Bakevelliidae is an extinct family of prehistoric bivalves that lived from the Late Mississippian until the Middle Eocene.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 composition with a low amount of magnesium calcite. The family was named by William 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. 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 Stephenson, 1953 Genus Permoperna (Nakazawa & Newell, 1968) Genus Pseudoptera Meek, 1873 Genus Tenuipteria Stephenson, 1955 Genus Towapteria Nakazawa & Newell, 1968
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