Ambigolimax waterstoni is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the family Limacidae.

Waterston wrote his undergraduate thesis describing a species of "Limax" from the Royal Botanic Garden Edinburgh.

Waterston, with the holotype being one of his specimens from the Royal Botanic Garden Edinburgh, still preserved in the National Museum of Scotland.

Additional historical occurrences are in the Edinburgh and perhaps Glasgow botanic gardens, and probably on imported palms in Washington DC.

[4] Like other limacids, the animals are slim with a pointed tail, and the pneumostome lies in the posterior half of the mantle.