Nuculanida

order of bivalves Nuculanida (Nuculanida) is an order comprising closely related families of organisms. It contains 2 families with 4 known species. This includes the family groups Nuculanidae, and Yoldiidae. Among its members, 2 species are currently classified as threatened (Critically Endangered, Endangered, or Vulnerable). It belongs to Bivalvia (Bivalvia).