Identification to species is based on the soldier but should be done by an expert as the characters are variable and identification should be based on localitry, nesting habits and measurements of the soldier.
May be confused with Coptotermes frenchi and C. lacteus. Distinguishing these three species is difficult and should be done by and expert. As a guide, the Coptotermes acinaciformis soldier is larger (5.0 - 6.5mm +- 0.8mm) than soldiers of C. frenchi (4.0 - 5.0mm +- 0.4mm) and C. lacteus (4.40 +- 0.4mm). As well, the head in dorsal view for C. frenchi and C. lacteus is "pear shaped" compared to a somewhat "rectangular" shape for C. acinaciformis.
Hadlington, P. (1987). Australian termites and other common timber pests. New South Wales Press