Elasmobranchii

Elasmobranchii (Elasmobranchii) is a class of organisms united by key anatomical and physiological traits. It contains 10 orders with 755 known species. Key order groups include Heterodontiformes, Hexanchiformes, Myliobatiformes, Orectolobiformes, Pristiophoriformes, and Rajiformes. Among its members, 239 species are currently classified as threatened (Critically Endangered, Endangered, or Vulnerable). It belongs to Chordates (Chordata).