Are sturgeons a primitive fish?

Representatives of the sturgeon family have a very ancient history, and, as evidenced by archaeological finds, they lived on Earth about 80 million years ago, when dinosaurs were still the dominant species. These creatures have a simpler (one might even say, primitive) structure, like very ancient fossil fish. And they have changed little during evolution. So, for example, they have no scales, their spine is not bony, but cartilaginous, and there are no vertebrae in it at all. Despite this, they were able to perfectly adapt to all the changes.