I have been listening to your discussion. Arguing if his point of view is correct isn’t the issue. He has limited tools at the time and indicates that. The point is, was he a real person (seems he was), did he study these creatures (seems he did) therefore, are their real creatures. The discussion over how this creature arrived here and through which ancestral tree it arose is not the issue. He had no way of knowing and we still have no definitive answers.