>>1933Well, technically speaking, the cartillages in your ears ARE indeed support structures, so they do count as cartillagenous bones in that sense.
But they usually aren't referred to as such because it would stir confusion with our regular, human bones. Y'know… Bony bones, made of osein.
But sharks do have a cartilagenous skull, a spinal column with cartilagenous vertebrae, and cartilagenous ribs coming off from it, so you can't say that sharks don't have a skeleton, even if it's a cartilagenous one. But what is that skeleton made out of if not bones?