Synechodontiformes

Synechodontiformes is an extinct order of prehistoric shark-like cartilaginous fish, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays.

Their placement in the group is uncertain, some authors have considered them to be members of the modern shark group Galeomorphi, while others have considered them to represent a stem-group to modern sharks, with some suggesting that they are basal to the last common ancestor of modern sharks and rays. There is also disagreement about the relationships between Triassic and earlier members of the group, only known from isolated teeth, and those from the Jurassic onwards, with the similarity between the two groups possibly being superficial.