[2] There is still ongoing disagreement whether it is more appropriate to consider Ambigolimax as merely a subgenus of Lehmannia; the evidence for splitting them is phylogenetic trees constructed on the basis of DNA sequences.

[3] Previous usage of the name Ambigolimax nyctelius has now been shown to refer to several species that had been confused: A. parvipenis, A. waterstoni, and Lehmannia carpatica.

[3][8] Ambigolimax was constructed by Pollonera in 1887[1] to encompass A. valentianus and what he called A. fulvus but is now understood to be Malacolimax tenellus.

[9] He considered Ambigolimax as a subgenus of Agriolimax (now Deroceras) in the family Agriolimacidae.

This splitting was based on the genetic evidence that the position of Malacolimax in the phylogenetic tree makes Lehmannia s.l.