The arapaima or pirarucu, native to the Amazon. (Jeff Kubina via Wikipedia [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]) (CN) – The design of the ...

Teeth grew from the scales of primitive shark-like fish millions of years ago, research by scientists suggests. Old lineage cartilaginous fish like sharks, skates and rays that have skin which ...