What is "gogoselachus"

Gogoselachus ("shark from the Gogo formation") is an extinct cartilaginous fish known from the late Devonian of Australia. It is one of the earliest well-preserved Devonian chondrichthyans (20 million years older than Cladoselache), as much more of the fish than just teeth and scales were preserved. This rare preservation reveals some unique discoveries about the evolution of the cartilage that was inside later cartilaginous fish such as sharks, rays, and chimaeras.