Megamouth shark by Leighton Taylor showed it to be an entirely unknown type of shark, making it – along with the coelacanth – one of the more sensational discoveries in 20th-century ichthyology. The pectoral fin of the megamouth shark was studied, along with the skeletal and muscular system of the megamouth shark to show its phylogenetic relationship to the other two sharks. , only 99 megamouth specimens had been caught or sighted. They have been found in the Pacific, Atlantic, and Indian Oceans. Japan, the Philippines and Taiwan have each yielded at least 10 specimens, the most of any single area, amounting
Fish intelligence is large and complex. In at least one important respect, it differs in internal structure from the mammalian cerebellum: The fish cerebellum does not contain discrete deep cerebellar nuclei. Instead, the primary targets of Purkinje cells are a distinct type of cell distributed across the cerebellar cortex, a type not seen in mammals. The circuits in the cerebellum are similar across all classes of vertebrates, including fish, reptiles, birds, and mammals. There is also an analogous brain structure in cephalopods with well-developed brains, such as octopuses. This has been taken as evidence that the cerebellum performs functions important to all