Petalodus
Encyclopedia
Petalodus is an extinct genus of cartilaginous fish from the Permian
.
They were also in the Pennsylvanian.
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
.
They were also in the Pennsylvanian.