''Ambigolimax waterstoni'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family

Limacidae Limacidae, also known by their common name the keelback slugs, are a taxonomic family of medium-sized to very large, air-breathing land slugs, terrestrial pulmonate gastropod molluscs in the superfamily Limacoidea. Distribution The distr ...

Taxonomy

This is one of the several species formerly confused under the name ''Limax nyctelius'' and later ''Lehmannia nyctelia'' or ''Ambigolimax nyctelius''. In the early 1930s A.R. Waterston wrote his undergraduate thesis describing a species of "''Limax''" from the

Royal Botanic Garden Edinburgh The Royal Botanic Garden Edinburgh (RBGE) is a scientific centre for the study of plants, their diversity and conservation, as well as a popular tourist attraction. Founded in 1670 as a physic garden to grow medicinal plants, today it occupies ...

. These specimens and others were the basis for H.E. Quick in 1946 to name them as ''Limax nyctelius'', a species described from Algeria. By that time M. Connolly had used this name for the same species in South Africa. It was subsequently reported more widely. Only in 2022 was it realised that these further findings were not all of the same species: slugs from the

Carpathian Mountains The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains at . The range stretches ...

and Bulgaria were of a species now called '' Lehmannia carpatica'' and the recently invasive species in Western Europe and California has been renamed ''

Ambigolimax parvipenis ''Ambigolimax parvipenis'' is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the Limacidae. Taxonomy ''Ambigolimax parvipenis'' was first clearly characterised in 2014, based on specimens from the British ...

''. Furthermore, the original '' Limax nyctelius'' was recognised as a species of ''

Letourneuxia ''Letourneuxia'' is a genus of large air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Arionidae, the roundback slugs. Species This genus is monotypic, containing the single species * ''Letourneuxia nyctelia'' (Bo ...

''. Hence the species from Edinburgh has been renamed ''Ambigolimax waterstoni'', after A.R. Waterston, with the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

being one of his specimens from the Royal Botanic Garden Edinburgh, still preserved in the

National Museum of Scotland The National Museum of Scotland in Edinburgh, Scotland, was formed in 2006 with the merger of the new Museum of Scotland, with collections relating to Scottish antiquities, culture and history, and the adjacent Royal Scottish Museum (opened in ...

Distribution

The original home of ''A. waterstoni'' is likely Algeria. It is probably an introduction on the island of

Elba Elba ( it, isola d'Elba, ; la, Ilva) is a Mediterranean island in Tuscany, Italy, from the coastal town of Piombino on the Italian mainland, and the largest island of the Tuscan Archipelago. It is also part of the Arcipelago Toscano National ...

. In South Africa, Australia, and New Zealand it has spread outdoors quite widely. Additional historical occurrences are in the Edinburgh and perhaps Glasgow botanic gardens, and probably on imported palms in Washington DC.

Description

The length of preserved specimens reaches 37 mm. Like other limacids, the animals are slim with a pointed tail, and the

pneumostome The pneumostome or breathing pore is a respiratory opening of the external body anatomy of an air-breathing land slug or land snail. It is a part of the respiratory system of gastropods. It is an opening in the right side of the mantle of a ...

lies in the posterior half of the mantle. The background colour is pale yellowish to light brown, with a pale cream sole. Two darker lines run along either side of the mantle, and also posteriorly along the back, although fainter and perhaps not in all specimens. On these external features ''A. waterstoni'' is generally not distinguishable externally from other species of ''Ambigolimax'', so morphological identification requires dissection. The species is readily identifiable by its penis, which is long and lacks a penial appendage. These characters are shared by ''Lehmannia carpatica'', but the structures inside the retracted penis are distinct: ''Ambigolimax waterstoni'' has two flaps running most of the length of the penis with a distinctive honeycomb-like surface structure on the tissue between the flaps.

References

{{Taxonbar, from=Q113102419 waterstoni Gastropods described in 2022