Symmoriida

Symmoriida is an extinct order of ratfish that contains three families. It was synonymized subjectively with Cladodontida by Lund; it was corrected as Symmoriiformes by Maisey. It was assigned to Cladoselachii by Goto et al.; to Elasmobranchii by Williams, and to Chondrichthyes by Sepkoski in 2002 and by Maisey in 2008. In the fossil record, they appear at the beginning of the Carboniferous. Most of them died out at the start of the Permian; however, a single tooth described by Guinot et al. from the Valanginian of France indicates that members of the family Falcatidae might have survived until the Early Cretaceous.