Van Nieukerken et al 2016 synonymise the unavailable name Stigmella acerifoliella Dovnar-Zapolski, 1969 with acerna. The type mines were collected from Acer turcomanicum in Turmenistan, Kopet-Dag, the same type locality and host as for S. acerna and with a similar mine form. The paper by Dovnar-Zapolski (1969) is poorly known, but contains a number of new names for Nepticulidae and other leafminers, all based on the mine alone. They are therefore not available (ICZN art. 13.6.2), and in many cases it is impossible to determine the identity of these names with the little information provided, but they do provide some interesting records.
Syntypes mine, Turkmenistan: W. Kopet-Dag, mines on Acer turcomanicum