Megamouth shark Baja California, Mexico, and samples taken from GenBank in order to perform a population genetic analyses of the megamouth shark; the results indicated no genetic diversity between populations found in different geographical locations, which indicates the species forms a single, highly migratory, interbreeding population. The first megamouth shark was captured on November 15, 1976, about 25 miles off the coast of Kāneohe, Hawaii, when it became entangled in the sea anchor of United States Navy ship "AFB-14". The species was identified as being of a new genus within the planktivorous shark species. Examination of the 4.5-m (14.7-ft), 750-kg (1,650-lb) specimen
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