Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings.
They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth.
[2] In some animals (notably catfish), the presence or size of odontodes can be used in determining the sex.
[3] Odontodes typically cover the body of chondrichthyans (cartilaginous fishes), while mineralized dermal scales are characteristic of bony fishes.
Aquino et al. (2001) show scanning electron microscope images of odontodes on a catfish.