Helicoprion prehistoric shark, illustration. This genus of shark existed from the late Carboniferous period (280 million years ago) until the early Triassic period (225 million years ago). This shark is known only from fossilised sets of teeth that form circular coils. It is thought that the tooth-whorl formed on the lower jaw and developed as newer teeth grew and pushed the older teeth further forward (shown in semi-transparent view at bottom). Shark skeletons are made of cartilage and do not fossilise well. The only parts that fossilise are teeth and parts of the fins. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Jensen, Mikkel Juul |
Bildgröße: | 6356 px × 5498 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |