Bakevelliidae is an extinct

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

of prehistoric bivalves that lived from the Late Mississippian until the

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "da ...

.The Paleobiology Database Bakevelliidae entry
Retrieved 2 January 2012. Bakevelliidae species are found worldwide, excluding Antarctica. Living a stationary life attached to substrate in marine and brackish environments, they formed shells of an

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...

composition with a low amount of magnesium calcite. The family was named by King in 1850. At least one genus in the family, '' Hoernesia'', has a notably twisted commissure join.

Morphology

Generally the family consists of species with elongate shells with notably unequal

valves A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

. Some of the genera have lost the small anterior auricle but all lack a byssal notch. The shell structuring consists of a regular prismatic calcitic outer layer and an interior layering which is nacreous. The valve surfaces show multiple pits where the valve ligaments were attached. The valve dentition generally consisted of a series of short, transverse teeth along the anterior edge and a few more elongated teeth along the sides. Shells of the included genera range from having radial sculpturing to not having any radial sculpture. Several of the species have an early growth period in which the valve ligament is anchored in a single pit in the shell. When the species size exceeded approximately the ligament attachment would develop to encompass two or more pits. One possible species of Bakevelliid from the early Triassic of Utah is tentatively included in the genus '' Bakevellia'' but is noted for having an adult shell with only one ligament attachment pit, contrary to the normal state of the rest of the family.

Taxonomy

Taxonomy taken from The Paleobiology Database. Bakevelliidae King, 1850 *Genus '' Aguilerella'' Chavan, 1951 *Genus '' Aguileria'' White, 1887 *Genus '' Bakevellia'' King, 1848 **Subgenus ''Bakevellia (Bakevellia)'' King, 1848 **Subgenus ''Bakevellia (Boreiobakevellia)'' Kurushin, 1980 **Subgenus ''Bakevellia (Maizuria)'' Nakazawa, 1959 **Subgenus ''Bakevellia (Neobakevellia)'' Nakazawa, 1959 *Genus '' Cassiavellia'' Tëmkin & Pojeta, Jr., 2010 *Genus '' Costigervillia'' Cox, 1948 *Genus '' Cultriopsis'' *Genus '' Cuneigervillia'' Cox, 1954 *Genus '' Gervillaria'' Cox, 1951 *Genus '' Gervillella'' Waagen, 1907 *Genus '' Gervillia'' Defrance, 1820 **Subgenus ''Gervillia (Cultriopsis)'' Cossman, 1904 **Subgenus ''Gervillia (Gervillia)'' Defrance, 1820 *Genus '' Gervilliopsis'' Whitfield, 1885 *Genus '' Hoernesia'' **Subgenus ''Hoernesia (Strophopteria)'' Guo, 1985 *Genus '' Kedonella'' Polubotko, 1992 *Genus '' Kobayashites'' Hayami, 1959 *Genus '' Marmaronia'' Larghi, 200 *Genus ''

Panis This is a list of ancient Indo-Aryan peoples and tribes that are mentioned in the literature of Indic religions. From the second or first millennium BCE, ancient Indo-Aryan peoples and tribes turned into most of the population in the northern p ...

'' Stephenson, 1953 *Genus '' Permoperna'' (Nakazawa & Newell, 1968) *Genus '' Pseudoptera'' Meek, 1873 *Genus '' Tenuipteria'' Stephenson, 1955 *Genus '' Towapteria'' Nakazawa & Newell, 1968

References

{{Taxonbar, from=Q4849342 Prehistoric bivalve families Mississippian first appearances Bartonian extinctions