The following taxon apparently lies within the circumscription of Acrochaetium secundatum but has not yet been transferred or reduced to synonymy:
Chantransia virgatula (Harvey) Thuret forma tetrica Rosenvinge, 1909: 111–112, fig. 38 (syntype localities: various in Denmark).
Acrochaetium virgatulum (Harvey) Batters forma tetricum (Rosenvinge) G. Hamel, 1927: 97 (`tetrica').—Desikachary, V. Krishnamurthy, & M. Balakrishnan, 1990: 57–58, figs. 7F–I.
INDIAN OCEAN DISTRIBUTION: Sri Lanka.