Systolederus cinereus Brunner von Wattenwyl, 1893

(Figs. 18–20)

Systolederus cinereus Brunner von Wattenwyl, 1893: 105 (holotype —female, Myanmar, Carin Cheba [= Karen Hills]; in the Natural History Museum of Genova).

Systolederus cinereus — Kirby, 1910: 20; Kirby, 1914: 44; Günther, 1939: 170; Blackith, 1992: 171; Mahmood et al., 2007: 1282; Storozhenko & Dawwrueng, 2015: 536.

Systolederus ridleyi Hancock, 1909: 401 (holotype —female, Singapore, Singapore Botanical Garden; in the Oxford University Museum of Natural History, UK), syn. nov.

Teredorus ridleyi — Hancock, 1915: 110.

Systolederus ridleyi — Günther, 1939: 169; Blackith, 1992: 174; Devriese & Husemann, 2023: 340.

Material examined. VIETNAM, Th ừa Thiên Hu ễ province, Bạch Mã National Park: •5Ô and 3♀; open stream near Bạch Mã National Park, N16.22036 E107.88702, 72.9± 6.3 m.a.s.l.; 8 March 2023, 11h01; on a boulder or rock; coll. M.K. Tan & V. T . Trung; VIET . 23.31–38 (ZRC) •1Ô; along stream near Bạch Mã National Park, N16.22419 E107.88233, 57.4± 4.5 m.a.s.l.; 8 March 2023, 19h37; on a tree trunk; coll. M.K. Tan & V. T . Trung; VIET .23.50 (VNMN).

Remarks. Images of the holotypes of C. cinereus and C. ridleyi are available in the internet catalogue Orthoptera Species File (Cigliano et al., 2023). The comparison of original descriptions and photos of both species, as well as all materials examined by Sergey Yu. Storozhenko from Southeast Asia, allows proposing a new synonymy: Systolederus cinereus Brunner von Wattenwyl, 1893 = Systolederus ridleyi Hancock, 1909, syn. nov. The specimens from Bạch Mã National Park represent the first record of this species in Vietnam.

Ecology. This species was found along rivers, on rocks and substrate near the fast-flowing water. Nevertheless, it has also been found along forest edges near a river and dwelling among tree trunks.

Distribution. Myanmar, Thailand, Malaysia, Singapore; Vietnam: Thừa Thiên Huễ Province, Bạch Mã National Park [new].

Type locality. Myanmar, Carin Cheba .