Class Bivalvia Linnaeus, 1758

et: karbid; fi: simpukat; sv: musslor; ru: Двустворчатые;

Taxon ID: 55 / 2018-11-24
Belongs to: Mollusca
Sister taxa: Diplacophora | Gastropoda | Helcionelloida | Hyolitha | Paragastropoda | Rostroconchia | Tergomya | Cephalopoda
Contains: Isofilibranchia | Palaeoheterodonta | Protobranchia | Pteriomorphia
Stratigraphic range: Cambrian Quaternary | ~ 542,0–0,0 Ma
Baltoscandian species (in database): 44

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.

Visual identification guide (Bivalvia)


Selection of related publications

  • Křiž, 2008. A new bivalve community from the lower Ludlow of the Prague Basin (Perunica, Bohemia) [DOI]
  • Isakar & Sinitsyna, 1993. A new species Megalomoidea walliseri (Bivalvia) from the Silurian of Estonia
  • Isakar, 1991. Harjuan (Late Ordovician) new Bivalves and a new Gastropod from North Estonia
  • Isakar, 1990. Bivalvia and Gastropoda
  • Kisselev et al., 1990. Atlas of Upper Ordovician and Silurian molluscs from the nort-western part of East-European platform.
  • Liljedahl, 1989b. Fylgia baltica gen. et sp. nov. (Bivalvia, Mollusca) from the Silurian of Gotland [DOI]
  • Isakar & Sinitsyna, 1985. Redescription of E. Eichwald's Ordovician bivalve species
  • Isakar, 1985. New bivalve genus Kogulanychia from the Upper Silurian of Estonia
  • Sinicyna, 1983. New genus of Bivalve molluscs from the Middle Ordovician of north-east of East-European platform
  • Öpik, 1930a. Brachiopoda Protremata der estländischen ordovizischen Kukruse-Stufe
  • Öpik, 1930b. Beiträge zur Kenntnis der Kukruse-(C2-C3-)Stufe in Eesti. IV
  • Bekker, 1924b. The Devonian Rocks of the Irboska district (S. E. Estonia) with the description of a new cemented brachiopod
  • Bekker, 1921. The Kuckers Stage of the Ordovician Rocks in N-E Estonia