''Crepidula convexa'' 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 snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, 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 ...

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 Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Calyptraeidae The Calyptraeidae are a family of small to medium-sized marine prosobranch gastropods.MolluscaBase. Calyptraeidae Lamarck, 1809. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=141 on ...

, the slipper snails or slipper limpets, cup-and-saucer snails, and Chinese hat snails. The maximum recorded

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 ...

length is 20 mm.

Distribution

This species is native to the eastern coasts of

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...

and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, from

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

Habitat

The minimum recorded depth at which this species has been found is 0 m (i.e. at the sea surface); the maximum recorded depth is 70 m.

Location

''Crepidula convexa'' can be found along the east coast of North America. Geographically they can be found in the low

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

(5 to 10 meters) and to roughly about 200 meters down into the shallow subtidal zone. They are predominantly found on rocks, shells and sea grass.

Description

The shell of the ''Crepidula convexa'' can be described as oval-shaped. This is mostly due to the shell needing to meet the needs of its environment. They vary depending on their exact location being in sea grass or in rocks. Those located in sea grass are oftentimes smaller and have a steeper arch then their counterparts located in rocky areas. The snail varies in shades of cocoa, often having spots or streaks on the shell. Rarely do some have purple tints near the apex. The shelf is flat or slightly convex and the left side extends farther forward than it does the right side. The typical maximum ''Crepidula convexa'' will grow up to 20 mm in length.

Development

''Crepidula convexa'' follows a

sequential hermaphroditism Sequential hermaphroditism (called dichogamy in botany) is one of the two types of hermaphroditism, the other type being simultaneous hermaphroditism. It occurs when the organism's sex changes at some point in its life. A sequential hermaphrodit ...

life cycle. During its life it will pass through five sexual phases. The immature phase is where it is in the larval stage and has no need to start sexual reproduction but shows a slight rise on the right side of the neck where the phallus will later grow. Next, when hatched the snail will be in what is called the "phallus bud" stage, which is the forming of the male sexual organ and may have a peg-like phallus. Soon after, it will have developed a full phallus and be deemed a male, where it can start the sexual reproduction process and fertilize its female counterparts. Later on it will start to change and grow into a "transitional" where the male starts to grow and loses the ability to fertilize and start to become female. Finally, it will be a female which will be its final sexual phase. At that point it will be able to be inseminated and lay eggs and may have a remnant of a degenerate phallus.

Reproduction

During a single breeding season the larger female will only have one male partner. On the other hand males may mate with multiple females. This increases the survivability rate of the species because there is always an abundance of females than males. The smaller males have greater mobility which allows them to mate more and increase reproductive capacity for the species in a given area.

Population structure

The genetic structure of ''Crepidula convexa'' differs distinctively based on the location of the species. The genetics of a specific snail of this species from Florida can be separated from another found in New England. Samples of ''Crepidula convexa'' in the south may have faster growth rates and thus shorter life spans due to higher pH levels, but it is still an arguable science as to why they have faster growth rate than their counterparts in other regions. These snails are not equipped to travel long distances to migrate. They live on the shells of other organisms, some being sea grass. This can be attributed to short distance gene flow. They may "piggyback" a ride on

horseshoe crab Horseshoe crabs are arthropods of the family Limulidae and the only surviving xiphosurans. Despite their name, they are not true crabs or even crustaceans; they are chelicerates, more closely related to arachnids like spiders, ticks, and scor ...

s to warmer regions they are not necessarily native to.

References

{{Taxonbar, from=Q3171638 Calyptraeidae Molluscs of the Atlantic Ocean Gastropods described in 1822 Taxa named by Thomas Say