"Ledley also noted that there were no vertebrae or even cartilaginous elements in the so-called “caudal appendage."
I think a real, functioning "throwback" tail would required something more solid in it? Can't hang from trees or wag much with some soft, limp skin growth.
This occurs rarely, but the retaining of a caudal appendage (in this case, I'm not sure if it is one judging on the position).....
yes, it would be a "throwback" if vertebral structures WERE present.