Bivalvia

Bivalvia Linnaeus, 1758

Bivalves

Taxon overview

Bivalvia is a class of marine and freshwater molluscs with laterally compressed bodies enclosed by a shell in two hinged parts. The majority are filter feeders and have no head or radula. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment on the seabed, where they are safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. A few bore into wood, clay or stone and live inside these substances. Some bivalves, such as the scallops, can swim.
The shell of a bivalve is composed of calcium carbonate, and consists of two, usually similar, parts called valves. These are joined together along one edge by a flexible ligament that, in conjunction with interlocking "teeth" on each of the valves, forms the hinge. This arrangement allows the shell to be opened and closed without the two halves becoming disarticulated. The shell is typically bilaterally symmetrical, with the hinge lying in the sagittal plane. Adult shell sizes vary from fractions of a millimetre to over a metre in length, but the majority of species do not exceed 10 cm.
Bivalves appear in the fossil record first in the early Cambrian more than 500 million years ago.

Selection of related publications
Toom, U., Vinn, O., Isakar, M., Madison, A., Hints, O. 2020. Small faecal pellets in Ordovician shelly fossils from Estonia, Baltoscandia. Estonian Journal of Earth Sciences 69, 1, 1-19. DOI:10.3176/earth.2020.01
Křiž, J. 2008. A new bivalve community from the lower Ludlow of the Prague Basin (Perunica, Bohemia). Bulletin of Geosciences 83, 3, 237-280. DOI:10.3140/bull.geosci.2008.03.237
Hinz-Schallreuter, I. 1995. Middle Cambrian Bivalvia from Bornholm and a review of Cambrian bivalved Mollusca. Geschiebekunde aktuell 11, 3, 71-85.
Liljedahl, L. 1992. Yonginella, a new bivalve (Mollusca) from the Silurian of Gotland. Journal of Paleontology 66, 2, 211-214. DOI:10.1017/S0022336000033734
Isakar, M. 1991. Harjuan (Late Ordovician) new Bivalves and a new Gastropod from North Estonia. Acta et Commentationes Universitatis Tartuensis 934, , 43-60. Eesti Ordoviitsiumi paleontoloogia ja stratigraafia, pp. 43-60.
Isakar, M. 1990. Bivalvia and Gastropoda. Field Meeting Estonia 1990. An Excursion Guidebook, pp. 64-65.
Kiselev, G. N., Sinitsyna, I. N., Isakar, M. A., Mironova, M. G., Saladzhius, V. Y. 1990. Atlas of Upper Ordovician and Silurian molluscs from the nort-western part of East-European platform.
Liljedahl, L. 1989. Fylgia baltica gen. et sp. nov. (Bivalvia, Mollusca) from the Silurian of Gotland. GFF 111, 4, 339-345. DOI:10.1080/11035898909453132
Isakar, M., Sinitsyna, I. 1985. Redescription of E. Eichwald's Ordovician bivalve species. Proceedings of the Academy of Sciences of the Estonian SSR. Geology 34, 2, 46-54.
Isakar, M. 1985. New bivalve genus Kogulanychia from the Upper Silurian of Estonia. Proceedings of the Academy of Sciences of the Estonian SSR. Geology 34, 1, 30-31.
Sinicyna, I. N. 1983. New genus of Bivalve molluscs from the Middle Ordovician of north-east of East-European platform. Paleontologicheski Zhurnal , 29-32. DOI:Paleontologičeskij sbornik
Soot-Ryen, H. 1969. A new species of Babinka (Bivalvia) from the Lower Ordovician of Öland, Sweden. Palaeontology 12, 2, 173-177.
Saladžius, V. J. 1966. Mollusk fauna of the Silurian deposits of the south of the East Baltic territory. Palaeontology and stratigraphy of the Baltic and the Byelorussia. Number I (VI), pp. 31-73.
Soot-Ryen, H. 1964. Nuculoid ppelecypods from the Silurian of Gotland. Arkiv för Mineralogi och Geologi 3, 28, 489-519.
Öpik, A. 1930. Beiträge zur Kenntnis der Kukruse-(C2-C3-)Stufe in Eesti. IV. Tartu Ülikooli Geoloogia Instituudi Toimetused 24, 1-34.
Öpik, A. 1930. Brachiopoda Protremata der estländischen ordovizischen Kukruse-Stufe. Tartu Ülikooli Geoloogia Instituudi Toimetused 20, 1-261.
Bekker, H. 1924. Devon Irboska ümbruses: stratigraafia, fauna ja paleogeograafia. Eesti Loodusteaduse Arhiiv X, 1, 1-55.
Bekker, H. 1921. The Kuckers stage of the Ordovician Rocks in NE Estonia. Acta et Commentationes Universitatis Tartuensis II, 1, 1-90.