Symmoriida

Symmoriida is an extinct order of holocephalians[1] that contains three families. It was synonymized subjectively with Cladodontida by Lund (1986); it was corrected as Symmoriiformes by Maisey (2008). It was assigned to Cladoselachii by Goto et al. (1988); to Elasmobranchii by Williams (1998), 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, but Dwykaselachus is known from the Artinskian-Kungurian of South Africa.[1] However, teeth described from the Valanginian of France[2] and Austria[3] indicates that members of the family Falcatidae might have survived until the Early Cretaceous.

Symmoriida Temporal range: 382.7–280 Ma PreꞒ Ꞓ O S D C P T J K Pg N Late Devonian - Early Permian (Members of the family Falcatidae might have survived until the Early Cretaceous in Europe.)
Symmorium
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Holocephali
Order:	†Symmoriida Zangerl, 1981
Families
†Symmoriidae †Falcatidae †Stethacanthidae