The Cardiidae Family includes 297 species comprising 10 subfamilies (Fraginae (8 genus), Trachycardiinae (7), Cardiinae (7), Nemocardiinae (6), Lymnocardiinae (5), Orthocardiinae (4), ...)
and 54 genus (Vasticardium (40 species), Acrosterigma (31), Microcardium (17), Fulvia (17), Laevicardium (15), Fragum (12), ...)

Phylum      : Mollusca
 Class       : ⤷Bivalvia 
  Subclass    : ⤷Autobranchia 
   Infraclass  : ⤷Heteroconchia 
    Subterclass : ⤷Euheterodonta 
     Superorder  : ⤷Imparidentia 
      Order       : ⤷Cardiida 
       Superfamily : ⤷Cardioidea 
        Family      : ⤷Cardiidae

Common name : cockles

Aspect : equivalve (both valves equal) and equilateral (umbo centered); solid, sometimes thick; generally rounded and heart-shaped when viewed from the side; often inflated; radial ribs are very distinct and regular running from umbo to margin; ribs often bear spines, scales, or nodules; strong hinge with cardinal and lateral teeth; size varies from few centimeters (Cerastoderma) to 1,5m (giant clam, tridacna maxima)

Feeding : filtration of microorganisms in suspension (phytoplankton, zooplankton, detritus, and organic particles)

Environment : tropical to temperate coasts; abundant in Europe (Cerastoderma edule), North America (Clinocardium nuttallii), Indo-Pacific (Tridacna); from high tide line to ~100 m depth (most common <20 m); buried in sand, muddy sand, or gravel