Lehmannia

These are narrow-bodied slugs up to 8 centimeters long. The mantle covers less than a third of the body length. They are cream-colored to brown or black, usually with at least two longitudinal stripes along the mantle. The sole of the foot is lightest in the middle. The penis is short compared to those of Limax, and in shape it may be "tubular, baggy, or claviform" (club-shaped).[2] The mucus is watery.[2]

Many species live in mountain habitat, where they can be found on trees and rocks and feed on lichens.[2] Other species (in particular those placed by some authorities in the genus Ambigolimax) are synanthropic and invasive.

There are about 18 species in the genus. Currently (2022) authorities disagree whether to split off some species into the genus Ambigolimax, as some phylogenies based on DNA sequences suggest is appropriate.[3] The following list defines Lehmannia in the broad sense (sensu lato), but indicates which species have been placed in Ambigolimax:[4][3]

• Lehmannia brunneri (H. Wagner, 1931)
• Lehmannia horezia Grossu & Lupu, 1962
• Lehmannia carpatica Hutchinson, Reise & Schlitt, 2022
• Lehmannia islandica Forcart, 1966
• Lehmannia janetscheki Forcart, 1966
• Lehmannia jaroslaviae Grossu, 1967
• Lehmannia macroflagellata Grossu et Lupu, 1962
• Lehmannia marginata (O.F. Müller, 1774) – tree slug (type species)
• Lehmannia medioflagellata Lupu, 1968
• Lehmannia melitensis (Lessona & Pollonera, 1882) = Ambigolimax melitensis according to [3]
• Lehmannia parvipenis = Ambigolimax parvipenis Hutchinson, Reise & Schlitt, 2022
• Lehmannia requienii Pollonera, 1896
• Lehmannia rupicola Lessona & Pollonera, 1882
• Lehmannia sarmizegetusae Grossu, 1970
• Lehmannia szigethyae Wiktor, 1975
• Lehmannia valentiana (Férussac, 1822) = Ambigolimax valentianus – Valencia slug, threeband garden slug
• Lehmannia vrancensis Lupu, 1973
• Lehmannia waterstoni = Ambigolimax waterstoni Hutchinson, Reise & Schlitt, 2022

Note that the name Lehmannia nyctelia (= Ambigolimax nyctelius) is no longer valid. The species originally given the species name is in the genus Letourneuxia, but the name has been mistakenly applied to three of the species listed above (L. carpatica, A. parvipenis and A. waterstoni).[3]