''Alderia modesta'' 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), ...

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

, a marine

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 ...

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

in the family

Limapontiidae Limapontiidae is a taxonomic family of small to minute sacoglossan sea slugs. These are marine opisthobranch gastropod mollusks.Bouchet, P.; Gofas, S. (2011). Limapontiidae. Accessed through: World Register of Marine Species at http://www.marin ...

. It is found in estuarine habitats and saltmarshes on either side of the North Atlantic and the North Pacific Oceans.

Description

''Alderia. modesta'' grows to a length of about when fully expanded. The foot is broader than the body, and the sides and upper surface, apart for the front third, are covered with

cerata :''The tortrix moth genus ''Cerata'' is considered a junior synonym of ''Cydia (genus), Cydia. Cerata, singular ceras, are anatomical structures found externally in nudibranch sea slugs, especially in aeolid nudibranchs, marine animal, marine opi ...

(finger-like outgrowths). In young individuals these are organised in up to seven rows, but in adults, the rows are no longer apparent. The anus is set on a papilla on the upper surface near the rear. The integument is translucent, and the branching gut and digestive gland can be seen through the cerata and the surface of the foot. The cerata are involved in respiration and pulsate regularly; this helps move the blood around the body, there being no heart in this genus. The general colour of this sea slug is pale fawn, blotched with brown, green and white.

Distribution and habitat

The range includes both sides of the

North Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for ...

; in

Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

its range extends from

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

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 ...

and in North America, from

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

New York State New York, also called New York State, is a state in the northeastern United States. Bordered by New England to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and ...

. It also occurs on the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas North America Countries on the western side of North America have a Pacific coast as their western or south-western border. One of th ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

from

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and in

northeastern Asia Northeast Asia or Northeastern Asia is a geographical subregion of Asia. Its northeastern landmass and islands are bounded by the North Pacific Ocean. The term Northeast Asia was popularized during the 1930s by American historian and political s ...

where it is present in

Peter the Great Gulf The Peter the Great Gulf (Russian: Залив Петра Великого) is a gulf on the southern coast of Primorsky Krai, Russia, and the largest gulf of the Sea of Japan. The gulf extends for from the Russian–North Korean border, at the ...

and the

Yellow Sea The Yellow Sea, also known as the North Sea, is a marginal sea of the Western Pacific Ocean located between mainland China and the Korean Peninsula, and can be considered the northwestern part of the East China Sea. Names It is one of four ...

. Its habitat is tidal saltmarshes and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

Ecology

euryhaline Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus m ...

species, ''A. modesta'' is able to tolerate a wide range of

salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ...

. It is nearly always associated with the yellow-green alga '' Vaucheria litorea'' on which it feeds in

saltmarshes A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It i ...

. Its

eyesight Visual perception is the ability to detect light and use it to form an image of the surrounding environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual perception can be enabled by ph ...

is poor and in order to breed, individuals probably locate each other by smell and touch. Having found a partner, they push against each other and probe each other with their oral tentacles. They then each extend their

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

, which is armed with a sharp stylet, and push this through the body wall of the partner and transfer

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

by hypodermic injection. The

gonad A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...

occupies most of the body interior, and the injection can be anywhere on the body wall. Reciprocal injections usually take place at the same time, especially in larger individuals. These sea slugs are able to transfer sperm in this way within two days of

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

when only long.

References

{{Taxonbar, from=Q3804979 Limapontiidae Gastropods described in 1844