''Laevicaulis alte'', or the tropical leatherleaf, is a

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), ...

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

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

Veronicellidae The Veronicellidae, also known by their common name the leatherleaf slugs, are a family of pulmonate terrestrial slugs. The herbivorous molluscs occur mainly in the tropical and subtropical areas of America, Asia and Africa. They act as interme ...

, the leatherleaf slugs.

Description

''Laevicaulis alte'' is a round, dark-coloured slug with no shell, long. Its skin is slightly tuberculated. The central

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 ...

is beige in colour. This slug has a unique, very narrow foot; juvenile specimens have a foot wide and adult specimens have a foot that is only wide. The

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s are small, long, and they are only rarely extended beyond the edge of the mantle.

Parasites

This slug is an intermediate host for ''

Angiostrongylus cantonensis ''Angiostrongylus cantonensis'' is a nematode (roundworm) parasite that causes angiostrongyliasis, an infection that is the most common cause of eosinophilic meningitis in Southeast Asia and the Pacific Basin. The nematode commonly resides in the ...

'', the rat lungworm, a round worm, the most common cause of eosinophilic meningoencephalitis.

Predators

''Laevicaulis alte'' is eaten by the frog '' Rana tigrina''.

Distribution

The species is probably indigenous to

sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...

, including

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

,Rowson B., Warren B. H. & Ngereza C. F. (2010). "Terrestrial molluscs of Pemba Island, Zanzibar, Tanzania, and its status as an "oceanic" island". ''

ZooKeys ''ZooKeys'' is a peer-reviewed open access scientific journal covering zoological taxonomy, phylogeny, and biogeography. It was established in 2008 and the founding editor-in-chief was Terry Erwin (Smithsonian Institution The Smithsonian ...

'' 70: 1-39.

Botswana Botswana, officially the Republic of Botswana, is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory part of the Kalahari Desert. It is bordered by South Africa to the sou ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

It has been introduced and has become an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

in the following areas: * Southern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Pratas Island Pratas Island,, United States National Geospatial-Intelligence Agency also known as the Tungsha Islands or the Dongsha Islands (), is a coral island situated in the northern part of the South China Sea administered as part of Cijin District, K ...

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Wu S.-P., Hwang C.-C., Huang H.-M., Chang H.-W., Lin Y.-S. & Lee P.-F. (2007).
Land Molluscan Fauna of the Dongsha Island with Twenty New Recorded Species
. ''Taiwania'' 52(2): 145–151
Original
*

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

(

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

) * Islands in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

(since 1889) *

Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...

The species is already established in the USA, and is considered to represent a potentially serious threat as a pest, an

which could negatively affect agriculture, natural ecosystems, human health or commerce. Therefore, it has been suggested that this species be given top national

quarantine A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...

significance in the USA.Cowie R. H., Dillon R. T., Robinson D. G. & Smith J. W. (2009). "Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment". ''American Malacological Bulletin'' 27: 113–132
PDF

Habitat

''Laevicaulis alte'' lives in dry areas, mostly at lower altitudes.

Life cycle

The slug hatches from eggs. ''Laevicaulis alte'' has several adaptations for living in dry conditions: a rounded shape with as small as possible surface area, and a narrow foot to reduce evaporation. Juvenile specimens search for food nearly always at night, and stay buried in the soil during the day. Larger specimens are active during the day sometimes. The slug can grow up from to approximately in length in 7 months.

References

External links

articles at PubMed

Distribution in United States

In English
an
in Chinese

Images

photo
(In Japanese)
''Laevicaulis alte''
at
Samoan Snail Project

(Japanese)
Photo
(Japanese)

(Japanese)

(Japanese)

Genome

Sequences 18S rRNA

Vernacular names
{{Taxonbar, from=Q3170495 Veronicellidae Gastropods described in 1822