Large parts consisted of cartilage that did not fossilize.
No full fossil is known, mainly because parts of the skeleton were made of cartilage, which does not fossilise.
No full fossil is known, mainly because parts of the skeleton were made of cartilage, which does not fossilise.
이 텍스트를 단순화: Large parts consisted of cartilage that did not fossilize. 산출: