The Gryphaeidae Family includes 10 species comprising only one subfamily (Pycnodonteinae)
and 4 genus (Hyotissa (6 species), Neopycnodonte (2), Pycnodonte (1), Empressostrea (1))

Phylum      : Mollusca
 Class       : ⤷Bivalvia 
  Subclass    : ⤷Autobranchia 
   Infraclass  : ⤷Pteriomorphia 
    Order       : ⤷Ostreida 
     Superfamily : ⤷Ostreoidea 
      Family      : ⤷Gryphaeidae

Common name : honeycomb oysters, foam oysters

Aspect : highly inequilateral and inequivalve; left valve (often attached) is larger, thicker, deeply concave/curved (like a bowl or hook); right valve (free) is smaller, flatter, acts as a lid; the outer surface of the shell is covered with flattened thorns and has 9 to 12 angular folds which give the opening a characteristic zigzag shape; pearly interior; hinge posterior to the umbo; size up to 30 cm

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

Environment : tropical to subtropical (Indo-Pacific, Caribbean); in shallow to deep water (0–500 m); on rocks, coral, other shells, artificial structures