''Crepidula convexa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

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 ...

mollusk 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 e ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Calyptraeidae, 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 ** Thin-shell structure Science Biology * Seashell, a hard ou ...

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 ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, from

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...

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

Description

The shell of the ''Crepidula convexa'' can be described as oval shape. This mostly due to the shell needing to meet the needs of its environment. They vary depending on the exact location of them being in sea grass or in the rocks. Those located in seagrass 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 then 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 a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...

life cycle. During its life it will pass through 5 sexual phases. The immature phase 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 seagrass. This can be attributed to short distance gene flow. They may “piggyback” a ride on

horseshoe crab Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachn ...

s to warmer regions they are not necessarily native too.

References

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