''Krynickillus melanocephalus'' is a species 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

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

Agriolimacidae ''Agriolimacidae'' is a family of small and medium-sized land slugs, or shell-less snails, terrestrial molluscs, terrestrial pulmonate gastropod mollusc, mollusks. Distribution Distribution of Limacidae is Holarctic, this include: Nearctic, wes ...

. It is an invasive species, spreading from regions around the Black Sea to Northern and Central Europe.

Identification

The species resembles in form other agriolimacid slugs (notably ''

Deroceras ''Deroceras'' is a Taxonomy (biology), taxonomic genus of small to medium sized air-breathing land slugs in the family Agriolimacidae. Description Most species reach only 30–35 mm in length (max 45 mm). Coloration varies cons ...

''), so has 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 ...

in the rear half of the

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

and a tapering tail without a marked keel. However, it grows larger than ''Deroceras'' species (60 mm or occasionally more). The most distinctive feature is the deep black tentacles, head, and nape, with the dark colouration still visible under the front of the mantle. The congener ''Krynickillus urbanskii'' (Wiktor, 1971), occurring in Romania, Bulgaria and Turkey, has a paler black head and a pale nape.

Distribution

The natural range of ''Krynickillus melanocephalus'' is the Caucasus, Crimea, eastern

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

and northern Iran. It has been introduced more widely within Europe: further parts of Ukraine (e.g. Kyiv), further parts of Russia (Moscow, Novgorod and Tverskaya oblasts),

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

(since 1994),

Latvia Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...

(since 1997), Belarus (since 2009), Sweden (since 2015), Lithuania (since 2017), Finland (since 2017), Hungary (since 2019), Slovakia (since 2020), and Estonia. Krynickillus melanocephalus HU

Ecology

In its introduced range the species becomes adult in autumn and dies off in winter. It has spread from gardens to adjacent habitats, including woodland and meadows. Although it has sometimes been reported as a pest of crops, others have suggested that a diet of algae, fallen fruit, and fungi makes it less of a threat. In its native range this is a forest species.

References

{{Taxonbar, from=Q14635695 Agriolimacidae Gastropods described in 1851