Megatrigoniidae

 Megatrigoniidae is an extinct family of fossil saltwater clams, marine bivalve molluscs in the subclass Palaeoheterodonta. This family of bivalves is known in the fossil record from the Jurassic period, Tithonian age, to the Cretaceous period, Maastrichtian age. Species in this family were facultatively mobile infaunal suspension feeders.
Subfamilies and genera.
Subfamilies and genera within the family Megatrigoniidae:
Distribution.
Fossils of this family have been found in Jurassic of Antarctica, Chile, India and in Cretaceous of Angola, Antarctica, Argentina, Austria, Chile, Colombia, Cuba, Ecuador, Egypt, France, Hungary, Italy, Japan, Libya, Madagascar, Mexico, Mozambique, New Zealand, Oman, Peru, Portugal, Serbia and Montenegro, South Africa, Spain, Trinidad and Tobago, Russia, Ukraine, United Arab Emirates, United Kingdom, United States and Yemen.