''Boettgerilla pallens'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

the worm slug, is a European

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, 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 ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. 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 o ...

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 inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Boettgerillidae ''Boettgerilla'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod molluscs in the family Boettgerillidae. The generic name ''Boettgerilla'' is named after the German malacologist Oskar Boettger. Taxonomy ''Boettgerilla ...

Distribution

The type locality of ''Boettgerilla pallens'' is

Gudauta Gudauta ( ka, გუდაუთა, ; , ''Gwdowtha''; , ''Gudauta'') is a town in Abkhazia, Georgia, and the capital of the eponymous district. It is situated on the Black Sea, 37 km northwest of Sokhumi, the capital of Abkhazia. It is the ...

Abkhazia Abkhazia, officially the Republic of Abkhazia, is a List of states with limited recognition, partially recognised state in the South Caucasus, on the eastern coast of the Black Sea, at the intersection of Eastern Europe and West Asia. It cover ...

.Kantor Yu I., Vinarski M. V., Schileyko A. A. & Sysoev A. V.(published online on December 22, 2009). "Catalogue of the continental mollusks of Russia and adjacent territories"
Version 2.3.
The native distribution of ''Boettgerilla pallens'' is believed to be the SW flank of the

Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...

: *

* western

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

Maybe it is also native to Armenia, the Crimean Mountains and Donetsk Upland in

Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...

.Balashov I.A. & Baidashnikov A.A. 201
"The first findings of a slug ''Boettgerilla pallens'' (Stylommatophora, Boettgerillidae) in Crimea"
Ruthenica. 22(2): 111-114. But the species has spread spectacularly over the last half century. Dates of first recorded occurrences in various countries are listed in Reise et al. (2000). In Europe, ''Boettgerilla pallens'' was first found in 1949 (in Germany). It has now become naturalized in most of Europe although it has conspicuously not been reported from most of Spain, Italy and the Balkan Peninsula. Countries where it occurs include: *

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

- since 1973 *

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

- since 1972 *

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

* Belgium *

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

. *

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

- since 1954, mainly in the south-western Poland *

Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

Lithuania Lithuania, officially the Republic of Lithuania, is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea, bordered by Latvia to the north, Belarus to the east and south, P ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

: Moscow, Saint Petersburg and other cities * Spain (north only) and Andorra * Italy (north only) * Romania * Slovenia – since 1994 * Serbia – since 2022 * Bulgaria – since 1999 *

Kyiv Kyiv, also Kiev, is the capital and most populous List of cities in Ukraine, city of Ukraine. Located in the north-central part of the country, it straddles both sides of the Dnieper, Dnieper River. As of 1 January 2022, its population was 2, ...

Lviv Lviv ( or ; ; ; see #Names and symbols, below for other names) is the largest city in western Ukraine, as well as the List of cities in Ukraine, fifth-largest city in Ukraine, with a population of It serves as the administrative centre of ...

Ivano-Frankivsk Ivano-Frankivsk (, ), formerly Stanyslaviv, Stanislav and Stanisławów, is a city in western Ukraine. It serves as the administrative centre of Ivano-Frankivsk Oblast as well as Ivano-Frankivsk Raion within the oblast. Ivano-Frankivsk also host ...

Vinnytsia Vinnytsia ( ; , ) is a city in west-central Ukraine, located on the banks of the Southern Bug. It serves as the administrative centre, administrative center of Vinnytsia Oblast. It is the largest city in the historic region of Podillia. It also s ...

, some cities of

Crimea Crimea ( ) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukrain ...

and others * Iceland Outside Europe it is also known, presumed as an introduction, from: * Western Siberia (Russia) *

Tajikistan Tajikistan, officially the Republic of Tajikistan, is a landlocked country in Central Asia. Dushanbe is the capital city, capital and most populous city. Tajikistan borders Afghanistan to the Afghanistan–Tajikistan border, south, Uzbekistan to ...

* Turkey * Canary Islands (Spain) * Canada: British Columbia, Newfoundland, Quebec * USA: California, Oregon * Mexico *

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Description

''Boettgerilla pallens'' is very narrow and slender slug, almost worm-like and sharply

keel The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a fluid dynamics, hydrodynamic and counterbalancing purpose as well. The keel laying, laying of the keel is often ...

ed. The color is pale greyish or with bluish hue. The head and keel is slightly darker. The mantle is pointed at its posterior end and equipped with fine concentrical grooves. Sole is pale yellow. Mucus is colourless. Juveniles are yellowish to dirty white. The body length is up to 60 mm. The width is up to 3 mm. The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

is small, fragile, 1.5–3 x 0.8–1.5 mm, with median nucleus and growth lines, denser in the posterior part, no thin margin, located below the very terminal section of the pointed end of the mantle.

Reproductive system The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are al ...

: Penis is elongate and broader than vagina, epiphallus and

spermatheca The spermatheca (pronounced : spermathecae ), also called ''receptaculum seminis'' (: ''receptacula seminis''), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, Oligochaeta worms and certain other in ...

. Epiphallus is swollen and connected to penis laterally near its posterior end, by a long thin duct, which is thinner than vas deferens. Vagina as long as penis and almost as narrow as vas deferens. There are no accessory glands. The spermatheca is elongate and relatively short. ''Boettgerilla pallens'' is much more slender than ''

Milax gagates ''Milax gagates'', known by the common name greenhouse slug, is a species of air-breathing, keeled, land slug, a shell-less terrestrial gastropod mollusc in the family Milacidae.Marshall, B. (2014). Milax gagates (Draparnaud, 1801). Accessed thr ...

''. The sole is more slender. In ''Milax gagates'' the posterior end of the mantle is rounded, its shell is larger and better visible, its colour more yellowish-brownish. Boettgerilla pallens 3

Ecology

Reise et al. (2000) review aspects of the distribution, mode of range expansion, and other aspects of its ecology. ''Boettgerilla pallens'' inhabits a very wide range of habitats, including gardens, grassland, coniferous and deciduous woodland, and is tolerant of a wide range of soil pH, calcium content and water content. It lives at altitudes of up to 1750 m in the Caucasus and in Switzerland at up to 1600 m, but usually below 700 m. It can be considered as

synanthropic A synanthrope (from ancient Greek σύν ''sýn'' "together, with" and ἄνθρωπος ''ánthrōpos'' "man") is an organism that evolved to live near humans and benefit from human settlements and their environmental modifications (see also ...

, although it is now often found also in undisturbed habitats. Although it may often been found under logs and stones, it is predominantly subterranean, adapted to moving through

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

burrows and similar spaces in soil, 2–20 cm (maximum up to 60 cm) below surface. Snails move rapidly away from bright light sources. Feeding is seldom intensive: slugs usually take a few bites (of earthworm faeces,

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

etc., also arionid eggs) and move on. Although often found in gardens and greenhouses, it has only rarely been considered a pest. One study reports it coming to the surface at night to predate snails. Mating and egg-laying is during late summer and into autumn in Britain (October in Germany). Eggs are laid 9–27 cm below the surface as several clutches of 1–6 eggs . Adults survive egg-laying but die shortly afterwards. Juveniles hatch after 20–22 days at 17 °C (in Germany), between October and December (in Britain). Juveniles turn colour from white to grey in May–June.

References

This article incorporates public domain text from the reference."Species summary for ''Boettgerilla pallens''"
.

AnimalBase AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and p ...

, last modified 28 December 2008, accessed 8 September 2010.

Distribution

Description

Ecology

References

Further reading