Probolomyrmex watanabei Tanaka, 1974

Material examined. Bukit Timah Nature Reserve, 4 Jul 1969, D.H. Murphy leg., D12-6, ZRC _HYM_0000017; Central Catchment Nature Reserve, 24 Aug 2011, E.J.Y. Soh leg., CASENT0317191, ZRC _ ENT00048018 ; queen, Mandai Lake Road, Northern Node, 1°24’36.5”N, 103°47’04.0”, 53 m, 18 July 2019, J.S. Tan & N. Chin leg., Winkler extraction, ZRC _ ENT00028309 ; queen and workers, Seletar Trail, 1.39151, 103.80056, 16 Apr 2016, M.K.L. Wong leg., Winkler extraction, ZRC _ ENT00000676 .

Material not physical ly examined. ANIC 32-030944, D9-1/A124-7 (ANIC); CASENT0172416, D8-1 (ANIC).

Literature. None. New record.

Localities. Bukit Timah Nature Reserve; Central Catchment Nature Reserve; Mandai Lake Road; Seletar.

Habitat/Ecology. This species was found in primary and/or old/mature secondary forests in Singapore. Individuals were mostly collected from leaf litter.

Remarks. Some specimens examined were observed to have petiole in profile elongate with nearly flat dorsal margin, closely resemblant of Probolomyrmex itoi or P. longiscapus . However, the same specimens in dorsal view each had posterodorsal margin of petiole medially produced into a horn, a feature unique to and diagnostic of P. watanabei .