 98°30.95'E; MUMNH-ARA-MAC009 • 2 ♀ ; Phetchabun Province, Lom Sak District ; 16°43.74'N, 101°20.22'E; MUMNH-ARA-MAC010 • 2 ♀ ; Chiang Mai Province, Mae Rim District, Pong Yaeng ; 18°53.93'N, 98°51.58'E; MUMNH-ARA-MAC011 • 1 ♀ ; Nakhon Si Thammarat Province, Chang Klang District ; 08°19.27'N, 99°35.38'E; MUMNH-ARA-MAC012 • 4 ♀ ; Kanchanaburi Province, Sai Yok District ; 14°24.93'N, 98°52.53'E; MUMNH-ARA-MAC013 • 1 ♀ ; Chumphon Province, Mueang District, Ban Na ; 10°27.43'N, 99°02.58'E; MUMNH-ARA-MAC015 • 2 ♀ ; Mae Hong Son Province, Mae Sariang District, Mae Ho , 18°03.78'N, 98°02.20'E; MUMNH-ARA-MAC016 • 2 ♀ ; Chiang Mai Province, Mae Taeng District ; 19°10.71'N, 98°54.95'E; MUMNH-ARA-MAC017 • 3 ♀ ; Chumphon Province, Sawi District, Nam Lot Cave ; 10°14.03'N, 98°56.68'E; MUMNH-ARA-MAC019 • Chumphon Province, Mueang District, Wat Tham Sing ; 10°25.58'N, 99°03.63'E; MUMNH-ARA-MAC020 • 1 ♀ ; Chanthaburi Province, Laem Sing District ; 12°31.12'N, 102°10.23'E; MUMNH-ARA-MAC022 . Cambodia • 2 ♀ ; Cambodia Province , Kampot District; 10°34.92'N, 104°07.22'E; MUMNH-ARA-MAC021 .

Diagnosis.

Sternum black with yellow patches near anterior edge, coxae II and III, and the apex. Abdomen octagonal, orange, and slightly wider than long. Anterior edge of abdomen curved between anterior spines. Median spines very long, slender, and strongly arched, three times the abdomen width. Anterior and posterior spines poorly developed. Ventral side of abdomen orange. Spinnerets placed on strongly elevated black sclerotized structure. Ten anterior edge sigilla subequal in size. Four median sigilla arranged in a trapezoid. Ten posterior edge sigilla arranged in a straight line, closely spaced together. Outer posterior edge with nine sigilla: five sigilla placed near posterior spines, two sigilla on each side. Epigynum wider than long, with transparent median groove, visible in ventral view (Fig. 12B ). Scape tongue-shaped, with strongly recurved tip, visible in ventral view (Fig. 12B ). Spermathecae reniform (Fig. 12A ). Copulatory ducts bulging distally, encapsulated by sclerotized structure (Fig. 12A, C ). Fertilization ducts emerging posteriorly from spermathecae (Fig. 12A ).

Variation.

Two plain color morphs were found in this study, consisting of an orange morph (Fig. 9A ), and a white morph (Fig. 9B ). The orange morph was the most common, whereas the white morph was found rarely within some populations.

Distribution and habitat.

India, Sri Lanka, China, Myanmar, Malaysia, Thailand, Cambodia, and Indonesia (Java and Sumatra) ( Tikader 1982; Yin et al. 1997; World Spider Catalog 2020). Macracantha arcuata builds a vertical web under the shade of large trees or thick bushes. The female spider hangs at the underside of the web.

Figures

Figure 9. Females of A, B Macracantha arcuata and C, D M. hasselti showing dorsal view (left) and ventral view (right) A orange morph, specimen from Prachuap Khiri Khan (MUMNH-ARA-MAC 008) B white morph, specimen from Kanchanaburi (MUMNH-ARA-MAC 013 - W 1) C sharp spines morph, specimen from Saraburi (MUMNH-ARA-GAS 018) D long spines morph, specimen from Phetchaburi (MUMNH-ARA-GAS 025).

Figure 12. Female genitalia of A-C Macracantha arcuata D-I M. hasselti J-L Thelacantha brevispina. Genitalia are shown in dorsal view (A, D, G, J), ventral view from external (B, E, H, K), and posterior view (C, F, I, L).