Major groups of cartilaginous fishes
Example of an acanthodian Climatius reticulatus
Illustrator - Arthur Weasley. License - Creative Commons Attribution 3.0 Unported.
EXTINCT
Acanthodians are relatively small extinct fishes that have characteristics in between sharks and placoderms and reminiscent of later ray-finned fishes. Their skeletons are made of cartilage and their back fins have a spine on the side towards the head.
Chondrichthyes
These are the subset of fishes with jaws that have skeletons made of cartilage rather than bone, in contrast to the osteichyans (Arcopterygii and Sarcopterygii). There is so much variety that we can only give a few examples. Start with these and then see fishes in a new light as you explore online, in visits to aquariums and as you see fish up close and personal in diving, angling or at the grocery store.
Elasmobrach - Sharks
Photographer - Michael Aston,Elasmobranch - Rays
Photographer - J. Wiseman and S. Bernhardt, NOAA.
