New Scientist , 2nd July 2021
A pet fish adorned with tooth-like scales is helping biologists tackle a longstanding debate about the origin of teeth , and explore how body structures can be lost and regained during evolution.
The suckermouth armoured catfish is commonly found in pet shops and, unusually for a bony fish, has tooth-like structures called odontodes covering its skin. These physically resemble teeth, erupting from thickened patches of skin to form layered structures of pulp, dentine and enamel, and similar genes appear to be active in both during development. But which evolved first, and how did tissues gain or regain them?