''Carditamera affinis'' 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 ...

of marine

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusc 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 esti ...

. It was first described to science by George Brettingham Sowerby I in 1833. No English common name has been recorded for this species. The first appearance of this animal in the fossil record is 5.333 million years ago.

Description

The shell is roughly trapezoidal with 15 raised ribs. In some individuals, small spines or scales are found on the posterior ends (furthest from the hinge) of the larger ribs. The shell is colored in brown shades both on its exterior and interior. Shells have been recorded between 50.7mm and 101.2mm (2 to 4 inches) long.

Distribution

''Carditamera affinis'' is found in the eastern Pacific Ocean from

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

. It is also found in the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

and was one of the specimens collected there by

John Steinbeck John Ernst Steinbeck Jr. (; February 27, 1902 – December 20, 1968) was an American writer and the 1962 Nobel Prize in Literature winner "for his realistic and imaginative writings, combining as they do sympathetic humor and keen social ...

and Ed Ricketts, as recounted in ''

The Log From The Sea Of Cortez ''The Log from the Sea of Cortez'' is an English-language book written by American author John Steinbeck and published in 1951. It details a six-week (March 11 – April 20) marine specimen-collecting boat expedition he made in 1940 at variou ...

''. In 2012 a very similar looking species, ''Carditamera bajaensis'', was split from ''C. affinis''. Both species occur in the Gulf of California, but in different habitats. While ''C. affinis'' is

epifaunal Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zool ...

, that is it lives at the surface of the seabed on rocks and in crevices, ''C. bajaensis'' is infuanal or semi-infaunal, living completely or partly buried in sand, mud, or loose rocks. ''C. affinis'' is also found in the Galapagos Islands. This is a shallow-water species, living from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

down to 27 meters (90 feet) deep.

Life history

''Carditamera affinis'' is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

, straining nutrients from sea water that it pumps through its body. It is

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

as an adult, attaching itself to rocks and within crevices using a

byssus A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilid ...

. These animals can live as long as 17.25 years.

References

{{Taxonbar, from=Q13455189 Carditidae Bivalves of North America Bivalves described in 1833