Claim: Plesiotrygon belongs to the family of Muraenidae, and under the order of Anguilliformes from kingdom Animalia.
Evidence: Plesiotrygon, the antenna rays, is a small genus of freshwater stingrays in the family Potamotrygonidae endemic to the Amazon basin in South America. Family: Potamotrygonidae Order: Myliobatiformes Kingdom: Animalia 
River stingrays or freshwater stingrays are Neotropical freshwater fishes of the family Potamotrygonidae in the order Myliobatiformes, one of the four orders of batoids, cartilaginous fishes related to sharks. Myliobatiformes /mɪliˈɒbətɪfɔːrmiːz/ is one of the four orders of batoids, cartilaginous fishes related to sharks. Kingdom: Animalia Order: Myliobatiformes
Compagno, 1973 
Moray eels, or Muraenidae (/ˈmɒreɪ, məˈreɪ/), are a family of eels whose members are found worldwide. Family: Muraenidae
Rafinesque, 1810 Order: Anguilliformes