File:Evolution of cartilaginous fishes.png - Wikimedia Commons

File:Estonian Museum of Natural History - Psammolepis Alata.png

Diversity, Free Full-Text

Chondrichthyes

File:Pristis clavata (Dwarf sawfish) in Aqua park shinagawa.png

File:Caobs u0.png - Wikimedia Commons

File:Onchopristis numida.png - Wikipedia

Fish Skeletal System - Structure, Functions, and Composition

It's less than 2cm long, but this 400 million year old fossil fish

File:Edestus recon.png - Wikipedia

File:Calon u0.png - Wikimedia Commons

File:Hybodus hauffianus.png - Wikipedia