Crocodile shark in a 1936 issue of "Zoological Magazine (Tokyo)" by ichthyologist Kiyomatsu Matsubara, based on a long specimen found at the Koti Fish Market in Japan. The type specimen is a long adult male found at a fish market in Su-ao, Taiwan. After being shuffled between the genera "Carcharias" and "Odontaspis" in the family Odontaspididae by various authors, in 1973 Leonard Compagno resurrected Jean Cadenat's 1963 subgenus "Pseudocarcharias" from synonymy for this species and placed it within its own family. The morphology of the crocodile shark suggests affinity with the megamouth shark (Megachasmidae), basking shark (Cetorhinidae), thresher sharks (Alopiidae), and mackerel
Pain in fish birds, frogs, salamander, reptiles, fish, and crustaceans. A recent article by Howard Browman and colleagues provides an overview of what different perspectives regarding fish pain and welfare mean to in the context of aquaculture, commercial fisheries, recreational fisheries, and research. It has been argued that fish can not feel pain because they do not have a sufficient density of appropriate nerve fibres. A typical human cutaneous nerve contains 83% GroupC nerve fibres, however, the same nerves in humans with congenital insensitivity to pain have only 24–28% C-type fibres. Based on this, James Rose, from the University of Wyoming, has argued