Diacamma rugosum var. ovalis Chapman & Capco, 1951: 56 (w.) VIETNAM. Indomalaya.

Primary type information: Primary type material: holotype workers. Primary type locality: Vietnam (“Südannam”): Danlac Prov., Ba-Me-Thuot, 700 m., 1930-31, Nr.5920 (K.N. Davydov). Primary type depository: SIZK. Type notes: 1) Holotype confirmed in SIZK by Radchenko et al., 2023: 16. 2) Radchenko et al., 2023: 16, say the number on the specimen currently labelled as holotype is 5720 (not 5920), and there is a note “not a type! W.L. Brown, 1994”.